Re: Bad Bad Bad
There is a major genetic choice being made here.
When DNA is replicated there is a small, predictable error rate in the transcription. Repeated duplication causes the errors to accumulate. For this reason Nature has opted to have some future genetic material be produced very early in embryo development. Eggs are relatively low in number and are not created later in life.
Sperm however, have to perform a difficult feat; Reach the egg and fuse with it. The two cells are separated by large cellular distances, so vast numbers of mobile sperm are highly desirable. Thus sperm must be produced as needed thruout life, and will contain many faulty gene sets.
The 'ordeal by long-swim' makes sure that obviously faulty sperm have no chance. It's not perfect, but the rate of bad male genes is greatly reduced.
It's really not a good idea to be messing with so basic a process, but we do it all the time anyway. I myself have bad eyes, which normally would be weeded out of the gene pool. Lucky me!
Biting the hand that feeds IT
