Gene is heterozygous type B and Molly is homozygous B blood. What are all the possible blood types of their future children? Write it in genotype and phenotype percentages

1 Answer
Feb 9, 2018


All children of Gene and Molly will have B blood group only.


Gene has heterozygous type B blood. The genotype of Gene will be #I^B I^b#.
Molly has homozygous type B blood. The genotype of Molly will be #I^B I^B#.

Gametes contributed by Gene having dominant allele (#I^B#), and recessive allele (b) will be in the ratio of 1:1.

All gametes contributed by Molly will carry dominant allele (#I^B#).

Considering the possible combinations of gametes contributed by the parents to form oospore (zygote), all children will carry one dominant allele (#I^B#).

All the children thus will be phenotypically similar and will have B blood group, because dominant allele can express in phenotype whether in the homozygous or heterozygous state.

However, 50% of children will be homozygous (#I^B I^B#), and 50% will be heterozygous (#I^B I^b#). Thus the ratio of #I^B I^B# (homozygous) and heterozygous (#I^B I^b#) will be in the ratio of 1;1. The genotypic ratio is thus 1:1.

A punnet square for the same is given belowself made