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What most people know about the inheritance of eye color is that brown comes from a dominant gene (needing one copy only) and blue from a recessive gene (needing two copies). University of Queensland geneticist Rick Sturm suggests that the genetics are not so clear. “There is no single gene for eye color,” he says, “but the biggest effect is the OCA2 gene.” This gene, which controls the amount of melanin pigment produced, accounts for about 74 percent of the total variation in people’s eye color.
Sturm has recently shown that the OCA2 gene itself is influenced by other genetic components. After gene-typing about 3,000 people, Sturm found that how OCA2 is expressed—and how much pigment a person has—is strongly linked to three single nucleotide polymorphisms (SNPs), or single letter variations, in a DNA sequence near the OCA2 gene. That suggests a more complicated story than the blue-recessive/brown-dominant model of eye color. “For example, among individuals carrying the SNP sequence “TGT” at all three locations on both copies of the gene, 62 percent were blue-eyed,” says Sturm’s colleague David Duffy. By contrast, only 21 percent of individuals carrying only one TGT copy at each location and 7.5 percent of those lacking the TGT entirely had blue eyes.
Depending on the particular combination of SNPs inherited, a person can have a range of OCA2 activity that lands them on the spectrum between blue and brown eyes. What about green eyes? “Green eyes probably represent the interaction of multiple variants within the OCA2 and in other genes, including perhaps the red-hair gene,” Duffy says.
说白了就是没研究出来100%的 眼睛颜色的决定因素。 还在研究，这就是master， doctor， 为什么没完没了的天天做research。 这么多活都没研究出来，还不赶紧干。快研究，我等信儿呢！ |
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楼主
终于我明白了，眼睛就是个调色板。 基因决定了颜料。 科学家研究出了调色原理，但是没研究明白决定基因。希望他们加油，努力。
