Why did blue eyes proliferate?

[J.C.MacSwell]

1 hour ago, CharonY said:

Just very quickly and generally (not really specific to the trait in question). We can start at the locus (site) of the mutation that provides the trait of interest and then look at the surrounding regions, which presumably are not under the same selective pressures. If the mutation arose in different persons independently, we would expect to see some variations in those surrounding areas (think of it as different persons providing different backgrounds for the mutation).

Blue eyes arose likely not due to a mutation in a  gene associated with eye color (OCA2)  but in an upstream regulatory element. The interesting bit is that the surrounding area is also conserved in all (tested) folks with blue eyes suggesting that they all share a common ancestor providing this mutation. However, as this analysis relies on testing of folks who are still alive, it obviously cannot tell us if there had been other mutations with the same phenotype or even independent cases of the same mutations.

I.e. we can say all currently living folks with blue eyes (who have been tested) have the same common ancestor, we we cannot say that there were no other cases of blue eyes in the past.

Thanks

 

2 hours ago, Peterkin said:

I can't remember what specifically prompted my response and don't consider it important enough to search for.

 

Okay. I thought you might have been replying to my post since you quoted it, and in the context of my post it was pretty ambiguous to say the least.

[Peterkin]

2 hours ago, J.C.MacSwell said:

I thought you might have been replying to my post since you quoted it, and in the context of my post it was pretty ambiguous to say the least.

I'm sure you're right.