Exam 3: Basic Principles of Heredity

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

In dogs, black coat color (B)is dominant over brown (b), and solid coat color (S)is dominant over white spotted coat (s).A cross between a black, solid female and a black, solid male produces puppies with only black, solid coats.This same female was then mated with a brown, spotted male.Half of the offspring from this cross were black and solid, and half of the offspring were black and spotted.What is the genotype of the female?

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 AB gamete from an AaBb individual?

In poodles, black fur is dominant to white fur.A black poodle is crossed with a white poodle.In a litter of seven, all of the puppies are black.What is the BEST conclusion?

Cystic fibrosis is a human recessive autosomal condition.If two heterozygous parents have two children, what is the probability that they will be born in the order: normal boy and affected girl?

What is the difference between a backcross and a testcross?

Honeybees have a haplo-diploid sex determination system where females develop from a fertilized egg (they are diploid, having one allele from the female queen and one allele from the male), and males develop from unfertilized eggs (they are haploid, having only one allele from the queen).Assuming that the queen is heterozygous for a particular gene, what is the probability that a female will inherit the recessive allele from her mother? What is the probability that a male will inherit a recessive allele from his mother?

Two pea plants with purple flowers are crossed.Among the offspring, 63 have purple flowers, and 17 have white flowers.With a chi-square test, compare the observed numbers with a 3:1 ratio and determine if the difference between observed and expected could be a result of chance.

Which of the following crosses would produce a 3:1 ratio of phenotypes in the next generation?

Round seeds (R)is dominant to wrinkled seeds (r), and yellow seeds (Y)is dominant to green seeds (y).A true-breeding plant with round and yellow seeds is crossed to a true-breeding plant with wrinkled and green seeds.What is the genotype of the F₁ progeny?

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 AaBb zygote from a cross AaBb × AABB?

In dogs, black coat color (B)is dominant over brown (b), and solid coat color (S)is dominant over white spotted coat (s).A cross between a black, solid female and a black, solid male produces puppies with only black, solid coats.This same female was then mated with a brown, spotted male.Half of the offspring from this cross were black and solid, and half of the offspring were black and spotted.Which of the following could be the genotype of the black, solid male?

If an organism of genotype Aa is used for a testcross, what is the genotype of the other individual used in the cross?

In a cross between pure-breeding tall plants with pure-breeding short plants, all of the F₁ are tall.When these plants are allowed to fertilize themselves, the F₂ plants occur in a ratio of 3 tall:1 short.Which of the following is NOT a valid conclusion from these results?

A chi-square test was performed and indicated that the observed numbers of offspring were significantly different from the expected.Which of the following P-values would support this conclusion?

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 wrinkled, green seed in the F₂?

Freckles are caused by a dominant allele.A man has freckles but one of his parents does not have freckles.What is his genotype?

A pedigree shows that two parents are phenotypically normal, but one of their four biological children has a typical autosomal recessive trait.The other three children are phenotypically normal.It is very likely that:

In animals, the inability to make the pigment melanin results in albinism, a recessive condition.Two unaffected parents, who have decided to have three children, have a first child that has albinism (genotype aa).What is the probability that the second and third children will also have albinism?

In Labrador retrievers, black coat color is dominant to brown.Suppose that a black Lab is mated with a brown one, and the offspring are 4 black puppies and 1 brown.What can you conclude about the genotype of the black parent? (Assume that B is the allele for black and b is the allele for brown.)