Question

1. How would a scientist would recognize genetic drift, from a current population. Explain.

2. What factors would prevent genetic drift, and explain why (Good description of factors)

Answer 1

The allelic frequency generally changed in a population due to natural selection and their reproductive success. Sometimes, the population would evolve by random chances, which is termed as genetic drift. The changes in allelic frequencies in a population may change by random selection of one allele than the other by the parental generation to transmit them to offspring so that eventually by several generations the allelic proportions may change over time. The genetic drift in a population can be estimated by the evaluating the differences in the number of individuals possessing specific genotypes in one generation to the other.

There are so many factors causing changes in allelic frequencies by sampling errors. the major factors include-

Population size: Even though it is a random change, genetic drift is more favoured due to small population size, than the large populations. In small population sampling errors are more frequent than the large populations. over generations, if the differences are fixed, slowly the frequency of allele may change.

The rare genotypes may be selected or completely eliminated in one random sampling (in a generation) in the small population and during next generations, the frequency of that genotype completely changed. larger populations favour all genotypes to transfer to the next generation so the elimination or fixing of rare genotypes is not as frequent as in small populations.

Effective population size: The number of individuals in a population contribute to the next generation (number of fertile individuals) is also affect the random changes in allele frequencies. If the extreme genotypes are expressed by infertile individuals than they will not be transferred to the next generation, results in changes in allele frequencies.

Inbreeding: Inbreeding decrease the chance of genetic variations but it biases the transferring alleles from one generation to the others and slowly changes the allelic frequency.