Tuesday, May 09, 2006

The 99.9% vs 0% paradox

: I would agree that this data does seem to suggest that poymorphisms are : higher than the low percentage that I stipulate.  But are these alleles : chosen at random?   I don't see anything here that conclusively demonstrates : that they were.  Do you?

No - almost certainly they were not.  The very fact that they often use protein electrophoresis indicates that they were not.  However since they are studies of genetic variability I doubt they deliberately chose highly variable loci.  Indeed, I expect the opposite.  By picking genes with corresponding proteins, they will be choosing highly fixed areas of the genome (selection will act to preserve the fuction of these regions).  Also - by /only/ examining the resulting proteins, much of the neutral variation in the genome will be being discarded.

Think about what the results being biased the other way would! require: researchers who deliberately seek out genes that are highly variable through coding for parasite-resistance properties?  Deliberately sampling from regions of junk DNA?

: And if you do then how do you rectify this with : the notion that 1 in 1900 alleles are thought to be polymorphic?

1 in 1900 single-locus polymorphisms were cited, I believe - so no reconciliation appears to be required. -- __________  |im |yler  Index of my domains: @iname.com


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