Michigan Test for Teacher Certification (MTTC) Secondary Integrated Science Practice test

Which factors can increase genetic variation in a population?

1. Natural selection and emigration

2. Mutations and large population size

3. Random mating and small population size

4. Isolation and limited reproduction

The correct answer is: Mutations and large population size

Genetic variation within a population is essential for evolution and adaptability. The correct answer emphasizes the role of mutations and large population size in increasing genetic variation. Mutations are changes in the DNA sequence that can introduce new alleles into a population. These alterations can occur due to various factors, such as environmental influences or errors during DNA replication. When mutations happen in reproductive cells, they can be passed on to the next generation, thereby contributing to the overall genetic diversity. A large population size plays a crucial role in preserving genetic variation. In smaller populations, genetic drift can have a significant effect, potentially leading to the loss of alleles over generations. However, a larger population size tends to maintain more genetic variation because there is a higher likelihood of different alleles being represented as well as more opportunities for mutations to arise and persist within the population. The other options reflect concepts that may not effectively contribute to increasing genetic variation. For example, natural selection favors certain traits over others, which may reduce variation. Small population size is likely to diminish genetic variation due to the effects of genetic drift. Random mating does promote genetic diversity, but in combination with a small population size, it may not significantly help in increasing genetic variation. Isolation can lead to decreased genetic variation by limiting