![]() ![]() In addition, hair and eye color is most diverse in what used to be, when first peopled by hunter-gatherers, a unique ecozone of low-latitude continental tundra. Sexual selection is particularly indicated because it is known to favor color traits and color polymorphisms. The many allèles involved (at least seven for hair color) and their independent origin over a short span of evolutionary time indicate some kind of selection. Human hair and eye color is unusually diverse in northern and eastern Europe. We show that the frequency of the derived allele at Y182H is significantly correlated with lower solar radiation intensity inEast Asia and infer that MFSD12 was under selection in East Asians, probably after their split from Europeans. ![]() Strongest association with skin pigmentation at 19p13 was observed for anY182H missense variant (common only in East Asians and Native Americans) in MFSD12, a gene recently associated with skin pigmentation in Africans. We demonstrate the presence of multiple independent signals of association in the 11q14 and 15q13 regions (comprising the GRM5/TYR and HERC2/OCA2 genes, respectively) and several epistatic interactions among independently associated alleles. These include one novel locus for skin pigmentation (in 10q26) and three novel loci for eye pig-mentation (in 1q32, 20q13 and 22q12). We found eighteen signals of association at twelve genomic regions. We report a genome-wide association scan in >6,000 Latin Americans for pigmentation of skin and eyes. Intense male-male competition may explain increased masculinization of body build in highly polygynous agricultural populations of sub-Saharan Africa. Intense female-female competition may explain an unusual convergence of color traits in northern and eastern Europeans. Because mate competition has varied in intensity among human populations, sexual selection has correspondingly varied in intensity for certain traits, often highly visible and colorful ones. This means of subsistence allowed women to become primary food producers, thereby freeing men to take more wives. Conversely, men competed the most for mates in the Tropics, particularly after year-round agriculture emerged. Women competed the most for mates in the 'continental Arctic,' where wandering herds were the main food source. The longer the winter, the costlier it became to provision a second wife and her children, since women could not gather food in winter. Men were less available because they 1) hunted over longer distances that increased male mortality proportionately and 2) were less able to offset the resulting man shortage through polygyny. Although this type of environment is now fragmentary, it covered until 10,000 years ago a much larger territory-the same area where, today, hair and eyes are diversely colored and skin almost milk white.Īmong early modern humans, a woman would face stronger competition for a mate the further away she was from the equator. It was strongest on continental steppe-tundra, where men provided for almost all family food needs by pursuing herds of reindeer and other herbivores over long distances. Sexual selection of women was stronger at latitudes farther from the equator, where men were less polygynous and more at risk of death while hunting. Among early modern humans, such imbalances resulted from 1) a low polygyny rate (because few men could provide for a second wife and her children) and 2) a high risk of early male death (because long hunting distances increased exposure to environmental hazards). Sexual selection will target women if they outnumber men on the mate market. Such selection is consistent with 1) the many alleles for European hair and eye color 2) the high ratio of nonsynonymous to synonymous variants and 3) the relatively short time over which this color diversity developed. It favors eye-catching colors and, if strong enough, can produce a color polymorphism, i.e., whenever a visible feature becomes differently colored through mutation, the new color will spread through the population until it loses its novelty value and becomes as frequent as the original one. This color scheme is more developed in women than in men and seems to have been selected for its visual properties, particularly brightness and novelty. Their skin is pale, almost like an albino’s. Their hair can be not only black but also brown, flaxen, golden, or red, and their eyes not only brown but also blue, gray, hazel, or green. Europeans, particularly northern and eastern Europeans, are unusually colored. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |