Clear, Molecular View of How Human Color Vision Evolved

"Clear, Molecular View of How Human Color Vision Evolved." FARS News Agency 19 Dec. 2014. Global Issues in Context. Web. 11 Jan. 2015.

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Summary

It took the ancestors of humans dozens of millions of years to see the rainbow. Just 90 million years ago, our ancestors had a dim vision, seeing UV rays and mainly the color red. They had a bichromatic view of the world. By 30 million years ago, we could see the color blue, but lost our ability to see UV light. This common ancestor lead to gorillas and chimpanzees having the same vision as humans. For some species, the change to blue colored vision came easily. For example, the scabberedfish only needed one mutation to need the change. Our primate ancestors needed seven genetic mutations, in a particular order, to change from UV to blue light. This slow evolution is caused by a lack of environmental change.

There are 5040 ways that the amino acids could have been changed to be able to see blue light. But, 80% of the paths to seeing blue light had non-functioning proteins. This was due to the fact that if one mutation came first, then it would cut off the necessary water supply to the protein. Our ancestors used only one of the remaining 252 pathways to seeing blue light. This lead the researchers to identifying the three amino acid changes that allowed our ancestors to see green.

Relevance

In class we have learned about evolution, and how monkeys and humans share a common ancestor. This article discusses our common ancestor that evolved to see the way we do now. Also, one problem Darwin had with evolution, was the complexity, as he sayed in sixth chapter of On The Origin of Species "To suppose that the eye, with all its inimitable contrivances for adjusting the focus to different distances, for admitting different amounts of light, and for the correction of spherical and chromatic aberration, could have been formed by natural selection, seems, I freely confess, absurd in the highest possible degree." This article states one piece of the puzzle of how our eye evolved to be so complex, and that small changes and simple mutations over millions of years lead to complex changes. This article discusses how over millions of years, natural selection comes into play, causing evolution. It also states that environmental change speeds up evolution. All in all, this article talks about our new unit, and brings up some information from our last unit.

by Gus Teran