Question

aa. Aa. AA. Zebra mussels have the following genotypes and phenotypes. Which cross would produce the greatest number of heterozygous. A) AA x aa. B) Aa x Aa. C) AA x AA. D) as x Aa

Answer 1

In option (A) both of the parent mussels are hom0ygotes, for alleles "a" and "A" respectively. Therefore, every single one (100%) of their offspring would be expected to be Aa heterozygotes. Combinations (B) and (D) yield a lower proportion of heterozygotes (50%), and combination (C) yields none at all. Punnett squares follow:

(A)

| A A

a | aA aA

a | aA aA

(B)

| A a

A | AA Aa

a | aA aa

(C)

| A A

A | AA

| A a

a | aA aa

a | aA aa

Step-by-step explanation:

Answer 2

Answer: A (AA x aa)

Step-by-step explanation:

In option (A) both of the parent mussels are homozygotes, for alleles "a" and "A" respectively. Therefore, every single one (100%) of their offspring would be expected to be Aa heterozygotes. Combinations (B) and (D) yield a lower proportion of heterozygotes (50%), and combination (C) yields none at all. Punnett squares follow:

(A)

| A A

a | aA aA

a | aA aA

(B)

| A a

A | AA Aa

a | aA aa

(C)

| A A

A | AA AA

A | AA AA

(D)

| A a

a | aA aa

a | aA aa