Copy of Unit 6 Re-Test - Genetics (5/2/2026)

In mice, black fur is dominant to white fur. White fur appears only in mice that are homozygous recessive for the trait. If fur color is controlled by a single gene, what is the expected outcome of crossing two mice that are heterozygous for black fur?

In rabbits, upright ears are dominant to floppy ears.

What are the expected genotypes of the offspring if a homozygous upright-eared rabbit mates with a floppy-eared rabbit?

Some bird colors are determined by codominance. Possible genotypes and phenotypes of birds are shown below.

Which table shows the expected phenotypes of offspring resulting from a cross between a blue bird and a white bird?

#16 on Test

In a population of snapdragon plants, some individuals have red flowers, some have pink flowers, and some have white flowers. One gene controls flower color and has two alleles. The allele for red flowers (F^R) is incompletely dominant over the allele for white flowers (F^W), so heterozygous plants have pink flowers.

Which cross below has the highest probability of producing pink-flowered offspring?

#23 on Test

Color blindness is an X-linked recessive trait that affects a person’s ability to distinguish certain colors. Because the gene is located on the X chromosome, mothers can pass this trait to their sons. A woman who is color-blind marries a man with normal vision.

The couple have a daughter. What are the chances she is a carrier for the disorder?

Extra Sex Linked Question

Hemophilia is an X-linked recessive disorder that affects the blood’s ability to clot properly. Because the gene is located on the X chromosome, mothers can pass the disorder to their sons. A woman who is a carrier for hemophilia marries a man who does not have hemophilia.

What is the probability that they will have a son with hemophilia?

#13 on Test

What blood types are possible for the children of a woman who is heterozygous for type A and a man who is homozygous for blood type B?

#19 on Test

In guinea pigs, the allele for rough fur (R) is dominant over smooth fur (r), and the allele for dark eyes (D) is dominant over light eyes (d).

What is the expected phenotypic ratio of the offspring from a RrDd × RrDd cross if these alleles assort independently?

#21 on Test - Made it into multiple selection

Dimples and the ability to roll the tongue are inherited traits. Dimples (D) are always dominant to no dimples (d). The ability to roll the tongue (R) is always dominant to not being able to roll the tongue (r). The alleles for no dimples and not being able to roll the tongue are recessive.

If both parents are heterozygous for both traits, what would be the genotype of an offspring with no dimples and the ability to roll the tongue?

#15 on Test

A model of the genetic control of coat color in Guinea pigs is shown.

Which Punnett square represent a cross that would produce a white offspring?