LIFE SCIENCE

Detailed explanation-1: -Only individuals with an aa genotype will express a recessive trait; therefore, offspring must receive one recessive allele from each parent to exhibit a recessive trait. One example of a recessive inherited trait is a smooth chin, as opposed to a dominant cleft chin.

Detailed explanation-2: -In this case “a” is the mutated allele of the gene and “A” is non-mutated. Individual who receives mutated allele from both parents (aa) would be affected with disease. Another persons “AA” and “Aa” do not show phenotypes of disease.

Detailed explanation-3: -The term “homozygous” is used to describe the pairs “AA” and “aa” because the alleles in the pair are the same, i.e. both dominant or both recessive. In contrast, the term “heterozygous” is used to describe the allelic pair, “Aa”.

Detailed explanation-4: -Dominant refers to the relationship between two versions of a gene. Individuals receive two versions of each gene, known as alleles, from each parent. If the alleles of a gene are different, one allele will be expressed; it is the dominant gene.