BackIn the rats identified in Problem 10, a third independently assorting gene involved in determination of coat color is the C gene. At this locus, the genotype C– permits expression of pigment from genes B and D. The cc genotype, however, prevents expression of coat color and results in albino rats. For each of the following crosses, determine the expected phenotype ratio of progeny.
BbDdCC×BbDdCC
In the rats identified in Problem 10, a third independently assorting gene involved in determination of coat color is the C gene. At this locus, the genotype C– permits expression of pigment from genes B and D. The cc genotype, however, prevents expression of coat color and results in albino rats. For each of the following crosses, determine the expected phenotype ratio of progeny.
BbDDCc×BbDdCc
In the rats identified in Problem 10, a third independently assorting gene involved in determination of coat color is the C gene. At this locus, the genotype C– permits expression of pigment from genes B and D. The cc genotype, however, prevents expression of coat color and results in albino rats. For each of the following crosses, determine the expected phenotype ratio of progeny.
BBDdcc×BbddCc
Strains of petunias come in four pure-breeding colors: white, blue, red, and purple. White petunias are produced when plants synthesize no flower pigment. Blue petunias and red petunias are produced when plants synthesize blue or red pigment only. Purple petunias are produced in plants that synthesize both red and blue pigment (the mixture of red and blue makes purple). Flower-color pigments are synthesized by gene action in two separate pigment-producing biochemical pathways. Pathway I contains gene A that produces an enzyme to catalyze conversion of a colorless pigment designated to blue pigment. In Pathway II, the enzymatic product of gene B converts the colorless pigment designated to red pigment. The two genes assort independently.
True-breeding red petunias are crossed to pure-breeding blue petunias, and all the F₁ progeny have purple flowers. If the F₁ are allowed to self-fertilize and produce the F₂, what is the expected phenotypic distribution of the F₂ progeny? Show your work.
List all the different gametes that are possible from the following genotypes.
AabbCCdd
List all the different gametes that are possible from the following genotypes.
AaBbCcDd
List all the different gametes that are possible from the following genotypes.
AabbCcDD
List all the different gametes that are possible from the following genotypes.
AABbCcDd
Organisms with the genotypes AABbCcDd and AaBbCcDd are crossed. What are the expected proportions of the following progeny?
A–B–ccdd
Organisms with the genotypes AABbCcDd and AaBbCcDd are crossed. What are the expected proportions of the following progeny?
a phenotype identical to either parent
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–
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?