Inbreeding can reduce the fitness of a population in the short term due to an increase in what?

Inbreeding can lead to a reduction in the overall fitness of a population primarily due to an increase in the incidence of deleterious recessive traits. When individuals that are closely related breed, there is a higher likelihood that they will share alleles that are similar, including alleles that may be harmful or carry genetic diseases.

In a diverse population, harmful recessive traits are often masked by dominant alleles, which can prevent their expression. However, in an inbred population, the chance of two copies of a deleterious recessive allele pairing up in an offspring increases significantly. This results in a greater prevalence of these negative traits, which can decrease survival and reproduction rates in the population.

This phenomenon underscores the importance of genetic diversity in maintaining the health and viability of species, as it helps ensure that harmful genotypes are less likely to become prevalent.