The cleft chin trait follows a dominant-recessive inheritance pattern with cleft chin being the dormant trait.John is heterozygous for a cleft chin as is his wife Betty.John and Betty have three kids all of which have a cleft chins.According to Punnett square prediction what is the likely hood that their next child will have a cleft chin?
A) 25% chance the same probability for all subsequent children
B) 0% because the three pervious children have cleft chins already
C) 100% chance because the mother and father both have cleft chins
D) 75% chance the same probability for all subsequent children

Question

Quizplus · Accepted Answer

Since John is heterozygous for a cleft chin, his genotype can be represented as Cc. Similarly, Betty's genotype can also be represented as Cc since she is heterozygous. When their genotypes are crossed on a Punnett square, the resulting offspring have a 75% chance of inheriting at least one copy of the dominant allele for the cleft chin trait. This means that the probability of the next child having a cleft chin is also 75%. The previous children having cleft chins does not affect the probability of the next child having a cleft chin since the inheritance pattern follows the laws of probability, and each child is an independent event. Therefore option D is the best choice.

The Cleft Chin Trait Follows a Dominant-Recessive Inheritance Pattern with Cleft