The question is incomplete here is the complete question " After a rare fur color mutation occurred, a mice population evolved to have this new coat coloration (i.e. over many generations more individuals in the population had this new color variant). Explain how genetic drift could lead to this increase in frequency of individuals in the population with this new color variant over many generations. Also explain why natural selection is likely to have a greater effect and what conditions make it more likely that natural selection will have such an effect"
Answer:
Genetic drift is an evolutionary process or mechanism where the allele frequency in a population varies over generation due to sampling errors. This happens more in the smaller population and contributes to the absence of a specific gene which over time has established a genotypical or phenotypic character. In genetic drift, the alleles that never occur are likely to be lost forever, and the cycle continues until the allele is lost or there is only one allele that affects the characteristics of the whole. Genetic drift will lead to an rise in individuals with a new color variant for several generations because it is slowly leading to sampling error and change in the frequency of the allele, and will continue to do so until the older allele is removed. The loss of the allele due to a random shift in frequency with each generation contributes to new color fur generating population.
Natural selection is a mechanism in which variations in the allele frequency do not change automatically but by adjusting according to the changing conditions. It is the main difference as compared to genetic drift where shifts arise randomly in the frequency of the alleles. Natural selection is a mechanism in which only the superior genes are able to survive by adapting to the environment and destroying the weaker ones. This leads to incremental shifts of altered phenotypic and genotypical characteristics. Natural selection is likely to have more effect because it removes the unused allele or genes and prefers those genes that adapt readily and, in this case, the natural selection prefers the unusual fur color mutation.