2010 National DNA Day Online Chatroom Transcript
This is just one question from an archive of the National DNA Day Moderated Chat held in April 2010. 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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If someone has one blue eye and one brown eye, is this codominance or a mutation?
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David Adams, M.D., Ph.D.:
David Adams studies rare inborn errors of metabolism and other rare genetic syndromes to understand the disease process and identify potential treatments.
For an 9th grader, you have had some great genetics education. Good work! So, as you may know, co-dominance describes a condition where two traits can both be seen in the same individual. An example is where a white flower and a red flower are crossed to make a pink flower. This term is fairly seldom used for humans, but it could be. A mutation in humans is where the DNA has a change that causes a phenotype (for instance a disease or change in eye color). So, DNA changes (mutations) can cause eye color changes. Usually, they are not co-dominant but epistatic (one, say brown, replaces another, say blue). Different eye colors in the same person can be caused by other mechanisms like mosaicism (differences in the genes between two parts of the body) and some medical conditions like Waardenburg syndrome. |
| Westview High School in CA (9th grade student) |
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