Question

1. There are four alleles for the bald gene that control hair growth in an individual. A bald man who is heterozygous for the first two alleles has children with a non-bald woman who is homozygous for the third allele. All of their children are non-bald.

1. How many gametes will the father produce? Write the allele(s).

2. How many gametes will the mother produce? Write the allele(s).

3. Draw the Punnett Square and the resulting offspring.

4. Draw the relationship between alleles in the space below. Write the allele name in the blank space; dominance is indicated to the left, recessiveness to the right. “>” means the allele on the allele is dominant to the allele; “=” means that you cannot distinguish which allele is dominant or recessive.

______    >    _______   =    ________

A child from the cross above marries a woman who has congenital baldness. She knows that she is homozygous for a rare fourth allele of the baldness gene.

5. Draw a Punnett Square that demonstrate the possible genotypes for their children.

6. All of their resulting children are bald. With this information, draw the relationship between the four alleles of this gene in the space below.

Answer 1

Solution As per the date, there are four alleles for the bald gene that controf hair growth in an Individual. Let's consider them as B,,B2,B3 and B4. Abald man who is heterozygous for the first two alleles can be represented with a genotype B, B₂ The phenotype of B, B₂ is baldness. Women who is homozygous for the third allele (B3B3) is a non balded person parents of B, B, XB3Bzq aneles ① 2 ③ a) 2 Gameles are produced from father with alleles 1 B, and B2 b) Only one gamele is produced from another with 1 allele B a Bi By c) punet square B,B3 Babz All are non hold a) Dua to the presence of so in the centrare all the progeny remained as non-balded male parent contains B, and by showing co donirance So, the relation ship among Bi, By and By is - B3> B = B2 child from above cross marries congenital bald female due to homozygous for the rare fourth allele By By Let's consider & B, B₃X Byby oq gametes . 6 (By)" punnet square : a B B B, B3 progeny is balded. Bald I Band.. + B, and B2 alleles are coding non balded character But B3 and By are coding to balded character. This information combe drawn from the progeny genotypes and phenotypes of above two crosses . Son the relation ship among the alleles is Bu=B3> B, =B2