If you pick up a genetics textbook anywhere you can study about selection against a recessive or dominant trait. If it were dominant there would be no homosexuality; if it were recessive it would be as common as albinism, or 1 in 5,000 instead of 1 in 20.
I'm sorry but you really are in correct there I have to say. In the case of one recessive gene the odds on expression are 3:1 (dominant : recessive), the odds for characteristics requiring two recessive genes are 15:1 (9:3:3:1 (DD, DR, RD, RR)) . for charecteristics requiring the expression of more than two recessive genes the odds go up in an exponetial manner
Well, I am pretty sure I am wasting my time but here goes. Hitler wanted to create a blonde hair blue eyed population of humans. Both of those are recessive homozygous traits, meaning that they are each the expression of 2 recessive genes being paired together. In any pairing of genes there can be three solutions: 2 dominant genes, 1 dom and 1 rec, or 2 rec. Dominant is always expressed over recessive. Brown hair and brown eyes are dominant. So if you breed 2 people with brown hair and brown eyes you can have a blonde haired blue eyed child because both of the parents could have been carrying both genes but only expressing the brown ones because they are dominant. Now that that is out of the way on to selection. If we select against the dominant i.e. shoot all people with brown hair or brown eyes, all we will have left will be blue eyed blonde haired people. Their children will be blonde haired and blue eyed forever and on and on. Now if we do the reverse and shoot all the blonde hair blue eyed people we will be left with only brown haired brown eyed people but some of their children will always have blonde hair or blue eyes because the gene was hidden as it was paired with the dominant. But they will become less and less frequent and it is virtually impossible to remove from the gene pool, but will become very rare.
understand now?
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