Question

How does genetic drift affect the frequencies of alleles within a population?

1) Some individuals are more likely to breed with other individuals, and so only their alleles will appear in the next generation.
2) Random mating does not equal uniform mating, as a result of this imperfect sampling some alleles do not get represented in the next generation.
3) In a large population, the likelihood that all individuals will be able to mate is low, so the likelihood that all alleles will be represented in the next generation is also low.
4) Drift results in a variety of genotypes over many generations because the heterozygotes mate randomly leading to some homozygotes of each allele and some heterozygotes, changing the frequency of the alleles.
5) Random mating within a population mixes alleles at a particular locus into many different combinations, and when this happens frequencies of alleles change across generations.

Answer 1

Genetic drift affects allele frequencies in a population through random events that alter the gene pool, especially in small populations. Out of the given options, the one that best describes how genetic drift affects allele frequencies is:

2) Random mating does not equal uniform mating, as a result of this imperfect sampling some alleles do not get represented in the next generation.

Step-by-step explanation:

Genetic drift is a mechanism of evolution in which allele frequencies of a population change over generations due to chance (random sampling of alleles). It is particularly significant in small populations where random events can lead to a large shift in allele frequencies by chance alone.

In a scenario provided, the genetic drift results from a random sample of alleles in an offspring generation that may not represent the entire parental gene pool, leading sometimes to the loss of alleles if individuals die before reproducing. An example is given where a tenth of a population's gene pool is lost due to the premature death of an individual in a small population, dramatically affecting the genetic makeup of the next generation.

Other examples such as bottleneck and founder effect demonstrate how genetic drift can drastically alter allele frequencies due to random events leading to population size reduction or the establishment of new populations by a few individuals.

Out of the given options, the one that best describes how genetic drift affects allele frequencies is:

• Random mating does not equal uniform mating, as a result of this imperfect sampling some alleles do not get represented in the next generation.