In the gene pool...but when?

Question

I believe from what I've read that when a parent has a child the parent's genes increase in frequency in the human gene pool.

Let's imagine that the father had the sole copy of an ancient gene. By passing it on to his son the frequency would be doubled from 1 to 2 - right?

If so, here is my question: WHEN does the gene copy enter to pool - at conception, during fetal development, at the birth of the child, or later still, maybe at sexual maturity?

Answer 1

The *frequency* is the *percentage* of the population that have the gene. There are 6 billion people on the planet.

So if a father had the sole copy of a gene and passed it to his son ... the frequency would increase from 1-out-of-6-billion (0.00000000017%) ... to 2-out-of-6-billion (0.00000000033%) ... which is an insignificant increase in frequency (it is indeed a doubling ... but a doubling of an already infinitessimally small number). In other words, it can barely be considered part of the human "gene pool" at all.

But to answer your question, technically this occurs the moment there is another individual with that gene ... which is the moment of conception of his son.

(Incidentally, we should more correctly be talking about the frequency of the *allele*, not the frequency of the gene ... but I think we all get the idea.)

Answer 2

Your logic is in violation of the Geneva rules against torture.

First gene frequency is per generation, not having a child would lower the frequency by one, but having a child would only count if the gene was passed on, and that is only a 50% probability..

Second if the gene was passed on to one child, that would make the situation static, no more no less of the gene.

Third if there were two children with the gene that would not double the frequency unless the original father was the only one.

Fourth if the gene is indeed ancient then it would not very likely be the only case. If you are talking about more than 30 generations, then any family tree has a trillion possible ancestors, obviously way more than the total earth population, so that ancient ancestor would show up multiple times in any individual with the remotest possibility of having that ancestor.

As a result any person would only differ from another in the number of times that ancestor showed up, rather than not showing up at all. The frequency of that gene would be the percentage of times the ancestor showed up, against a 50% probability that the gene would be passed on each time, times the total population of descendants.

So a very old gene would be widely spread in the population and one individual having one or two children with the gene would make only a small difference.

As the gene frequency would be measured in the entire population, in a few dozen generations again every single living person would have every person who had children thirty generations earlier as an ancestor. So a gene pool is just that, a pool of all the genes of everyone alive in that generation, and only statistically relevant to any individual .

Answer 3

At sexual maturity I suppose... although the gene may mutate as it is passed so there may not be 2 copies after all.

Answer 4

technically, your fathers gene entered the pool at fertilization. however, there wouldn't really be any effect until the son grew up and did the same. this is because if the son is sterile or never has kids, the effective change in the gene pool is none (remains at one).

Answer 5

conception. the genes are added together, genes are in both sex cells (the egg and sperm) are put together, no genes, no kid, and the ancient gene thing depends.

Answer 6

of course , as dna proves we all have a common ancestor.