In specific (genetic) terms, how do populations diverge?
- secretsauceLv 71 decade agoFavorite Answer
When two populations become genetically isolated (by geography, or any of a number of different ways), they are no longer exchanging genetic material. The allele frequencies for certain mutations begin to acummulate in different ways in the two populations ... new mutations in each population introduce new alleles, and in some cases, new genes entirely.
After enough time, even if if two members of the two populations mate, they will produce offspring with a combination of alleles or genes that are fatal to the offspring, or at the least, will make the offspring infertile. At this point we would say that the two populations are genetically incompatible, and begin referring to them as different *species* (by the definition of "species").
At that point the two populations (now two species) will forever continue to diverge genetically, as any mutations that enters the genome of one population has no way to enter (or affect) the other.
- 1 decade ago
The divergence of populations is actually a number of different aspects of genetics. In essence, a divergence of populations simply means that one group split into multiple, distinct gene pools.
The simplest is produced by a shift in goes like this:
In a population of 500, the recessive trait labelled 'f' is present in only 25% of them.
The group has a sudden environmental or cultural shift that divides them into two seperate, non-interbreeding groups..
The first group has all 125 of the 'f' carriers and 125 of the noncarriers.
The second group has 250 noncarriers.
Over the course of twenty breeding cycles, the groups eventually are reintroduced. Each has bred only within their own population.
Group 1 has, through chance or the trait proving helpful, turned completely into 'f' carriers.
Group 2 possessed no 'f' carriers and remains all noncarriers.
Genetically, the two groups have 'diverged' or split into two distinctly different genetic pools.
Another case is the introduction of specific reproducable mutations in Group 2 that never developed or died out in Group 1. Perhaps a subject in group 2 develops a dominant mutation that allows them to see in low-light settings. If group two is nocturnal or subterranean, this is a beneficial mutation and would most likely be interbred repeatedly, becoming a staple of the group. Again, when compared to each other a number of breeding cycles later, they are now distinctly different.
- 1 decade ago
2- acquistion of DNA ( DNA exchange mechaniams )