2006 National DNA Day Online Chatroom Transcript
This is just one question from an archive of the National DNA Day Moderated Chat held in April 2006. The NHGRI Director and many genomics experts from across NHGRI took questions from students, teachers and the general public on topics ranging from basic genomic research, to the genetic basis of disease, to ethical questions about genetic privacy.
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Why doesn't everyone look alike if we only have a 1 percent difference in our genes?
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Bill Gahl, M.D.: In a way, we do all look alike, and a lot different from, say, sheep. But I like to think of our variable appearances as related to pathways. Suppose it takes a pathway of 100 steps in development to make a nose. (It probably takes many times that.) If two people differ in just one of those 100 steps (i.e., 1% of the genes are different in the two individuals), the nose will look different. Now make a slightly different size of cheekbone, a slightly different color and shape of the eyes, etc., and you have two people who look quite different.
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