Genetic Variation: Processes Impacting Allele Frequencies
Genetic variation refers to the diversity of alleles within a population. Several evolutionary processes influence this variation. Let's examine the impact of each option:
Mutation's Role in Variation
Mutation introduces new genetic material (alleles) into a population. This is the ultimate source of new genetic variation.
Migration's Effect on Variation
Migration, also known as gene flow, occurs when individuals move between populations. This process can introduce new alleles into a recipient population or alter allele frequencies, generally increasing genetic variation.
Recombination's Contribution
Recombination, occurring during meiosis, shuffles existing alleles into new combinations on chromosomes. This creates new genotypes and thus increases genetic variation within the population.
Genetic Drift's Impact on Variation
Genetic drift involves random fluctuations in allele frequencies from one generation to the next, particularly significant in small populations. By chance, some alleles may become more or less common, and alleles can even be lost entirely. Therefore, genetic drift typically leads to a decrease in genetic variation within a population.
Conclusion on Genetic Variation
Among the given options, genetic drift is the process that does NOT typically contribute to an increase in genetic variation; instead, it tends to reduce it.
Important Questions from Genetic drift
- Which one of the following statements about genetic drift is accurate?
- A few years ago, a very small population of zebrafish became isolated by a newly built dam. As a result, which statement is most likely to be true about this population of zebrafish now?
- Which two of the following processes can result in a decline in heterozygosity in populations?
I) inbreeding; II) genetic drift; III) mutation; IV) random mating In a population of birds on an island, the average beak size reduced over one generation. A researcher estimated the association between beak size and relative fitness, shown in the graph. The estimated slope was –0.05 with a 95% confidence interval of -0.15 to 0.09.
Which one of the following evolutionary processes acting on beak size is the most likely reason for the observed reduction in beak size?
- Two isolated populations X and Y have 100 and 10000 individuals, respectively. Both populations have the same starting allele frequencies of p=0.5 and q=0.5. After 1000 generations of genetic drift, which of the following statements is true about the heterozygosity at this locus in these two populations?
