Answer to Question #143839 in Genetics for victory

Question

Achondroplasia and syndactyly are autosome dominant disorders in a human. In a family, where father had achondroplasia and normal structure of hand; mother had syndactyly and without achondroplasia, there were born a healthy daughter. Determine the probability of birth of the next healthy child.

Answer 1

A-achondroplasia

a-normal structure of the skeleton

B-syndactyly

b- normal structure of hand

A_bb- father had achondroplasia and normal structure 

aaB_-mother had syndactyly and without achondroplasia

aabb-healthy daughter

If the daughter is healthy, her genotype is aabb, therefore the genotype of the father is Aabb, and the mother is aaBb, because the daughter receives one gene from the allelic pairs from the mother's organism, and the other from the father's.

P: ♂ Aabb x ♀aaBb

F1 AaBb -1/4= 25%-children with achondroplasia and syndactyly;

Aabb- 1/4= 25%-children with achondroplasia and normal structure of hand;

 aaBb- 1/4= 25%- children with normal structure of the skeleton and syndactyly;

aabb - 1/4= 25%-healthy kids.

   The probability of birth of the next healthy child constitute 25%.