Wednesday, April 28, 2010

The difference between genetically similar and genetically identical

Carl Zimmer explains why two organisms can be genetically similar and yet very different:
Fifth, the oft-cited 98% figure for shared DNA is less impressive than it looks. Most DNA is unused, so natural selection never changes it. Another big chunk of your personal DNA controls the basics of earthly carbon-based life, and is extremely common across multitudinous organisms. Thus, one study found we share 70% of our DNA with yeast! Perhaps if you don't have a great ape around, you can scrape by letting a packet of Fleischmann's Quick-Rise pinch-hit as your role model. De Waal's statement that a chimp is as genetically similar to a human as a fox is to a dog may be true, but it should remind us of the striking number of gene-driven differences seen merely among dog breeds. A collie is identical to a pit bull in all but a tiny fraction of its genes, yet the two breeds differ radically in size, shape, behavior, mentality, and personality. Small genetic differences can have big consequences.

This also holds true for humans where genetic research shows that we share over 99% of our DNA and yet there are great biological differences between the various racial and ethnic groups.

Related:

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