Solution: Two closely related species are mated for a few generations, the technique is known as inbreeding, and if this is continued, inbreeding depression occurs. The condition is known as ‘Inbreeding Depression,’ and it causes a reduction of fertility and energy. This occurs because recessive alleles tend to group together and produce harmful effects on offspring. Due to homozygosity, there is an accumulation of recessive genes in the animals and thus results in loss of fertility and vigor.