Question

In cows, long hair is dominant to short hair. in a cow that is heterozygous for long hair, what percentage of the cells undergoing meiosis will carry the dominant allele?

Answer 1

Given –

Organism under consideration - cow

Character – size of the hair

Dominant trait – long hair

Recessive trait – short hair

Genotype – heterozygous dominant

Solution –  

Let the dominant trait be represented by L

Let the recessive trait be represented by l

In heterozygous condition the parent cow will have alleles as – Ll (male), Ll (female)

Cross between male and female would result in  

   

L l

L LL Ll

l Ll ll

Phenotype of the offspring – 75% with long hair, 25% with short hair

Genotype of the offspring – Homozygous dominant – 25%

                                               Heterozygous dominant – 50%

                                               Recessive dominant – 25%

Therefore, offspring's with dominant allele is 75% (25+ 50)