Single Nucleotide Polymorphisms Responsible for Human Eye Color Differences

Posted on December 20, 2006

The BBC reports that genetic scientifics have discovered that just a few letters of the six billion contained the human genetic code are responsible for eye color.

Differences in eye colour are largely down to "single nucleotide polymorphisms" (SNPs - pronounced "snips"); variations in the sequence of letters that make up a single strand of human DNA.

SNPs represent a change of just one letter in the genetic sequence. These changes, or mutations, in our DNA can have important consequences for how the gene gets physically expressed.

All the SNPs are located near a gene called OCA2. This gene produces a protein that helps give hair, skin and eyes their colour. And mutations in OCA2 cause the most common type of albinism.

According to the study there is not a specific gene for eye color instead it is the combination of these SNPs that results in different eye colors. Dr. Richard Sturm from the University of Queensland - one of the scientists who discovered the SNPs - said that "The SNPs we've identified in themselves are not functionally causing the eye colour change, but they are linked very, very closely to something that is."

This early genetic work determining how the genome helps determine things like eye and hair color is significant because it could be a major stepping stone to more significant genetic findings.

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