Final answer:
Inbreeding increases the likelihood of homozygous recessive genetic disorders because closely related individuals are more likely to share deleterious alleles. It leads to inbreeding depression, causing an increase in genetic diseases and abnormalities in offspring.
Step-by-step explanation:
Inbreeding is the mating of closely related individuals, and it is more likely to produce offspring homozygous for a harmful recessive trait because close relatives share many similar alleles, including those that are deleterious when in homozygous form. One of the main consequences of inbreeding is inbreeding depression, which leads to an increase in abnormalities and susceptibility to disease in inbred populations. This occurs because inbreeding can bring together rare, deleterious mutations that lead to harmful phenotypes, which would typically be masked in a genetically diverse population.
As an example, consider a recessive allele that causes a disease. In a diverse population, the chances that two carriers mate is low, and the allele persists at low frequencies without much impact. However, with inbreeding, the chance of two carriers mating increases substantially, leading to a higher occurrence of affected offspring. This is commonly observed in animal breeding where breeders avoid mating close relatives to prevent such genetic issues and maintain the health of their stock.