Field of study: Human genetics and social
issues Significance: Aggression refers to behavior directed toward causing harm to others. Aggressive antisocial behavior is highly heritable, and antisocial behavior (ASB) during childhood is a good predictor of ASB in adulthood and crime. Physical acts of aggression are sometimes distinguished from the more context-sensitive “covert” ASBs, including theft, truancy, and negative peer interactions.
Key terms
antisocial behavior (ASB): behavior that violates rulesorconventions ofsociety and/or personal rights
impulsivity: a tendency to act quickly without planning or a clear goal in mind
irritability: atendency to overreact tominor stimuli; short-temperedness or volatility
liability: the riskofexhibitinga behavior; the higher one’s score for a measure of liability, the greater is one’s the risk of exhibiting the behavior
serotonin: aneurotransmitter, 5-hydroxytryp-tamine (5-HT), present in blood platelets, the gastrointestinal tract, and certain regions of the brain, which plays role in initiating sleep, blood clotting, and stimulating the heartbeat, and levels of which have been correlated with aggressive behavioraswell as depression and panic disorder
Aggression and Related Behaviors
Aggression or agonistic behavior in animals is usually an adaptive response to specific environmental situations during competition for resources, as in establishing dominance and a territory or in sexual competition. Rat and mice studies indicate it is partly genetic, because selective breeding produces strains that differ in levels of aggression. Human aggression can also represent a variety of natural responses to challenging situations. Measures of aggression vary, but of greatest concern are antisocial behaviors (ASBs) such as crime and delinquency and whether some individuals are more likely to engage in these behaviors than others.
The earliest evidence for a genetic contribution to these complex behaviors comes from twin and adoptee studies. Genes also increase the liability for many clinical conditions that include aggressive behaviors, suchasconduct disorder (physically aggressive acts such as bullying or forced sexual activity) and antisocial personality disorder (persistent violation of social norms, including criminal behavior) and for personality traits that often accompany aggression, such as impulsivity and irritability. Differences in measuring ASBs partly account for the variability in heritability estimates, which range from 7 to 81 percent, but many studies indicate a heritability for genetic influences of 0.40-0.50, a minor influence of shared environment, and a much more significant influence of nonshared environment (environment unique to the individual).
Aggression and Human Development
Aggressive behavior develops in children through a complex interaction of many environmental and biological factors. Also increasing liability for aggression and perhaps criminality are such factors as low socioeconomic status and parental psychopathology. A consistent finding is that the measure of the activity of the central nervous system’s serotonin correlates inversely with levels of lifetime aggression, tendency to physically assault, irritability, and impulsivity. Some of the implicated genes regulate serotonin synthesis, release, and reuptake as well as metabolism and receptor activation, and vary from individual to individual. Seroto-nergic dysfunction is also noted in alcoholism with aggression and in suicide attempters and completers. Brain injuries can also exacerbate tendencies to exhibit ASBs.
Some aggression, however, is a normal part of development. Thus, Terrie Moffitt and colleagues distinguish between “adolescent-limited aggression”—times when most adolescents are rebelling against adult authority—and “life-course persistent” ASB, which likely reflects neuropsychological deficits and specific temperaments that are often exacerbated in un-supportive family settings. Genetic factors play a smaller role in adolescent delinquency and are consistent with aggression at this age as a developmental response to social context.
Sex Differences
A significant feature of ASB is a marked difference between the sexes. Males exhibit higher levels of physical aggression and violence at every age in all situations except in the context of partner violence (where females exceed males). More males than females are diagnosed with conduct disorderateveryage. More males than females begin actsoftheft and violenceat every age. Males also exhibit higher rates of risk factors, suchas impaired neurocognitive status, increased hyperactivity, and difficulties with peers. Females are rarely identified with the life-course persistent form of ASB; the male:female sex ratio is 10:1. Antisocial male and female adolescents tend to associate and often marry and reproduce at younger ages. The role that hormones, particularly testosterone, may play in these differences is not clear.
Social Significance
There is much controversy surrounding the efforts to identify genes associated with aggression or crime, especially now that genome sequencing is easier than ever. Many demand that the privacy of individuals be protected because the presence of specific genes does not dictate behavioral outcomes: Genes do not determine socially defined behaviors but only act on physiological systems.Inaddition, what constitutes acceptable or unacceptable behavior for individuals is culturally defined. Biological and environmental risk factors may increase an individual’s liability to commit an act of aggression or crime, but the behavior must be interpreted within its specific context. Criminal law presumes that behavior is a function of free will, and most attempts to use genes as a mitigating factor in the courtroom have been unsuccessful. Efforts to prevent crime and violence must include consideration of all factors. Family milieu and parental competence are just as important as impaired cognitive mechanisms suchasreduced serotonin activity.Anim-balance in brain chemistry leading to impul-sivity or aggression may be ameliorated by a
supportive home setting, by medication, or by adequate nutrition.
—Joan C. Stevenson See also: Aging; Behavior; Biological Determinism; Criminality; DNA Fingerprinting; Forensic Genetics; Sociobiology; Steroid Hormones; XYY Syndrome.
Further Reading
Bock, Gregory R., and Jamie A. Goode. Genetics of Criminal and Antisocial Behaviour. New York: John Wiley & Sons, 1996. This symposium was held at the Ciba Foundation in London in 1995 and includes a representative sample of the research foci in this arena, followed by discussions.
Fishbein, Diana H., ed. The Science, Treatment, and Prevention of Antisocial Behaviors: Application to the Criminal Justice System. Kingston, N.J.: Civic Research Institute, 2000. An excellent set of reviews on aggression and the many associated behaviors and mental disorders.
Lesch, Klaus Peter, and Ursula Merschdorf. “Impulsivity, Aggression, and Serotonin: A Molecular Psychobiological Perspective.” Behavioral Sciences and the Law 18, no. 5 (2000): 581-604. A wonderful review of all the interacting factors, including all the elements of the serotonin system.
Moffitt, Terrie E., Avshalom Caspi, Michael Rutter, and Phil A. Silva. Sex Differences in Antisocial Behaviour: Conduct Disorder, Delinquency, and Violence in the Dunedin Longitudinal Study. New York: Cambridge University Press, 2001. Sex differences are documented as children grow up.
Roush, Wade. “Conflict Marks Crime Conference.” Science 269, no. 5232 (1995): 1808-1809. An excellent description of the pros and cons of genetic research on ASB.
Sunday, May 10, 2009
Friday, February 6, 2009
Creationism Versus Evolution
The immiscible patterns of thought that concern us in this book arc those of creationists and evolutionists. Christian fundamentalists accept without question that divine creation is the explanation for the diversity of life wc sec today—the many different species of plants, animals, fungi, and microorganisms that flourish around the globe. Their position is based on their reading of Genesis, with its familiar story of the creation week—six days during which God created all of nature. On the first day God created heaven and earth and light and darkness; on the second He made the firmament and divided the waters; on the third day He separated land from the seas and created the land plants; on the fourth day He created the sun, moon, and other celestial bodies; on the fifth day animals in the sea and birds in the air came into being; on the sixth day the land animals appeared, and God also created, in his own image, two human beings. Until recently the accepted date for creation, based on a tally of the generations ("begats") listed in the King (ames version of the Bible, was 4004 B.C. Creationists assume that all creatures living today arc the same as when they were created. That is, there has been no evolution.
The scientific version of these events is quite different. Tentative estimates place the origin of the universe in the neighborhood of 15 billion years ago. The sun—a second-generation star—and its orbiting planets formed about 4.5 billion years ago from the interstellar debris created by the explosion of massive first-generation stars. The Earth started out in a molten state but cooled enough to form a solid crust by about 3.8 billion years ago. The first evidence of life dates to about 3.5 billion years ago and consists of very simple cells without a nucleus (prokaryotcs), much like bacteria living today. The oldest known cells with nuclei (cukaryotcs) date to about 2.7 billion years ago. The earliest multicclled organisms discovered so far date to about 1.7 billion years ago. Fossils of the first members of the animal kingdom date to about 650 million years ago. At the beginning of the Cambrian period, about 570 million years ago, animal life became abundant and highly diversified; the fossil record from this period is much better known than that of earlier times. From that point until today, there has been an incredible evolution of life (both plants and animals), with different species appearing, flourishing, and then becoming extinct or evolving into still other species.
The evolutionists' and the creationists' accounts for the origins and diversity of life could hardly be more incompatible. Strict creationists base their account on faith—a belief that Genesis was divinely inspired and provides the only true explanation for the origins of the universe, living creatures, and the many variations in organisms that wc observe today and find in the fossil record.
beliefs, do not understand why any person familiar with the data would reject an explanation based on confirmablc knowledge and accept instead a supernatural concept based on faith alone. Similarly, deeply committed fundamentalists wonder why anyone would reject the Word of God in favor of what a bunch of scientists has to say.
The long strands of human history have seen many conflicts between science and religion, and sadlv, thev have often turned violent and bloody. It is fascinating to consider how individuals come to hold such conflicting explanations for the same phenomena and whv thev hold them so tenaciously. Wc know that parents and society arc remarkably efficient in transmitting patterns of thought and behavior to successive generations. This cultural inheritance sets up rules for behavior that help individuals get along within their group. It also provides each generation with an avenue for learning new things, and it creates order within the society. But beyond these practical advantages, a culture's unique belief systems may retain their enormous power from generation to generation in large part because they supply impressionable young people with answers to many questions they quite naturally ask, such as "Where did I come from?" "Who made me?" "Who will take care of me?" "Why do people die?" "What happens to me after I die:"
Such inquisitiveness seems to be part of our human inheritance. For hundreds of thousands of years, carlv human populations were illiterate and encapsulated in small tribes whose very survival was regularly endangered. Human beings lived a marginal existence like all other animals, dependent on the ability of the environment to sustain them and on their skills and knowledge of how to obtain food, water, and shelter. But within every society, some individuals must have cx-hibitcd a much stronger desire than their peers not just to survive from moment to moment but to understand themselves and the world around them. They asked questions and sought answers. According to anthropologists who have studied hunter-gatherer cultures, the explanations inquisitive tribe members come up with usually include both natural and supernatural elements. Natural things and processes arc those that can be observed: wind, rain, birth, death, animals, plants, fire, night, day, and the seasons. But for each of these observable entities, a supernatural clement of some kind usually figures in the explanation as well. For example, although death is now accepted by most people in Western societies as due to natural causes such as disease, accidents, or the ravages of age, people in some parts of the world still believe that death results from the displeasure of a god or spirit or the effects of a curse such as the evil eve.
The tenacity with which people hold onto beliefs in the supernatural or paranormal has been the subject of much scientific investigation. The results arc complex and unexpected. Two psychologists, Barry Singer and Victor A. Bcnassi (1981, 49—51), made an extensive study of occult beliefs in the United States and offer this summary:
Far from being a "fad," preoccupation with the occult now forms a pervasive part of our culture. Garden-variety occultisms such as astrology and ESI* [extrasensory perception] have swelled to historically unprecedented levels.... Belief in ESI* for instance, is consistently found to be moderate or strong in 80—90% of our population;... in one survey it ranked as our most popular supernatural belief, edging out belief in God in strength and prevalence.
Experiments which have attempted to encourage discontinuation of occult or illusory beliefs by motivating subjects to think through their judgments more carefully ... have uniformly revealed an astonishing resistance to change of such beliefs.... [Such] stubbornness of illusory and occult beliefs is typical rather than exceptional.
By way of explaining the origin of beliefs in the paranormal, Singer and Bcnassi point out that if human beings do not understand the reason for a given event, thev tend to invent one, and the kind of reason they invent will depend on the intellectual baggage they carry with them. A simple, rational, natural explanation might be preferred, but if that cannot be developed, the need to explain remains and supernatural causes may be invoked. Thus, according to these investigators, one factor in the great increase of interest in the occult in the Lnitcd States is inadequate science education in the schools. Over half of the students they tested did not know, for example, that the level of water in a partially filled glass remains parallel to the Earth's surface as the glass is tipped.
Singer and Bcnassi suggest that the "iffincss" of science is a second factor that weighs against the acceptance of scientific explanations over supernatural ones. Scientists tend to resist claiming that their statements arc true by any absolute measure, stating only that they represent the best available explanation based on existing data. As Thomson (1997,219) expresses it, the facts of science arc "temporary way-stations on the long path to the refinement of knowledge." For many people, this tentativeness is a pale substitute for the finality and certainty of supernatural explanations.
A third factor that has increased interest in the occult is the media, which report stories about UFOs (unidentified flying objects), psvehic healing, people who claim that the dead speak through them, and ghosts. Splendid examples of articles of this kind can usually be found in publications stacked at the checkout counters of supermarkets. The media rarely provide scientific analyses of these reports. Added to this "news from the other side" arc highly entertaining motion pictures and television dramas that contain supernatural and superhuman feats. And of course even our own dreams can be quite extraordinary and entertaining, carrying us into compelling worlds where the constraints of waking reality no longer apply.
But Singer and Bcnassi found that the biggest factor bv far in people's acceptance of the occult is organized religion. Most people profess a belief in some religion, and essentially all religions accept miracles as a given. This institutionalized belief in miracles, according to Singer and Bcnassi, has a spillover effect into other realms of life and accounts in large part for people's acceptance of paranormal events ranging from visits bv angels to alien abductions.
Just how rigid occult beliefs can be is documented in an interesting experiment done with students in a psychology course at Concordia Lnivcrsity in Montreal (Gray 1984). The course was called "The Science and Pscudoscicncc of Paranormal Phenomena." Students were given a test at the beginning of the class to sec whether they believed in ESP, ghosts, or miracles (sec table 1). At the end of the semester they were asked the same questions to sec what effect studying these phenomena would have on their beliefs. Then, to get an estimate of the stability of anv change in beliefs, the students were asked the same questions a year later. Occult beliefs declined by the end of the course but usually bv trivial percentages. After one year, belief in the paranormal had moved back to levels close to those before the course was taken. In some cases it was slightly higher. This one-semester course designed to reduce students' belief in the paranormal was not a success. Lawson and Wcscr (1990, 589) report similar findings in another study and note that "the less skilled rcasoncrs were more likely to initially hold the nonscicntific beliefs and were less likely to change those beliefs during instruction. It was also discovered that less skilled rcasoncrs were less likclv to be strongly committed to the scientific beliefs."
Should we conclude that a willingness to accept supernatural explanations over scientific ones has been hardwired into the human brain—that it is "human nature" to seek meaning bevond the confines of the natural world: Perhaps, but an alternative—and to my mind more probable—hypothesis is that one's patterns of thought and belief arc the result of influences very early in life associated with family, church, friends, community, books, other media, and the schools. Children almost always develop the habits and beliefs of the family and culture to which they belong; indeed, the fidelity of cultural inheritance often seems as strong as the fidelity of genetic inheritance. Most children in the Lnitcd States grow up in communities where thev see.
The scientific version of these events is quite different. Tentative estimates place the origin of the universe in the neighborhood of 15 billion years ago. The sun—a second-generation star—and its orbiting planets formed about 4.5 billion years ago from the interstellar debris created by the explosion of massive first-generation stars. The Earth started out in a molten state but cooled enough to form a solid crust by about 3.8 billion years ago. The first evidence of life dates to about 3.5 billion years ago and consists of very simple cells without a nucleus (prokaryotcs), much like bacteria living today. The oldest known cells with nuclei (cukaryotcs) date to about 2.7 billion years ago. The earliest multicclled organisms discovered so far date to about 1.7 billion years ago. Fossils of the first members of the animal kingdom date to about 650 million years ago. At the beginning of the Cambrian period, about 570 million years ago, animal life became abundant and highly diversified; the fossil record from this period is much better known than that of earlier times. From that point until today, there has been an incredible evolution of life (both plants and animals), with different species appearing, flourishing, and then becoming extinct or evolving into still other species.
The evolutionists' and the creationists' accounts for the origins and diversity of life could hardly be more incompatible. Strict creationists base their account on faith—a belief that Genesis was divinely inspired and provides the only true explanation for the origins of the universe, living creatures, and the many variations in organisms that wc observe today and find in the fossil record.
beliefs, do not understand why any person familiar with the data would reject an explanation based on confirmablc knowledge and accept instead a supernatural concept based on faith alone. Similarly, deeply committed fundamentalists wonder why anyone would reject the Word of God in favor of what a bunch of scientists has to say.
The long strands of human history have seen many conflicts between science and religion, and sadlv, thev have often turned violent and bloody. It is fascinating to consider how individuals come to hold such conflicting explanations for the same phenomena and whv thev hold them so tenaciously. Wc know that parents and society arc remarkably efficient in transmitting patterns of thought and behavior to successive generations. This cultural inheritance sets up rules for behavior that help individuals get along within their group. It also provides each generation with an avenue for learning new things, and it creates order within the society. But beyond these practical advantages, a culture's unique belief systems may retain their enormous power from generation to generation in large part because they supply impressionable young people with answers to many questions they quite naturally ask, such as "Where did I come from?" "Who made me?" "Who will take care of me?" "Why do people die?" "What happens to me after I die:"
Such inquisitiveness seems to be part of our human inheritance. For hundreds of thousands of years, carlv human populations were illiterate and encapsulated in small tribes whose very survival was regularly endangered. Human beings lived a marginal existence like all other animals, dependent on the ability of the environment to sustain them and on their skills and knowledge of how to obtain food, water, and shelter. But within every society, some individuals must have cx-hibitcd a much stronger desire than their peers not just to survive from moment to moment but to understand themselves and the world around them. They asked questions and sought answers. According to anthropologists who have studied hunter-gatherer cultures, the explanations inquisitive tribe members come up with usually include both natural and supernatural elements. Natural things and processes arc those that can be observed: wind, rain, birth, death, animals, plants, fire, night, day, and the seasons. But for each of these observable entities, a supernatural clement of some kind usually figures in the explanation as well. For example, although death is now accepted by most people in Western societies as due to natural causes such as disease, accidents, or the ravages of age, people in some parts of the world still believe that death results from the displeasure of a god or spirit or the effects of a curse such as the evil eve.
The tenacity with which people hold onto beliefs in the supernatural or paranormal has been the subject of much scientific investigation. The results arc complex and unexpected. Two psychologists, Barry Singer and Victor A. Bcnassi (1981, 49—51), made an extensive study of occult beliefs in the United States and offer this summary:
Far from being a "fad," preoccupation with the occult now forms a pervasive part of our culture. Garden-variety occultisms such as astrology and ESI* [extrasensory perception] have swelled to historically unprecedented levels.... Belief in ESI* for instance, is consistently found to be moderate or strong in 80—90% of our population;... in one survey it ranked as our most popular supernatural belief, edging out belief in God in strength and prevalence.
Experiments which have attempted to encourage discontinuation of occult or illusory beliefs by motivating subjects to think through their judgments more carefully ... have uniformly revealed an astonishing resistance to change of such beliefs.... [Such] stubbornness of illusory and occult beliefs is typical rather than exceptional.
By way of explaining the origin of beliefs in the paranormal, Singer and Bcnassi point out that if human beings do not understand the reason for a given event, thev tend to invent one, and the kind of reason they invent will depend on the intellectual baggage they carry with them. A simple, rational, natural explanation might be preferred, but if that cannot be developed, the need to explain remains and supernatural causes may be invoked. Thus, according to these investigators, one factor in the great increase of interest in the occult in the Lnitcd States is inadequate science education in the schools. Over half of the students they tested did not know, for example, that the level of water in a partially filled glass remains parallel to the Earth's surface as the glass is tipped.
Singer and Bcnassi suggest that the "iffincss" of science is a second factor that weighs against the acceptance of scientific explanations over supernatural ones. Scientists tend to resist claiming that their statements arc true by any absolute measure, stating only that they represent the best available explanation based on existing data. As Thomson (1997,219) expresses it, the facts of science arc "temporary way-stations on the long path to the refinement of knowledge." For many people, this tentativeness is a pale substitute for the finality and certainty of supernatural explanations.
A third factor that has increased interest in the occult is the media, which report stories about UFOs (unidentified flying objects), psvehic healing, people who claim that the dead speak through them, and ghosts. Splendid examples of articles of this kind can usually be found in publications stacked at the checkout counters of supermarkets. The media rarely provide scientific analyses of these reports. Added to this "news from the other side" arc highly entertaining motion pictures and television dramas that contain supernatural and superhuman feats. And of course even our own dreams can be quite extraordinary and entertaining, carrying us into compelling worlds where the constraints of waking reality no longer apply.
But Singer and Bcnassi found that the biggest factor bv far in people's acceptance of the occult is organized religion. Most people profess a belief in some religion, and essentially all religions accept miracles as a given. This institutionalized belief in miracles, according to Singer and Bcnassi, has a spillover effect into other realms of life and accounts in large part for people's acceptance of paranormal events ranging from visits bv angels to alien abductions.
Just how rigid occult beliefs can be is documented in an interesting experiment done with students in a psychology course at Concordia Lnivcrsity in Montreal (Gray 1984). The course was called "The Science and Pscudoscicncc of Paranormal Phenomena." Students were given a test at the beginning of the class to sec whether they believed in ESP, ghosts, or miracles (sec table 1). At the end of the semester they were asked the same questions to sec what effect studying these phenomena would have on their beliefs. Then, to get an estimate of the stability of anv change in beliefs, the students were asked the same questions a year later. Occult beliefs declined by the end of the course but usually bv trivial percentages. After one year, belief in the paranormal had moved back to levels close to those before the course was taken. In some cases it was slightly higher. This one-semester course designed to reduce students' belief in the paranormal was not a success. Lawson and Wcscr (1990, 589) report similar findings in another study and note that "the less skilled rcasoncrs were more likely to initially hold the nonscicntific beliefs and were less likely to change those beliefs during instruction. It was also discovered that less skilled rcasoncrs were less likclv to be strongly committed to the scientific beliefs."
Should we conclude that a willingness to accept supernatural explanations over scientific ones has been hardwired into the human brain—that it is "human nature" to seek meaning bevond the confines of the natural world: Perhaps, but an alternative—and to my mind more probable—hypothesis is that one's patterns of thought and belief arc the result of influences very early in life associated with family, church, friends, community, books, other media, and the schools. Children almost always develop the habits and beliefs of the family and culture to which they belong; indeed, the fidelity of cultural inheritance often seems as strong as the fidelity of genetic inheritance. Most children in the Lnitcd States grow up in communities where thev see.
When Worlds Collide
Human remains so encountered arc always of concern—"Who was it?" and "Who did it?"—so the students called the police. In an effort to answer those two questions the police turned the bones over to the local coroner. Burial grounds of Native Americans arc sometimes encountered in that part of the Northwest, and the Native American Graves Protection and Reparation Act, passed in 1990, required that any such remains be returned for burial to the tribe to which they belonged. The bones appeared to be of great age, and so it was assumed that the skeleton must be one of a Native American, since settlers of European origin reached the West Coast only a few centuries ago. But closer study suggested otherwise.
To solve the puzzle, the bones were examined by an anthropologist, [ames Chatters, a specialist in skeletal remains of human beings. Such professionals can determine sex, size, age, cause of death, and racial type with considerable accuracy. Examination showed the skeleton to be that of a 50-ycar-old male of medium build, his teeth well worn and a stone arrowhead imbedded in his hip bone. Radiometric methods determined that the man died about nine thousand years ago long before human beings of European origin first arrived in the New World, according to conventional historical accounts. Yet the skeleton had Caucasoid features. Chatters took the bones to another anthropologist for an opinion, without giving a hint of his analysis, and was told that the skeleton was of a Caucasian male. Even when Chatters revealed the age of the bones, the second anthropologist stuck to her original identification. A third anthropologist familiar with the skeletal features of modern tribes of Native Americans concluded that the skeleton could not be assigned to any one of them.
Finding the nearly ninc-thousand-ycar-old skeleton of a Caucasoid male in any part of the New World is puzzling in the extreme. Traditionally, anthropologists have thought that the first human beings to inhabit the Western Hemisphere crossed from Siberia to Alaska about 15,000 years ago. Some now believe that the event occurred much earlier, but in any case these immigrants from Siberia were of the Mongolian racial type, as arc Native Americans—not Caucasoids. Anthropologists know that a few nameless fishermen from Western Europe came to the eastern shores of the New World before Columbus's arrival in 1492, as did the Vikings, but Caucasians did not come in large numbers until early in the sixteenth century.
So who was the Caucasoid Kcnncwick Man who arrived thousands of years before the Vikings, Columbus, Cortcz, and Pizarro? Needless to say, this is a most exciting and important question, not only for anthropologists and historians but for many nonprofessionals as well. There have even been some speculations that Caucasoid people may have been the original inhabitants of the New World. Thus, for scientists and others interested in such historical questions, further studies on Kcnncwick Man arc overwhelmingly important.
For a while it looked as though these investigations would never take place. In an effort to comply with the federal Native American Graves Protection and Reparation Act, the Army Corps of Engineers assumed control of the bones, placed them in a vault, and refused to allow any further examination of them by scientists. The Umatilla tribe, who live near the site of discovery, asked to have the bones returned to them, in which case the skeleton would be secretly buried and never be available for study. A group of anthropologists went to court to stop the Corps from complying with the tribe's request. The anthropologists claimed that the Umatillas were not in that part of the Northwest when Kcnncwick Man lived; hence, he could not be one of their ancestors. And of course his Caucasoid skeletal features led to the same conclusion. Thus, the available scientific evidence is that Kcnncwick Man was not a Umatillan or any other Native American.
In response to that hypothesis, a leader of the tribe, Armand Min-thorn, stated this position:
Our ciders have taught us that once a body goes into the ground, it is meant to stay there until the end of time.... If this individual is truly over 9,000 years old, that only substantiates our belief that he is Native American. From our oral histories, we know that our people have been part of this land since the beginning of time. We do not believe that our people migrated here from another continent, as the scientists do. ... Scientists believe that because the individual's head measurements do not match ours, he is not Native American. Our elders have told us that Indian people did not always look the way we look today. Some scientists say that if this individual is not studied further, we, as Indians, will be destroying evidence of our history. We already know our history. It is passed on to us through our elders and through our religious practices.
As of early 2001, the matter remains unsettled. Nevertheless the two perspectives—the anthropologists' and the Native Americans'— provide a classic example of two polar points of view that I will analyze throughout this book. One point of view rests on the questions and methods of science. The other rests on cultural beliefs that have been passed down from generation to generation. One side seeks a solution to a problem of intense interest to scientists and historians; the other side docs not recognize that there is a problem that needs a solution.
This dispute over the future of Kcnncwick Man represents a clash between two immiscible patterns of thought. Another example (reported in the New Yor^ Times on August 29, 1997) comes from Afghanistan, where the Taliban, a Muslim sect, have gained control of much of the nation and arc enforcing conformity to the Sharia, sacred Islamic law. According to this code, thieves must be punished by having their hands and feet cut off; couples caught in adulterous acts must be stoned to death; and if women do not cover themselves from head to foot, the young Taliban enforcers deal them a severe flogging. The young zealots have even beaten women for wearing white socks or plastic sandals.
The head of the General Department for the Preservation of Virtue and Prevention of Vice, Alhaj Maulavi Qalamuddin, explains the Taliban point of view: "Some women want to show their feet and ankles. They arc immoral women. They want to give a hint to the opposite sex." This must be controlled to "prevent impure thoughts in men"; "if we consider sex to be as dangerous as a loaded Kalashnikov rifle, it is because it is the source of all immorality." The rules of the Sharia relating to women arc harsh in other respects, by late-twenticth-ccntury standards in the West. Women arc prohibited from working or obtaining an education or even receiving medical treatment, and after puberty they arc almost entirely secluded in their homes.
To solve the puzzle, the bones were examined by an anthropologist, [ames Chatters, a specialist in skeletal remains of human beings. Such professionals can determine sex, size, age, cause of death, and racial type with considerable accuracy. Examination showed the skeleton to be that of a 50-ycar-old male of medium build, his teeth well worn and a stone arrowhead imbedded in his hip bone. Radiometric methods determined that the man died about nine thousand years ago long before human beings of European origin first arrived in the New World, according to conventional historical accounts. Yet the skeleton had Caucasoid features. Chatters took the bones to another anthropologist for an opinion, without giving a hint of his analysis, and was told that the skeleton was of a Caucasian male. Even when Chatters revealed the age of the bones, the second anthropologist stuck to her original identification. A third anthropologist familiar with the skeletal features of modern tribes of Native Americans concluded that the skeleton could not be assigned to any one of them.
Finding the nearly ninc-thousand-ycar-old skeleton of a Caucasoid male in any part of the New World is puzzling in the extreme. Traditionally, anthropologists have thought that the first human beings to inhabit the Western Hemisphere crossed from Siberia to Alaska about 15,000 years ago. Some now believe that the event occurred much earlier, but in any case these immigrants from Siberia were of the Mongolian racial type, as arc Native Americans—not Caucasoids. Anthropologists know that a few nameless fishermen from Western Europe came to the eastern shores of the New World before Columbus's arrival in 1492, as did the Vikings, but Caucasians did not come in large numbers until early in the sixteenth century.
So who was the Caucasoid Kcnncwick Man who arrived thousands of years before the Vikings, Columbus, Cortcz, and Pizarro? Needless to say, this is a most exciting and important question, not only for anthropologists and historians but for many nonprofessionals as well. There have even been some speculations that Caucasoid people may have been the original inhabitants of the New World. Thus, for scientists and others interested in such historical questions, further studies on Kcnncwick Man arc overwhelmingly important.
For a while it looked as though these investigations would never take place. In an effort to comply with the federal Native American Graves Protection and Reparation Act, the Army Corps of Engineers assumed control of the bones, placed them in a vault, and refused to allow any further examination of them by scientists. The Umatilla tribe, who live near the site of discovery, asked to have the bones returned to them, in which case the skeleton would be secretly buried and never be available for study. A group of anthropologists went to court to stop the Corps from complying with the tribe's request. The anthropologists claimed that the Umatillas were not in that part of the Northwest when Kcnncwick Man lived; hence, he could not be one of their ancestors. And of course his Caucasoid skeletal features led to the same conclusion. Thus, the available scientific evidence is that Kcnncwick Man was not a Umatillan or any other Native American.
In response to that hypothesis, a leader of the tribe, Armand Min-thorn, stated this position:
Our ciders have taught us that once a body goes into the ground, it is meant to stay there until the end of time.... If this individual is truly over 9,000 years old, that only substantiates our belief that he is Native American. From our oral histories, we know that our people have been part of this land since the beginning of time. We do not believe that our people migrated here from another continent, as the scientists do. ... Scientists believe that because the individual's head measurements do not match ours, he is not Native American. Our elders have told us that Indian people did not always look the way we look today. Some scientists say that if this individual is not studied further, we, as Indians, will be destroying evidence of our history. We already know our history. It is passed on to us through our elders and through our religious practices.
As of early 2001, the matter remains unsettled. Nevertheless the two perspectives—the anthropologists' and the Native Americans'— provide a classic example of two polar points of view that I will analyze throughout this book. One point of view rests on the questions and methods of science. The other rests on cultural beliefs that have been passed down from generation to generation. One side seeks a solution to a problem of intense interest to scientists and historians; the other side docs not recognize that there is a problem that needs a solution.
This dispute over the future of Kcnncwick Man represents a clash between two immiscible patterns of thought. Another example (reported in the New Yor^ Times on August 29, 1997) comes from Afghanistan, where the Taliban, a Muslim sect, have gained control of much of the nation and arc enforcing conformity to the Sharia, sacred Islamic law. According to this code, thieves must be punished by having their hands and feet cut off; couples caught in adulterous acts must be stoned to death; and if women do not cover themselves from head to foot, the young Taliban enforcers deal them a severe flogging. The young zealots have even beaten women for wearing white socks or plastic sandals.
The head of the General Department for the Preservation of Virtue and Prevention of Vice, Alhaj Maulavi Qalamuddin, explains the Taliban point of view: "Some women want to show their feet and ankles. They arc immoral women. They want to give a hint to the opposite sex." This must be controlled to "prevent impure thoughts in men"; "if we consider sex to be as dangerous as a loaded Kalashnikov rifle, it is because it is the source of all immorality." The rules of the Sharia relating to women arc harsh in other respects, by late-twenticth-ccntury standards in the West. Women arc prohibited from working or obtaining an education or even receiving medical treatment, and after puberty they arc almost entirely secluded in their homes.
The ion channels for the keyhole
The cell membrane is a thin layer of lipids, isolated from the outside world in the cell. It maintains the cellular components of crucial importance, it prevents the exchange of soluble molecules. More transport equipment (such as proteins and other) in the cell membrane, and thus communicate with the extra cellular environment. Ion channels in these devices. This membrane forms a physical barrier to cells and allows the components of the cell environment is strictly regulated, so that the ideal conditions for cell metabolism. Membrane, but it also means that as the movement of substances in and out of the pores of the specialized cells are needed. This forms a channel through the membrane is salt (charged atoms and ions) and large molecules such as sugar.
Most of these channels are selective for certain membrane materials and can be opened and closed, and electric garage door remote control or cell keys with chemicals known as ligand.
Some of these channels as a membrane pump, fuel energy in some chemical or other objects. The most studied is the "sodium-potassium ATPase, rather than the revolving door in the membrane and simultaneously spit the plane return to the sodium-potassium. Uvrtiti increase pump 3 sodium ions for potassium ions 2, pulling in the sense that over time, the cells built in the net negative charge in relation to the environment "extra cellular" fluid.
Nerve Cells (Neurons) that this situation is to give information to one hundred and twenty meters per second. This is achieved by ion channels in the cell membrane open at a fraction of a second to a small number of positively charged ions flow of sodium in nerve cells with a loss of nerves called the action potential activity. This action potential travels along the Neuron, and sometimes to the strengthening of other ion channels, which are characterized by electrical activity. Plan nerve and the frequency of action, information very quickly from one body to another.
But what if you have a PIN? How this type of crime? The solution is simple elegance. If the PIN code of the skin, pain perception is determined by the production of action potentials of pressure, nerve fibers in the dermis. Membrane of nerve fibers offer open ion channels permeable to sodium ions postively charged.
The entry of sodium content activated cells, action potentials, nerve fibers in the spinal cord. In spinal cord, signals to other groups of nerve cells that connect with the parts of the brain that provides pain. Information is also transmitted to other nerve cells, muscle groups, leaving the feet. The result is that because of the activity of ion channels, leave PIN Ostrog almost as soon as you feel.
But ion channels is not only to work on the nervous system. Indeed, life can not be first, without family ion channels in action around the time of conception, so that when the sperm fuses with the egg, the electrical properties of the membrane of the egg must be changed to prevent further dissemination of the sperm.
Ion channels also that the pacemaker keeps pace. Each pulse of the movement of calcium ions in myocardial cells through calcium channels. This leads to a rapid release of calcium stores in cells even more (of the second type of calcium channel), which is the heart muscle to beat. Each cell is a type of ion channel instrument to carry out their physiological functions.
Forecasts, given the important role you play in the ion channels in our bodies, many human diseases are caused by the ion channels that does not work. In some cases it is caused by mutations or changes in the genes coding for proteins to ion channels. About a similar problem may occur if the ion channels are proteins in their function is not working. Cystic fibrosis, epilepsy and certain heart rhythm disturbances (arrhythmias), such as "Long KT syndrome are examples of this phenomenon.
There is nothing about genetics, but because of food poisoning bacteria, including the vulnerability of ion channel function by producing toxins that cause diarrhea can be defined by each of the ion channels in cells podstava sets.
All these factors mean that ion channels, especially for therapeutic drugs, for example, during the operation targeted areas of anesthesia and nerve-muscle-blockers in the treatment of neurological and psychiatric disorders, such as' epilepsy and schizophrenia, CARDIAC ion channel drugs that block the heart rate. Surprisingly, most of the substances used are based on random discoveries - something, if we only use the system later. But now we are in a time of "rational" and pharmacologically similar suit measurement is the recipient of the mind.
The idea of ion channels: A little history
Does "ion channels" built in 1950 by the pioneering work of Alan Hodgkin and Andrew Huksley in Cambridge, and Bernard Katz at University College London. It is shown that the movement of sodium and potassium ions, force the action potential in nerve cells, working with the Hodgkin-Huksley a Nobel Prize in 1963. Further work in the1960s and 1970 in various laboratories around the world, leading to the identification of the first ion channel protein: The acetylcholine receptor of electric ray (Torpedo califormica).
Until the early 1970s was not NOK evidence to change, the move is a very minor (some picoamperes, which deals with 1/100-billionth that protječe bulb for desk lamp) must move through each channel. But the "noise" in the methods used in the time it was too big for that electricity sićuušni directly measured.
This change is in the mid-1970s, when German scientists Eruin Neher and Bert Sakmann have managed to measure the flow of ions through various channels with the new techniques are developed. Name "Patch bite", this method is that everywhere in the world, and researchers can use the introduction of ions through the channel and the individual in real time. In recognition of their contribution, the Nobel Prize in Medicine in 1991.
More recent advances in molecular genetics have allowed the cloning of various channels and ion channel properties in the protein sequence, which has been built. Another important breakthrough in 1998, when Roderick MacKinnon who Houard Hughes Medical Institute in the U.S., X-ray crystallography to solve the atomic structure of ion channel - in the bacterial potassium channel KcsA from Streptomyces lividans. Mackinnon was awarded the prize for chemistry in 2003.
But what is the structure of an ion channel?
Ion channel protein molecules symmetrical shrinkage of a water-filled cell membranes: kalijevog crystal structure of the KcsA channel from Streptomyces lividans. Cavities, the bridges in the cell. In some aspects of ion channels can be considered as "excitable molecules, such as a feeling.
Various ion channels so that different sensors to different situations, and therefore different mechanisms for each sensor. Some of them involve changes in membrane potential and is known as voltage-gated ion channels. Other small response to chemical (ligand) that Sveže to certain areas of the protein, called ligand-gated ion channels. Channels, the deformations and stresses in the membrane, such as PIN-link or listen to music is mechanosensors.
Channels or activation response, regardless of the offer, and is used as a time window in a series of molecular movements or changes in the conformation of the protein that opens the pores in the skin. Surprisingly, the ion channels can choose between the ion channels that Wednesday passage may form chloride ions, sodium, while the other. This house is without pores, certain types of ions through the very high rates (up to 106 ions per second), while other flows Kochi. On the basis of selective permeability, such as ion channels kalijev channels, calcium channels, sodium channels and so on.
Study of ion channels in action after another
On the question of ion channels that are open today. What is the molecular motions in the ion channel protein that lead to open the pores and the flow of ions through it? Because the classical biochemical method to measure the average activity of thousands of channels, it is not possible to measure the heterogeneity of the dynamics of movements, in May, which will be the most important aspects of their behavior. To answer this question, you should be able to predict the behavior of ion channels one by one. It is so far only a single channel time clamping recordings. But the test that the transitions between open and closed position, they will not be able to probe structural changes in proteins, which form the basis of the mechanisms for opening and closing. Crystal structures also detailed information about the structure of proteins, but only one of many snapshots of the chain configuration can be taken.
Recent advances in the techniques of fluorescence optical, it is possible to directly observe single molecules (eg ion channels) in action. For opening a new era in biotechnology as a "single molecule nano-Biosciences. An extensive internal reject fluorescence micro copy: Total internal reflection occurs when light rays of the thickness of the media as glass, the interface with less density as water (or cells) in the angle is greater than the critical angle. the light is reflected, but part of the light energy distributed in very small distance the less dense media to generate so-called volatile golf. This is then used to excite the fluorescent display molecules. Given the intensity and resolution of the instability in the area exponentially with distance, only a few nano meters through l sample, it is possible that some molecules. images were videotaped in real time along with a special camera (intensified CCD-camera). This technique is completely reject internal fluorescence (or TIRF) Microscopy, by Daniel Akselrod, University of Michigan in the early 1980's.
Based on the visual appearance of internal complete rejection, this technique allows us to predict the behavior of molecules in real time, and in vitro in living cells. Neon display molecules have been studied, but progress in this area is now possible to almost all fluorescently label biomolecules (including ion channels).
The biggest advantage over any conventional TIRF fluorescence microscope using a special type rasvjete known as reduction of the wave of the lighting comes from the small proportion (around one hundred nano meters) in the sample ad, the cone cells alive. Fluorescence in other parts of the sample (who are not interested in) are rejected, so that the detection of molecules. TIRF Microscopy besprimjernom already understand many cellular processes such as protein folding, enzyme catalysis and protein motors move. Well, many laboratories around the world use technology to ion channels in action.
This is a start, but the procedure is safe, a new light on the activities of membrane minijaturnih devices. And researchers see the same path in the action and simultaneously measuring the ionic current through, this technology promises a new era in ion channel idea!
Most of these channels are selective for certain membrane materials and can be opened and closed, and electric garage door remote control or cell keys with chemicals known as ligand.
Some of these channels as a membrane pump, fuel energy in some chemical or other objects. The most studied is the "sodium-potassium ATPase, rather than the revolving door in the membrane and simultaneously spit the plane return to the sodium-potassium. Uvrtiti increase pump 3 sodium ions for potassium ions 2, pulling in the sense that over time, the cells built in the net negative charge in relation to the environment "extra cellular" fluid.
Nerve Cells (Neurons) that this situation is to give information to one hundred and twenty meters per second. This is achieved by ion channels in the cell membrane open at a fraction of a second to a small number of positively charged ions flow of sodium in nerve cells with a loss of nerves called the action potential activity. This action potential travels along the Neuron, and sometimes to the strengthening of other ion channels, which are characterized by electrical activity. Plan nerve and the frequency of action, information very quickly from one body to another.
But what if you have a PIN? How this type of crime? The solution is simple elegance. If the PIN code of the skin, pain perception is determined by the production of action potentials of pressure, nerve fibers in the dermis. Membrane of nerve fibers offer open ion channels permeable to sodium ions postively charged.
The entry of sodium content activated cells, action potentials, nerve fibers in the spinal cord. In spinal cord, signals to other groups of nerve cells that connect with the parts of the brain that provides pain. Information is also transmitted to other nerve cells, muscle groups, leaving the feet. The result is that because of the activity of ion channels, leave PIN Ostrog almost as soon as you feel.
But ion channels is not only to work on the nervous system. Indeed, life can not be first, without family ion channels in action around the time of conception, so that when the sperm fuses with the egg, the electrical properties of the membrane of the egg must be changed to prevent further dissemination of the sperm.
Ion channels also that the pacemaker keeps pace. Each pulse of the movement of calcium ions in myocardial cells through calcium channels. This leads to a rapid release of calcium stores in cells even more (of the second type of calcium channel), which is the heart muscle to beat. Each cell is a type of ion channel instrument to carry out their physiological functions.
Forecasts, given the important role you play in the ion channels in our bodies, many human diseases are caused by the ion channels that does not work. In some cases it is caused by mutations or changes in the genes coding for proteins to ion channels. About a similar problem may occur if the ion channels are proteins in their function is not working. Cystic fibrosis, epilepsy and certain heart rhythm disturbances (arrhythmias), such as "Long KT syndrome are examples of this phenomenon.
There is nothing about genetics, but because of food poisoning bacteria, including the vulnerability of ion channel function by producing toxins that cause diarrhea can be defined by each of the ion channels in cells podstava sets.
All these factors mean that ion channels, especially for therapeutic drugs, for example, during the operation targeted areas of anesthesia and nerve-muscle-blockers in the treatment of neurological and psychiatric disorders, such as' epilepsy and schizophrenia, CARDIAC ion channel drugs that block the heart rate. Surprisingly, most of the substances used are based on random discoveries - something, if we only use the system later. But now we are in a time of "rational" and pharmacologically similar suit measurement is the recipient of the mind.
The idea of ion channels: A little history
Does "ion channels" built in 1950 by the pioneering work of Alan Hodgkin and Andrew Huksley in Cambridge, and Bernard Katz at University College London. It is shown that the movement of sodium and potassium ions, force the action potential in nerve cells, working with the Hodgkin-Huksley a Nobel Prize in 1963. Further work in the1960s and 1970 in various laboratories around the world, leading to the identification of the first ion channel protein: The acetylcholine receptor of electric ray (Torpedo califormica).
Until the early 1970s was not NOK evidence to change, the move is a very minor (some picoamperes, which deals with 1/100-billionth that protječe bulb for desk lamp) must move through each channel. But the "noise" in the methods used in the time it was too big for that electricity sićuušni directly measured.
This change is in the mid-1970s, when German scientists Eruin Neher and Bert Sakmann have managed to measure the flow of ions through various channels with the new techniques are developed. Name "Patch bite", this method is that everywhere in the world, and researchers can use the introduction of ions through the channel and the individual in real time. In recognition of their contribution, the Nobel Prize in Medicine in 1991.
More recent advances in molecular genetics have allowed the cloning of various channels and ion channel properties in the protein sequence, which has been built. Another important breakthrough in 1998, when Roderick MacKinnon who Houard Hughes Medical Institute in the U.S., X-ray crystallography to solve the atomic structure of ion channel - in the bacterial potassium channel KcsA from Streptomyces lividans. Mackinnon was awarded the prize for chemistry in 2003.
But what is the structure of an ion channel?
Ion channel protein molecules symmetrical shrinkage of a water-filled cell membranes: kalijevog crystal structure of the KcsA channel from Streptomyces lividans. Cavities, the bridges in the cell. In some aspects of ion channels can be considered as "excitable molecules, such as a feeling.
Various ion channels so that different sensors to different situations, and therefore different mechanisms for each sensor. Some of them involve changes in membrane potential and is known as voltage-gated ion channels. Other small response to chemical (ligand) that Sveže to certain areas of the protein, called ligand-gated ion channels. Channels, the deformations and stresses in the membrane, such as PIN-link or listen to music is mechanosensors.
Channels or activation response, regardless of the offer, and is used as a time window in a series of molecular movements or changes in the conformation of the protein that opens the pores in the skin. Surprisingly, the ion channels can choose between the ion channels that Wednesday passage may form chloride ions, sodium, while the other. This house is without pores, certain types of ions through the very high rates (up to 106 ions per second), while other flows Kochi. On the basis of selective permeability, such as ion channels kalijev channels, calcium channels, sodium channels and so on.
Study of ion channels in action after another
On the question of ion channels that are open today. What is the molecular motions in the ion channel protein that lead to open the pores and the flow of ions through it? Because the classical biochemical method to measure the average activity of thousands of channels, it is not possible to measure the heterogeneity of the dynamics of movements, in May, which will be the most important aspects of their behavior. To answer this question, you should be able to predict the behavior of ion channels one by one. It is so far only a single channel time clamping recordings. But the test that the transitions between open and closed position, they will not be able to probe structural changes in proteins, which form the basis of the mechanisms for opening and closing. Crystal structures also detailed information about the structure of proteins, but only one of many snapshots of the chain configuration can be taken.
Recent advances in the techniques of fluorescence optical, it is possible to directly observe single molecules (eg ion channels) in action. For opening a new era in biotechnology as a "single molecule nano-Biosciences. An extensive internal reject fluorescence micro copy: Total internal reflection occurs when light rays of the thickness of the media as glass, the interface with less density as water (or cells) in the angle is greater than the critical angle. the light is reflected, but part of the light energy distributed in very small distance the less dense media to generate so-called volatile golf. This is then used to excite the fluorescent display molecules. Given the intensity and resolution of the instability in the area exponentially with distance, only a few nano meters through l sample, it is possible that some molecules. images were videotaped in real time along with a special camera (intensified CCD-camera). This technique is completely reject internal fluorescence (or TIRF) Microscopy, by Daniel Akselrod, University of Michigan in the early 1980's.
Based on the visual appearance of internal complete rejection, this technique allows us to predict the behavior of molecules in real time, and in vitro in living cells. Neon display molecules have been studied, but progress in this area is now possible to almost all fluorescently label biomolecules (including ion channels).
The biggest advantage over any conventional TIRF fluorescence microscope using a special type rasvjete known as reduction of the wave of the lighting comes from the small proportion (around one hundred nano meters) in the sample ad, the cone cells alive. Fluorescence in other parts of the sample (who are not interested in) are rejected, so that the detection of molecules. TIRF Microscopy besprimjernom already understand many cellular processes such as protein folding, enzyme catalysis and protein motors move. Well, many laboratories around the world use technology to ion channels in action.
This is a start, but the procedure is safe, a new light on the activities of membrane minijaturnih devices. And researchers see the same path in the action and simultaneously measuring the ionic current through, this technology promises a new era in ion channel idea!
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