PATHOLOGY

Detailed explanation-1: -The ability to roll tongue is dominant over inability to do it. If the dominant allele is R and the recessive allele is r, therefore the two individuals have the homozygous recessive character. This means the genotype of the organism will be ‘rr’.

Detailed explanation-2: -and observed that 67.1% of females and 62.9% of males could roll their tongues, and the remaining could not do it. A 1980 study with 992 people also found similar percentages, in 66.84% of females and 63.7% of males possessing the ability.

Detailed explanation-3: -A person with the Rr genotype for tongue rolling would be able to roll his or her tongue, because he or she has the dominant allele that allows tongue rolling. So “tongue rolling” is his or her phenotype.

Detailed explanation-4: -The correct answer is option D. The father is homozygous dominant (TT), while the mother is heterozygous (Tt). Following the law of Dominance, both parents, having the dominant gene, would express the dominant trait and be tongue-rollers. The possible genotypes of their offspring are TT and Tt with a ratio of 1:1.