I think skin color is the most common thing that people talk about when they are having a conversation about race or racism, followed by religion. I’ve noticed that most cultures around the world place an importance on skin color. (North Americans, South Americans, Europeans, Indians, Chinese, Japanese, Ect.) Scientific studies have shown that people with lighter complexions tend to have more privileges within their society. Humanity has been conditioned to prefer the appearance of people with lighter complexions.
There are many theories to explain why this has happened. Some people believe that racism exist today because albinos were shunned from our society in Africa thousands of years ago. There is a theory that they were forced to migrate out of Africa because of the poor treatment that they received from the Africans with darker complexions. The white skinned Africans did not let their children forget about the way that they were treated, and that is the reason why skin color has been such a big issue in our society for thousands of years. I guess there could some truths to that theory.
I am going to post an excerpt from a book that is called DNA The Secret Of Life. It was written by James D. Watson and Andrew Berry. James D. Watson was the first director of the National Center for Human Genome Research of the National Institutes of Health from 1989 to 1992. He won a Nobel Prize for physiology and medicine in 1962. Andrew Berry has a Ph.D. in fruit fly genetics. He is a research associate of Harvard University’s Museum of Comparative Zoology.
Excerpt from chapter 9 Out Of Africa
Because of the short evolutionary timescales involved, most of the consistent differences we do see among groups are probably products of natural selection: skin color, for one.
Under their dense matted hair, the skin of our closest relatives, the chimpanzee, is largely unpigmented. (Chimpanzees you might say, are white.) And presumably the common ancestor of chimpanzees and humans from which the human lineage spun off five million years ago was similar. And so we infer that the heavy skin pigmentation characteristic of Africans (and of the earliest modern humans, in Africa born) arose in the course of subsequent human evolution. With the loss of body hair, pigment became necessary to protect skin cells from the sun’s damaging ultraviolet (UV) radiation. We know at a molecular level how UV rays can cause skin cancer: they make the thymine bases of the double helix stick to one another, creating a kink, so to speak, in the DNA molecule. When that DNA replicates itself, this kink often promotes the insertion of a wrong base, producing a mutation. If, by chance, that mutation is in a gene that regulates patterns of cell growth, cancer may result. Melanin, the pigment produced by skin cells, reduces UV damage. As anyone with a hopelessly fair complexion as mine knows too well, sunburns, though typically not lethal, can be a much more immediate health threat than skin cancer. Thus it is easy to imagine natural selection favoring the acquisition of dark skin in order to prevent not only cancer, but also infections that can easily result from a severe sunburn.
Why did people living in higher latitudes lose melanin? The best explanation involves vitamin D3 synthesis, a process carried out in the skin and requiring UV light. D3 is essential fro calcium uptake, which in turn is a critical ingredient of strong bones. (A deficiency of D3 can result in rickets and osteoporosis.) It is possible that, as our ancestors moved out of Africa into highly seasonal environments, with less year-round UV radiation, natural selection favored pale-skinned variants because they, with less sun-blocking pigment in their skin, synthesized D3 more efficiently with the limited UV available. The same logic may apply to the movements of our ancestors within Africa. The San, for instance in South Africa, where UV intensities are similar to those of the Mediterranean, have a strikingly pale skin. But what about the Inuit peoples, who live in or close to the hardly sunny arctic but are surprisingly dark? Their opportunities for producing the vitamin would appear to be further limited by the need to be fully clothed all the time in their climate. In fact, the selective pressure favoring lightness seems not to have asserted itself among them, and the reason appears to be that they have solved the D3 problem in their own way: a diet with plenty of fish, a rich source of the essential nutrient.
Given what a powerful determinant, mostly for ill, skin color has been in human history and individual experience, it is surprising indeed how little we know about its underlying genetics. This deficit, however, may have less to do with the limitations of our science and more with the intrusion of politics into science; in an academic world tyrannized by political correctness, even to study the molecular basis of such a characteristic has been something of a taboo. What little we understand about it depends on old studies of mixed-race children, which established that several genes contribute to pigmentation. But our knowledge of other species and the similarity of basic biochemical processes among all mammals suggest a more complicated picture. We know, fro instance, that may genes affect coat color in mice, and it is likely that these have direct human equivalents. So far though, we have managed to identify only two genes involved in human pigmentation: that one that, when mutated, causes albinism, and the other, the “melanocortin receptor”, associated with red hair and a pale (often freckled) complexion. The melancortin receptor gene is variable among Europeans and Asians, but invariant among Africans, suggesting that there has been strong natural selection in Africa against mutations in the gene, i.e.; against red-haired, fair-skinned individuals. Albinos, who lack pigment altogether, occasionally appear today in African populations (probably through de novo mutation) but their acute sensitivity to sunlight puts them at a severe disadvantage.
There are many theories to explain why this has happened. Some people believe that racism exist today because albinos were shunned from our society in Africa thousands of years ago. There is a theory that they were forced to migrate out of Africa because of the poor treatment that they received from the Africans with darker complexions. The white skinned Africans did not let their children forget about the way that they were treated, and that is the reason why skin color has been such a big issue in our society for thousands of years. I guess there could some truths to that theory.
I am going to post an excerpt from a book that is called DNA The Secret Of Life. It was written by James D. Watson and Andrew Berry. James D. Watson was the first director of the National Center for Human Genome Research of the National Institutes of Health from 1989 to 1992. He won a Nobel Prize for physiology and medicine in 1962. Andrew Berry has a Ph.D. in fruit fly genetics. He is a research associate of Harvard University’s Museum of Comparative Zoology.
Excerpt from chapter 9 Out Of Africa
Because of the short evolutionary timescales involved, most of the consistent differences we do see among groups are probably products of natural selection: skin color, for one.
Under their dense matted hair, the skin of our closest relatives, the chimpanzee, is largely unpigmented. (Chimpanzees you might say, are white.) And presumably the common ancestor of chimpanzees and humans from which the human lineage spun off five million years ago was similar. And so we infer that the heavy skin pigmentation characteristic of Africans (and of the earliest modern humans, in Africa born) arose in the course of subsequent human evolution. With the loss of body hair, pigment became necessary to protect skin cells from the sun’s damaging ultraviolet (UV) radiation. We know at a molecular level how UV rays can cause skin cancer: they make the thymine bases of the double helix stick to one another, creating a kink, so to speak, in the DNA molecule. When that DNA replicates itself, this kink often promotes the insertion of a wrong base, producing a mutation. If, by chance, that mutation is in a gene that regulates patterns of cell growth, cancer may result. Melanin, the pigment produced by skin cells, reduces UV damage. As anyone with a hopelessly fair complexion as mine knows too well, sunburns, though typically not lethal, can be a much more immediate health threat than skin cancer. Thus it is easy to imagine natural selection favoring the acquisition of dark skin in order to prevent not only cancer, but also infections that can easily result from a severe sunburn.
Why did people living in higher latitudes lose melanin? The best explanation involves vitamin D3 synthesis, a process carried out in the skin and requiring UV light. D3 is essential fro calcium uptake, which in turn is a critical ingredient of strong bones. (A deficiency of D3 can result in rickets and osteoporosis.) It is possible that, as our ancestors moved out of Africa into highly seasonal environments, with less year-round UV radiation, natural selection favored pale-skinned variants because they, with less sun-blocking pigment in their skin, synthesized D3 more efficiently with the limited UV available. The same logic may apply to the movements of our ancestors within Africa. The San, for instance in South Africa, where UV intensities are similar to those of the Mediterranean, have a strikingly pale skin. But what about the Inuit peoples, who live in or close to the hardly sunny arctic but are surprisingly dark? Their opportunities for producing the vitamin would appear to be further limited by the need to be fully clothed all the time in their climate. In fact, the selective pressure favoring lightness seems not to have asserted itself among them, and the reason appears to be that they have solved the D3 problem in their own way: a diet with plenty of fish, a rich source of the essential nutrient.
Given what a powerful determinant, mostly for ill, skin color has been in human history and individual experience, it is surprising indeed how little we know about its underlying genetics. This deficit, however, may have less to do with the limitations of our science and more with the intrusion of politics into science; in an academic world tyrannized by political correctness, even to study the molecular basis of such a characteristic has been something of a taboo. What little we understand about it depends on old studies of mixed-race children, which established that several genes contribute to pigmentation. But our knowledge of other species and the similarity of basic biochemical processes among all mammals suggest a more complicated picture. We know, fro instance, that may genes affect coat color in mice, and it is likely that these have direct human equivalents. So far though, we have managed to identify only two genes involved in human pigmentation: that one that, when mutated, causes albinism, and the other, the “melanocortin receptor”, associated with red hair and a pale (often freckled) complexion. The melancortin receptor gene is variable among Europeans and Asians, but invariant among Africans, suggesting that there has been strong natural selection in Africa against mutations in the gene, i.e.; against red-haired, fair-skinned individuals. Albinos, who lack pigment altogether, occasionally appear today in African populations (probably through de novo mutation) but their acute sensitivity to sunlight puts them at a severe disadvantage.
