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) Firstly, lets sort out the alleles for the dominant and recessive characteristics. The dominant brown allele will be written as B and the recessive red hair allele will be written as b.

2) Lets sort out the genotype of the parents. The parent having homozygous brown coloured hair will carry the alleles BB. The parent carrying the heterozygous brown coloured hair will carry the alleles Bb.

3) The punnet square from these parents will be drawn as follows:

      B        b

B    BB     Bb

B    BB     Bb

4) Now, lets predict the phenotype of the offsprings. The results from the punnet square show that all of the offsprings will have brown coloured hair.

5) The genotype for the children will have 50% chance to be homozygous brown (BB) and 50% chance to be heterozygous brown (Bb).