Final answer:
Inbreeding depression and genetic drift can occur together in small, isolated populations or after bottleneck events that drastically reduce population size, leading to a decline in genetic diversity and an increase in the expression of deleterious alleles.
Step-by-step explanation:
Inbreeding depression and genetic drift can work at the same time under certain conditions, such as in small isolated populations or after a drastic reduction in population size due to a bottleneck event. Inbreeding depression is the reduced biological fitness in a population due to mating of closely related individuals which can result in an increase in abnormalities and diseases. This often occurs when a population's size becomes very small, exacerbating the reductions in individual fitness due to the increased probability of deleterious alleles being expressed.
Genetic drift is the change in the frequency of an allele in a population due to random sampling of organisms. It can be magnified by events such as natural disasters, which can randomly kill a large portion of the population, leading to a bottleneck effect. This could result in a drastic reduction in genetic diversity and alter the genetic structure of a population significantly. When these two phenomena occur simultaneously, the effects on population genetic structure can be profound, potentially leading to an accelerated risk of extinction.