Question

Do genetic drift and gene flow consistently increase the frequency of alleles that enhance survival and reproduction? Explain.

Answer 1

Answer) Genetic drift is a process in which allele frequencies within a population change by chance alone as a result of sampling error from generation to generation. Genetic drift is a random process that can lead to large changes in populations over a short period of time. Genetic drift can be caused by a number of chance phenomena, such as differential number of offspring left by different members of a population so that certain genes increase or decrease in number over generations independent of selection, sudden immigration or emigration of individuals in a population changing gene .Genetic drift occurs in all populations of non-infinite size, but its effects are strongest in small populations.Genetic drift may result in the loss of some alleles (including beneficial ones) and the fixation, or rise to 100 percent frequency, of other alleles. Genetic drift, unlike natural selection, does not take into account an allele’s benefit (or harm) to the individual that carries it. That is, a beneficial allele may be lost, or a slightly harmful allele may become fixed, purely by chance.
A beneficial or harmful allele would be subject to selection as well as drift, but strong drift (for example, in a very small population) might still cause fixation of a harmful allele or loss of a beneficial one.