Thursday, August 02, 2018

Pleiotropic genes

A brief exchange I had on Facebook:

Dennis Venema recently claims that one evidence for whale evolution is "genes for air-based olfaction (smelling) in whales that no longer even have olfactory organs." Other questions aside, does each gene have a single function, or can the same gene have multiple functions?

My point, of course, is that if the same gene can perform two or more functions, then the fact that some animals have a gene with a "useless" function, that doesn't entail that it derives from a distant ancestor which had that function, viz. land mammals to marine mammals. For the same gene may have another useful function.

That's a very good question. Many genes are pleiotropic i.e. they have multiple functions. I wasn't sure whether that was the case for odorant receptors but this paper suggests that they are present elsewhere as well: 

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