6F Punnett Squares

Mice have two unlinked allele pairs that affect fur color. The table shows how allele pairs affect fur color. The term "agouti" describes fur with pigmentation that changes in each hair from the shaft to the tip, giving the fur a banded appearance. Mice with the aa allele pair ware albino, regardless of the second allele-pair combination. What is the probability of albinism in the offspring of a cross between two mice with AaBb alleles?

• 1/16

• 3/16

• 4/16

• 9/16

The inheritance pattern for an autosomal dominant trait is shown in the pedigree. Shaded symbols represent individuals that express the dominant trait. Based on this pedigree, what are the most likely genotypes of individuals I-1 and I-2?

• I-1: aa

  I-2: Aa

• I-1: AA

  I-2: Aa

• I-1: Aa

  I-2: aa

• I-1: aa

  I-2: AA

In humans blood type is determined by the A, B, and O alleles. The A and B alleles are codominant to each other and dominant over the O allele. An individual with the AO genotype and an individual with the BO genotype can produce offspring with which of the following phenotypes?

• O only

• A or B only

• A, B, or O only

• A, B, AB, or O

In cattle the allele for cloven hooves (H) is dominant over the allele for mule-foot hooves (h). The phenotype for each trait is shown in this picture. What is the probability of cloven hooves in the offspring of parents that are heterozygous for the trait?

• 25%

• 50%

• 75%

• 100%

Tags

NGSS.HS-LS3-3

Albinism is an autosomal recessive condition. Which circle graph shows the genotype probability when an albino female mates with a male that is heterozygous for the albinism trait?

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In Holstein cattle the allele for black hair color (B) is dominant over the allele for red hair color (b), and the allele for polled (P), or lacking horns, is dominant over the allele for having horns (p). What is the expected phenotypic ratio of the offspring of a BbPp X BbPp cross if these alleles sort independently?

• 16 black/polled : 0 black/horned : 0 red/polled : 0 red/horned

• 12 black/polled : 0 black/horned : 0 red/polled : 4 red/horned

• 4 black/polled : 4 black/horned : 4 red/polled : 4 red/horned

• 9 black/polled : 3 black/horned : 3 red/polled : 1 red/horned

The four butterflies in the illustrations represent the offspring in the F₁ generation. Which statement is best supported by the phenotypes of these offspring?

• the F₁ generation is composed only of males

• two of the offspring in the F₁ generation will not be able to reproduce

• the F₁ generation is the result of a dihybrid cross

• two of the offspring in the F₁ generation will experience a spontaneous mutation

Chickens can have different types of feathers. Frizzled feathers curl toward a chicken's head. Assume that feather type is determined by a single gene and that the allele for frizzled feathers is dominant over the allele for straight feathers. In a cross between two chickens with straight feathers, what percentage of the offspring can be expected to have frizzled feathers?

• 0%

• 25%

• 50%

• 100%

Facial dimples and free earlobes are both considered dominant human traits. What are the expected phenotypes of the offspring of a female with dimples and free earlobes (DDFf) and a male with no dimples and attached earlobes (ddff)?

• 50% with dimples and free earlobes and 50% with dimples and attached earlobes

• 50% with dimples and free earlobes and 50% with no dimples and attached earlobes

• 75% with dimples and free earlobes and 25% with no dimples and attached earlobes

• 75% with dimples and attached earlobes and 25% with no dimples and free earlobes

Normal fruit flies have brownish-yellow bodies, and this body color is dominant. A mutation in the gene for body color can produce flies with an ebony body color. A homozygous normal fruit fly (e⁺e⁺) is crossed with a homozygous ebony fruit fly (ee). What is the predicted outcome of this genetic cross?

• all the offspring will have ebony bodies

• of the offspring, 75% will have brownish-yellow bodies, and 25% will have ebony bodies

• all the offspring will have brownish-yellow bodies

• of the offspring, 75% will have ebony bodies, and 25% will have brownish-yellow bodies