Question

ESSAY QUESTION NEED HELP!?!

In guinea pigs, dark hair (D) is dominant over light hair (d) and curly hair (C) is dominant over smooth hair (c). Complete a dihybrid cross for parents with the genotypes: DdCc × DdCc and answer the following in complete sentences. 1. Describe how you would set up a Punnett square for this cross. 2. List the likelihood of each possible offspring genotype. 3. List the likelihood of each possible offspring phenotype.

Answer 1

1) You would first need to set up a 4 by 4 box. For the first genotype, you would distribute the first letter (D) to the third letter (C) to get the allele DC. This allele goes above the first column. Next, you would distribute the first letter again (D) to the last letter (c) to get the allele Dc. This allele goes above the second column. Repeat these 2 steps with the second letter (d) to get the alleles dC (third column) and dc (last column). Since the second genotype is the same, all the alleles on the top columns would follow the rows on the left.

2) 1/16 DDCC, 1/16 DDcc, 1/16 ddCC, 1/16 ddcc, 1/8 DDCc, 1/8 DdCC, 1/8 Ddcc, 1/8 ddCc, 1/4 DdCc

3) 9/16 dark and curly hair, 3/16 dark and smooth hair, 3/16 light and curly hair, 1/16 light and smooth hair