Universität Mainz. "Natural selection has altered the appearance of Europeans over the past 5,000 years." ScienceDaily. ScienceDaily, 10 March 2014. <www.sciencedaily.com/releases/2014/03/140310182731.htm>.
Anthropologists at Johannes Gutenberg University Mainz, geneticists at University College London, and archaeologists from Kiev and Berlin have been working together to get a better idea of the evolution of the human race over the past 50,000 years. To do this, they have been studying the DNA of ancient skeletons in Europe, and have then been comparing the data gained from this to the genomes of today's Europeans. Through their research, they have determined that over the last 50,000 years, change in eye, hair, and skin pigmentation has occurred in Europeans (possibly in the humans of other locations as well, though research of this was not posted in this media file). According to the DNA of the skeletons studied, the skin, hair, and eye color of Europeans used to be darker. The reason for the change to a lighter skin pigmentation may have been due to the migration of Europeans to more northern latitudes throughout the last 50,000 years. This would have caused for lighter skin pigmentation to be favored because of the decrease in sunlight in the north meaning that it would be more difficult to receive vitamin D. Lighter skin pigmentation allows for it to be simpler to gain vitamin D. According to this media blog, the reason for lighter hair and eye color pigmentation may have been due to sexual selection. If Europeans favored lighter hair and eye color (which is likely due to segregation), then it would only make sense that Europeans would want to have a husband or wife with lighter hair and eye color meaning that the genes for these traits would likely be passed down from generation to generation.
This relates to our learning of evolution that we are currently doing in class. In class, we learned that the beaks of finches that lived on the Galapagos Islands have been changed (due to natural selection) to help the finches better survive in their environment. The evolution of human skin color is very similar in the fact that natural selection was used to allow humans to better survive in their new environment located further north. The sexual selection that affected human eye and hair color is similar to the sexual selection that we learned about relating to the peacock spiders that dance to attract a mate. Similar to the peacock spider, if a human does not contain attractive qualities, then they may not find a mate causing for their unsuccessful traits to not be passed on (except the spider also gets eaten) decreasing the amount of unsuccessful (not attractive) genes in the gene pool of the Europeans making it less likely that these darker genes will remain. This then caused for an overall change in the eye color and hair color of Europeans similar to the change that would take place with the spiders.
Were there other possible reasons for the change in skin pigmentation from darker to lighter besides the migration of Europeans to more northern latitudes?
ReplyDeleteThe media file said that the lack of sunlight caused due to migration was likely the main reason for lighter skin color, but the file also said that another possibility was that the average skin color became lighter due to sexual selection (similiar to the eye and hair color).
DeleteHaving lighter colored hair, eyes, and skin would help gain more vitamin D; but what can vitamin D help with, what is it used for? How much of it do we need for our daily lives to the point where we would need lighter skin to help obtaining it?
ReplyDeleteVitamin D is used to generally used to treat weakened bones and help muscles move. The suggested amount of vitamin D for teenagers is 600 IU and it is likely that the body will do whatever it needs to do to help maintain its bones and muscle movement. At the time when skin turned to a generally lighter color, it may have been possible that the bodies of people had very low amounts of vitamin D, causing for their bodies to do whatever needed to get more vitamin D to preserve their bones and muscle movement.
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