Exam 3: Basic Principles of Heredity

While doing field work in Madagascar, you discover a new dragonfly species that has either red (R)or clear (r)wings.Initial crosses indicate that R is dominant to r.You perform three crosses using three different sets of red-winged parents with unknown genotype and observe the following data: Which cross is likely to have at least one parent with the genotype RR?

Round seeds (R)is dominant to wrinkled seeds (r), and yellow seeds (Y)is dominant to green seeds (y).A true-breeding pea plant with round and yellow seeds is crossed to a true-breeding plant with wrinkled and green seeds.The F₁ progeny are allowed to self-fertilize.What is the probability of obtaining a round, yellow seed in the F₂?

Which of the following crosses would produce a 1:1 ratio of phenotypes in the next generation?

A man has either an AaBB or AABb genotype with equal probability.Assume these genes assort independently.What is the probability of the man producing an AB gamete?

In a cross between AABbCcDD and AaBbccdd, what proportion of the offspring would be expected to be A_B_C_D_? (A_ means AA or Aa.)

Freckles are caused by a dominant allele.A man has freckles but one of his parents does not have freckles.The man has fathered a child with a woman that does not have freckles.What is the probability that their child has freckles?

A pedigree for a particular autosomal recessive human trait is shown below: What is the probability that if III-3 and III-4 marry, their first child will be affected with this trait?

Two gene loci, A and B, assort independently, and alleles A and B are dominant over alleles a and b.What is the probability of producing an A_B_ phenotype from a cross aabb × AABB?

Two gene loci, A and B, assort independently, and alleles A and B are dominant over alleles a and b.What is the probability of producing an A_B_ phenotype from a cross AaBb × AaBb?

Round seeds (R)is dominant to wrinkled seeds (r), and yellow seeds (Y)is dominant to green seeds (y).A true-breeding pea plant with round and yellow seeds is crossed to a true-breeding plant with wrinkled and green seeds.The F₁ progeny are allowed to self-fertilize.What is the probability of obtaining a yellow seed in the F₂?

In peas, tall (T)is dominant to short (t).A homozygous tall plant is crossed with a short plant.The F₁ are self-fertilized to produce the F₂.Both tall and short plants appear in the F₂.If the short F₂ are self-fertilized, what types of offspring and proportions will be produced?

In sesame, the one-pod condition (P)is dominant to three-pod (p), and normal leaf (W)is dominant to wrinkled (w).These characteristics assort independently.A one-pod, wrinkled leaf × one-pod, normal leaf cross gave a progeny of 654 one-pod, normal leaf plants and 224 three-pod, normal leaf plants.What are the likely genotypes of the parents in this cross?

A couple has six daughters and is expecting a seventh child.What is the probability that this child will be a boy?

Which of the following was NOT one of Mendel's conclusions based on his monohybrid crosses?

The ability to roll the tongue is caused by a dominant allele.A woman is a "roller, " but one of her parents is not.The woman is expecting a child with a man who is a "nonroller." What is the probability that their first child will be a "roller"?

A man has either an AaBB or AABb genotype with equal probability.Assume these genes assort independently.What is the overall probability that the man will produce an Ab gamete?

The pedigree below shows the segregation of an autosomal recessive trait in humans.Unless there is evidence to the contrary, assume that individuals who marry into the family do not carry the recessive allele.If IV-1 and IV-2 marry, what is the probability that their first child will have this trait?

In deer mice, red eyes (r)is recessive to normal black eyes (R).Two mice with black eyes are crossed.They produce two offspring, one with red eyes and one with black eyes.Give the genotypes of parents and offspring of this cross.

Which of the following is NOT a typical characteristic of human traits that follow an autosomal recessive inheritance pattern?

For a particular plant, red flowers (A)are dominant over yellow flowers (a).An initial cross was made between a plant that was ttrue-breeding for red flowers, and another plant ttrue-breeding for yellow flowers.F₁ progeny, all having red flowers, were allowed to form seeds, which were then planted to generate F₂ progeny.Pollen from all the resulting F₂ plants was pooled and used to fertilize ttrue-breeding yellow plants.What proportion of the progeny resulting from this cross would be expected to have yellow flowers?