How can we overcome inbreeding depression found in certain high yielding animals?
Animal breeding is practiced for incorporating desirable qualities in animals like better yield and resistance to various pathogens. There are several methods of animal breeding.
Inbreeding involves mating of the superior males and superior females of the same breed having no common ancestors. Inbreeding increases homozygosity and helps in developing pure lines.
But continued inbreeding results in reduced fertility and productivity in animals. This is called inbreeding depression. This can be overcome by crossing these animals with unrelated superior animals of the same breed having no common ancestors. This is called out-crossing. This restores the fertility and yield. Therefore, the best way to overcome inbreeding depression is by out-crossing.
Mating of superior animals of two different breeds is called cross-breeding. This is usually done to combine the desirable qualities of two different breeds.
Mating of animals belonging to two different but related species is called interspecific hybridisation. The hybrids produced are usually sterile.
Hence, option b is correct.