Two separate populations of the same species can increase genetic variety in a number of ways:
Mutations: random changes in the genetic material that occur in individuals can result in new variations of traits. Over time, these mutations can accumulate in populations, increasing genetic variety.
Gene flow: the exchange of genes between populations, such as through migration or interbreeding, can also increase genetic variety.
Genetic drift: chance events, such as the loss or fixation of certain genes in small populations, can also increase genetic variety over time.
Increased genetic variety can have a number of effects on populations over generations:
Improved adaptation: increased genetic variety can provide a larger pool of genetic variation to draw from, allowing populations to better adapt to changes in their environment.
Reduced susceptibility to diseases: increased genetic variety can reduce the risk of diseases that are specific to certain genotypes, as there is a greater diversity of alleles that can provide resistance.
Increased resilience: populations with increased genetic variety are less likely to experience rapid declines in response to environmental stressors, as they have a greater diversity of traits to draw from.
In general, increased genetic variety is seen as beneficial for populations, as it provides a "genetic safety net" that can help populations persist and adapt over time