How does inbreeding affect genetic variation?

Inbreeding reduces genetic variation by increasing the likelihood of homozygous genotypes in a population.

Inbreeding is the mating of closely related individuals, which can lead to a decrease in genetic variation. This is because close relatives share a higher proportion of their genes compared to unrelated individuals. When these relatives mate, their offspring are more likely to inherit the same alleles from both parents, leading to homozygosity. This means that the offspring have two copies of the same allele for a particular gene.

The increase in homozygosity reduces the genetic diversity within a population. Genetic diversity is crucial for the survival and adaptation of a species. It provides the raw material for natural selection to act upon and allows populations to adapt to changing environments. When genetic diversity is reduced, a population may not have the necessary genetic variation to adapt to new conditions or resist diseases.

Inbreeding can also lead to the expression of harmful recessive traits. These traits are usually masked in a heterozygous individual, but can become apparent in a homozygous individual. This can lead to a decrease in the overall fitness of a population, a phenomenon known as inbreeding depression.

Furthermore, inbreeding can lead to a reduction in the effective population size. This is because not all individuals in an inbred population contribute equally to the next generation. Some individuals may have many offspring, while others may have none. This can further reduce genetic variation and increase the risk of extinction.

In conclusion, inbreeding can have a significant impact on genetic variation. It increases homozygosity, reduces genetic diversity, can lead to the expression of harmful recessive traits, and can reduce the effective population size.