two populations that have no gene flow between them are likely to have developed genetic differences.
two populations that have no gene flow between them are likely to?
have developed genetic differences
when gene flow is blocked by physical barriers, this results in allopatric speciation or a geographical isolation that does not allow populations of the same species to exchange genetic material. physical barriers to gene flow are usually, but not always, natural. they may include impassable mountain ranges, oceans, or vast deserts. in some cases, they can be artificial, man-made barriers, such as the great wall of china, which has hindered the gene flow of native plant populations. one of these native plants, "ulmus pumila", demonstrated a lower prevalence of genetic differentiation than the plants "vitex negundo," "ziziphus jujuba," "heteropappus hispidus," and "prunus armeniaca" whose habitat is located on the opposite side of the great wall of china where "ulmus pumila" grows. this is because "ulmus pumila" has wind-pollination as its primary means of propagation and the latter-plants carry out pollination through insects. samples of the same species which grow on either side have been shown to have developed genetic differences, because there is little to no gene flow to provide recombination of the gene pools.
gene flow
in population genetics, gene flow (also known as gene migration or allele flow) is the transfer of genetic variation from one population to another. if the rate of gene flow is high enough, then two populations are considered to have equivalent allele frequencies and therefore effectively be a single population. it has been shown that it takes only "one migrant per generation" to prevent populations from diverging due to drift. gene flow is an important mechanism for transferring genetic diversity among populations. migrants change the distribution of genetic diversity within the populations, by modifying the allele frequencies (the proportion of members carrying a particular variant of a gene). high rates of gene flow can reduce the genetic differentiation between the two groups, increasing homogeneity. for this reason, gene flow has been thought to constrain speciation by combining the gene pools of the groups, thus preventing the development of differences in genetic variation that would have led to full speciation. in some cases migration may also result in the addition of novel genetic variants to the gene pool of a species or population.
gene flow