which of these crosses will only produce heterozygous offspring?

a. aa x aa
b. Aa x Aa
c. AA x Aa
d. Aa x aa
e. AA x aa

Using the Punnett sqaure, which will give you only Aa (heterozygous) offspring?

http://www.google.com/imgres?imgurl=http://upload.wikimedia.org/wikipedia/commons/thumb/1/17/Punnett_square_mendel_flowers.svg/550px-Punnett_square_mendel_flowers.svg.png&imgrefurl=http://commons.wikimedia.org/wiki/Image:Punnett_square_mendel_flowers.svg&h=133&w=133&sz=52&tbnid=wqd9MJU5EaAJ:&tbnh=133&tbnw=133&prev=/images%3Fq%3DPunnett%2Bsquare&sa=X&oi=image_result&resnum=1&ct=image&cd=1

I hope this helps. Thanks for asking.

Oh, the pun possibilities with genetics! Well, my friend, let me clown around and try to make it humorous for you.

The answer you're looking for is b. Aa x Aa. Why? Because "Aa" represents a heterozygous genotype with two different alleles, one dominant and one recessive. When you cross two heterozygotes, there is a 25% chance of homozygous dominant offspring (AA), a 25% chance of homozygous recessive offspring (aa), and a 50% chance of heterozygous offspring (Aa). So, no matter what, you'll always get some funny business in the form of heterozygous offspring!

The cross that will only produce heterozygous offspring is:

b. Aa x Aa

In this cross, both parents carry one dominant allele (A) and one recessive allele (a). The offspring will inherit either the dominant allele or the recessive allele from each parent, resulting in heterozygous genotype (Aa) for all the offspring.

To determine which cross will only produce heterozygous offspring, we need to consider the genotypes of the parents involved in each cross.

Aa represents a heterozygous genotype, where 'A' and 'a' represent different alleles of a specific gene. On the other hand, AA represents a homozygous dominant genotype, where both alleles are the same dominant allele. Similarly, aa represents a homozygous recessive genotype, where both alleles are the same recessive allele.

Let's analyze each of the given crosses:

a. aa x aa: This cross involves two homozygous recessive parents. Since both parents have the same recessive allele (aa), the offspring will also have a homozygous recessive genotype (aa). So, this cross will only produce homozygous offspring, not heterozygous.

b. Aa x Aa: This cross involves two heterozygous parents. Each parent carries one dominant allele (A) and one recessive allele (a). When these parents are crossed, they can produce offspring with both homozygous (AA and aa) and heterozygous (Aa) genotypes. So, this cross will produce both homozygous and heterozygous offspring, not only heterozygous.

c. AA x Aa: This cross involves a homozygous dominant parent (AA) and a heterozygous parent (Aa). When these parents are crossed, they can produce offspring with both homozygous dominant (AA) and heterozygous (Aa) genotypes. So, this cross will produce both homozygous dominant and heterozygous offspring, not only heterozygous.

d. Aa x aa: This cross involves a heterozygous parent (Aa) and a homozygous recessive parent (aa). When these parents are crossed, they can only produce offspring with a heterozygous genotype (Aa). So, this cross will only produce heterozygous offspring.

e. AA x aa: This cross involves a homozygous dominant parent (AA) and a homozygous recessive parent (aa). When these parents are crossed, they can only produce offspring with a heterozygous genotype (Aa). So, this cross will only produce heterozygous offspring.

Therefore, the crosses that will only produce heterozygous offspring are:

d. Aa x aa
e. AA x aa