Zebra mussels are originally native to Russia. In the mid-1980s, zebra mussels were introduced into the Great Lakes region of the United States where they rapidly reproduced. Females can produce up to one million eggs per year. In one zebra mussel population, most of the individuals have dark, zebra-striped shells (genotype AA). However, solid light-colored shells (genotype aa) occur in 1 of every 10,000 individuals. The solid light-colored shells indicate mussels that are not hardy in cold water temperatures (

Question

Zebra mussels are originally native to Russia. In the mid-1980s, zebra mussels were introduced into the Great Lakes region of the United States where they rapidly reproduced. Females can produce up to one million eggs per year. In one zebra mussel population, most of the individuals have dark, zebra-striped shells (genotype AA). However, solid light-colored shells (genotype aa) occur in 1 of every 10,000 individuals. The solid light-colored shells indicate mussels that are not hardy in cold water temperatures (<
C). Heterozygous individuals (Aa) have solid, dark-colored shells.
Question 1
If you cross a mussel with dark, zebra-striped shells with a mussel with solid light-colored shells, how many offspring would you expect to have the have solid, dark-colored shells?
Responses
A	0%0%
B	50%50%
C	75%75%
D	100%100%
Question 2
Which cross would produce the greatest genetic diversity among the offspring?
Responses
A	AA x aaAA x aa
B	AA x AaAA x Aa
C	aa x Aaaa x Aa
D	Aa x Aa

GPT-4o mini · Answer

To answer the questions, we need to analyze the genetic crosses provided.

Question 1: If you cross a mussel with dark, zebra-striped shells (genotype AA) with a mussel with solid light-colored shells (genotype aa), we can set up the Punnett square:

Parent 1 (AA) can only produce gametes with A.
Parent 2 (aa) can only produce gametes with a.

The possible offspring genotypes are:

All offspring will be Aa (100% heterozygous), which have solid, dark-colored shells.

Thus, the answer is D: 100%.

Question 2: We want to determine which cross will produce the greatest genetic diversity among the offspring. Let's analyze each cross:

A. AA x aa

All offspring will be Aa (0 genetic diversity, all are the same).

B. AA x Aa

Offspring: 50% AA and 50% Aa (some diversity, but only 2 genotypes).

C. aa x Aa

Offspring: 50% Aa and 50% aa (some diversity, producing 2 different genotypes).

D. Aa x Aa

This cross produces: 25% AA, 50% Aa, and 25% aa (3 different genotypes).

Among these options, D: Aa x Aa produces the greatest genetic diversity because it results in three different genotypes among the offspring.

So, the answer is D: Aa x Aa.