A male and a female are each heterozygous for both cystic fibrosis (CF) and phenylketonuria (PKU). Both conditions are autosomal recessive, and they assort independently.
What proportion of the children will be carriers of one or both conditions?

Organisms with the genotypes AABbCcDd and AaBbCcDd are crossed. What are the expected proportions of the following progeny?

AabbCcDd

Organisms with the genotypes AABbCcDd and AaBbCcDd are crossed. What are the expected proportions of the following progeny?

A–B–C–D–

The wild-type (normal) fruit fly, Drosophila melanogaster, has straight wings and long bristles. Mutant strains have been isolated that have either curled wings or short bristles. The genes representing these two mutant traits are located on separate chromosomes. Carefully examine the data from the following five crosses.

Assign gene symbols and, for each cross, determine the genotypes of the parents.

The wild-type (normal) fruit fly, Drosophila melanogaster, has straight wings and long bristles. Mutant strains have been isolated that have either curled wings or short bristles. The genes representing these two mutant traits are located on separate chromosomes. Carefully examine the data from the following five crosses.

Identify each mutation as either dominant or recessive. In each case, indicate which crosses support your answer.

A male and a female are each heterozygous for both cystic fibrosis (CF) and phenylketonuria (PKU). Both conditions are autosomal recessive, and they assort independently.

What proportion of the children will have either PKU or CF but not both?

A woman expressing a dominant phenotype is heterozygous (Dd) for the gene.

What is the probability that the dominant allele carried by the woman will be inherited by a grandchild?

Three independently assorting genes (A, B, and C) are known to control the following biochemical pathway that provides the basis for flower color in a hypothetical plant:

Three homozygous recessive mutations are also known, each of which interrupts a different one of these steps. Determine the phenotypic results in the F₁ and F₂ generations resulting from the P₁ crosses of true-breeding plants listed here:

colorless (aaBBCC) × green (AABBcc)

Three independently assorting genes (A, B, and C) are known to control the following biochemical pathway that provides the basis for flower color in a hypothetical plant:

Three homozygous recessive mutations are also known, each of which interrupts a different one of these steps. Determine the phenotypic results in the F₁ and F₂ generations resulting from the P₁ crosses of true-breeding plants listed here:

yellow (AAbbCC) × green (AABBcc)