# 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

Feb 9, 2018

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

#### Explanation:

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 below