Question

Brown hair is dominant over red hair. What will the genotypes and phenotypes of the offspring of a cross between a homozygous brown hair person and a heterozygous brown hair person?
Do the process in five steps.

1.

2.

3.

4.

5.

Answer 1

Answer:

1) In the first step, we need to predict the possible alleles for the cross. The dominant allele will be written with a capital letter. The recessive allele will be written with a small letter. Hence, the allele for brown hair colour will be B and the allele for red hair colour will be b.

2) In the second step, we need to determine the genotype of the parents. The genotype of the homozygous dominant parent will be BB. The genotype of the heterozygous brown hair colour will be Bb.

3) The punnet square for cross between these parents can be shown as follows:

        B           b

B     BB       Bb

B     BB       Bb

4) In the fourth step, lets determine the phenotype of the children. The phenotype of all the offsprings born will be brown hair colour.

5) The genotype from the punnet square shows that there is a 50% chance that the offsprings will be heterozygous dominant (Bb) for brown hair colour and their will be a 50% chance that the child born will be homozygous dominant (BB).