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Mars
20-12-15, 12:08
Have your say about this question. If a family belonging to population X receives gene flow from a population Y - a single admixture event, i.e. somebody mating with someone belonging to the main population at a certain moment in time - how will component Y dilute in the next generations?
Let's say guy from population Y carries 70% genetic component Y, and his wife 100% genetic component X.
Then their offspring mate with people of population X only. I'd like to know the rate of dilution of component Y through time.

Sile
20-12-15, 19:22
Have your say about this question. If a family belonging to population X receives gene flow from a population Y - a single admixture event, i.e. somebody mating with someone belonging to the main population at a certain moment in time - how will component Y dilute in the next generations?
Let's say guy from population Y carries 70% genetic component Y, and his wife 100% genetic component X.
Then their offspring mate with people of population X only. I'd like to know the rate of dilution of component Y through time.

if there is only mixing of this family of X and Y population, then between the 6th and 8th generation, the "invading" mixture will have disappeared ...............

LeBrok
20-12-15, 21:03
Have your say about this question. If a family belonging to population X receives gene flow from a population Y - a single admixture event, i.e. somebody mating with someone belonging to the main population at a certain moment in time - how will component Y dilute in the next generations?
Let's say guy from population Y carries 70% genetic component Y, and his wife 100% genetic component X.
Then their offspring mate with people of population X only. I'd like to know the rate of dilution of component Y through time.
Theoretically the 'foreign" admixture should diminish in a rate of 50% every generation. Granted that any of future spouses don't have any of this "foreign" admixture. If they have some too, the rate of diminishing will only slow down. After about 7 generations it will slip below 1%. In this sub one percent level, weird things will start to happen. The admixture might be transferred as whole thing, or anything other than 50%, or it might disappear completely. I might be wrong, but from what I noticed, is that very small chunks of DNA don't subscribe to 50% law. They might get transferred to next generations or not. More luck than a law.
This is about pure transfer and DNA division during mitoses. Because, actual survival to next generation is a different story. On a single gene level law of natural selection will persevere more than anything, like luck. If some genes in this "foreign" admixture give environmental advantage to survive, it will persist in family for generation and generations, and might spread to entire village or a tribe. Notably the lactose persistent gene has "transferable" advantage, especially in environment of Northern Europe. In areas where people can't count of wheat harvest every year, but there is always, even in cold years, plenty of grass for cows.

LeBrok
20-12-15, 21:06
if there is only mixing of this family of X and Y population, then between the 6th and 8th generation, the "invading" mixture will have disappeared ............... It is more correct to say that after 8th generation admixture may or may not disappear completely.

Mars
21-12-15, 11:59
Very interesting. So the 8th generation would be approximately 200 years after the admixture event, if I'm not wrong... Despite of singular cases (for example, my maternal grandparents were pretty old when my mum got born, so the 25 years rule doesn't work for my case).