Genetics Question

Genetics as it applies to evolution, molecular biology, and medical aspects.

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Genetics Question

Post by sweetspottina » Thu Apr 26, 2007 1:52 am

If a brother and sister were born of a brother and sister, what would their DNA look like? Would it be totally obvious that there was multiple generations of incest? I'm a mystery writer. Please answer in layman's terms! Give me just enough technical info that it sounds like I know what I'm talking about! Thanks to any and all who take the time to help. :D

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Post by MrMistery » Thu Apr 26, 2007 2:44 pm

A brother and a sister are not genetically identical, their genes are more or less 50% identical.
So, to answer your question: NO, it would not be obvious. Though both the brother and the sister in the last generation would show an abnormal percentage of homozygous recessive genes, indicating that there has been inbreeding in the family tree, there is no direct way to detect wether their parents were brothers or not.
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Post by Darby » Fri Apr 27, 2007 3:02 pm

It seems like they would share more loci (DNA tests compare small standard bits - loci - of our chromosomes, magnified with Polymerase Chain Reaction) than straight siblings, enough to indicate the relationship at least, but I'm not sure of that.

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