Define purebred using both terms genotype and allele.

Purebred can be described as organisms that result from true-breeding. True breeding occurs parents who have a homozygous genotype are crossed so that the offspring produced might be similar to them. The alleles of the desired genes will be the same in the parents which will breed and produce similar alleles in their offsprings.

However, the phenomenon of pure breeding limits the gene pool and genetic variety becomes limited by such methods.