Inbreeding

Inbreeding can be a result of incest, assortative mating, small population size, or population sub-structuring. This leads to the increase of the homozygous population and the deficiency of heterozygous. By exposing the recessive homozygous trait, before hidden by heterozygosity with dominant alleles relative of random mating, inbreeding can lead to different benefits and costs to a population. 

One of the benefits is the increase in genetic transmission. The costs are many, including inbreeding depression, in which deleterious recessive alleles emerge in homozygotes form. It also leads to reduced fitness when heterozygotes are more fit than both homozygotes (as we observed on the R exercise). Moreover, it can reduce genetic variation among families or populations, and increase selection by exposing deleterious recessive mutations. Small and isolated populations are prone to inbreeding and suffering from inbreeding depression, being a central concept of conservation biology as well.

Reference:

Inbreeding and inbreeding depression. (n.d.). Retrieved March 05, 2021, from https://www.oxfordbibliographies.com/view/document/obo-9780199941728/obo-9780199941728-0124.xml