Question

Which two genotypes in an individual would be expressed as the same phenotype in a diploid organism?

A) homozygous dominant and heterozygous
B) homozygous recessive and heterozygous
C) homozygous dominant and homozygous recessive

Answer 1

In a diploid organism, homozygous dominant (AA) and heterozygous (Aa) genotypes are expressed as the same phenotype due to the presence of at least one dominant allele, which masks the recessive allele in heterozygous individuals.

Step-by-step explanation:

The question concerns the expression of genotypes as phenotypes in a diploid organism. Specifically, the two genotypes that would result in the same phenotype are the homozygous dominant (AA) and the heterozygous (Aa) configurations. This occurs because in genetics, especially when considering Mendelian inheritance, the dominant allele will mask the presence of the recessive allele in the phenotype, resulting in organisms with these two different genotypes appearing identical in their physical characteristics.In a diploid organism, homozygous dominant individuals carry two copies of the dominant allele for a given trait, while heterozygous individuals carry one dominant and one recessive allele.

However, because the dominant allele is expressed over the recessive allele, both of these genotypes will exhibit the same phenotype - that of the dominant trait. On the other hand, the phenotype associated with the recessive trait will only appear in individuals that are homozygous recessive (aa), as they lack the dominant allele altogether.