Exam 4: The Chromosome Theory of Inheritance

Which of the following statements is FALSE?

Structures that appear along the synaptonemal complex during pachytene where genetic material is exchanged between nonsister chromatids are the ________.

The stage of mitosis when sister chromatids separate from each other and migrate to opposite poles of a cell is called

Hemophilia is caused by an X-linked recessive mutation in humans.If a woman whose paternal uncle (father's brother)was a hemophiliac marries a man whose brother is also a hemophiliac, what is the probability that their first child will have hemophilia? (Assume that no other cases of hemophilia and no hidden carriers exist in the pedigree. )

Individuals with an XXY karyotype are ________ in humans and ________ in fruit flies.

In Drosophila virilis, somatic cell nuclei contain 12 chromosomes while sperm nuclei contain only 6 chromosomes.What does n equal for this species?

Normal fruit flies have red eyes.Flies with mutations that block the function of the X-linked white gene have white eyes.The wild-type allele is completely dominant to mutant alleles.A white-eyed female fruit fly is mated to a red-eyed male.One of their hundreds of female progeny is white-eyed.This white-eyed daughter likely arose from nondisjunction of the sex chromosomes during ________ in the ________.

Crossing-over allows the reassortment of linked genes.

Cytokinesis in plant cells occurs by means of a cleavage furrow.

In chickens, females have two different sex chromosomes (Z and W), while the males have two Z chromosomes.A Z-linked gene controls the pattern of the feathers, with the dominant B allele causing the barred pattern and the b allele causing nonbarred feathers.Which of the following crosses would produce all daughters of one type (barred or nonbarred)and all sons of the other type?

Daughter cells produced in meiosis are identical.

Orientation of each chromosomal pair on the spindle axis is random.

What aspect of chromosome behavior most clearly accounts for Mendel's law of segregation?

In fruit flies, brown eyes can be caused by recessive mutant alleles of any one of three genes: pn (prune), bw (brown)or ry (rosy).The pn gene is X-linked, bw is on the second chromosome, and ry is on the third chromosome.One wild-type allele of each of the three genes must be present for eyes to be red (wild type).Suppose that two brown-eyed flies are crossed and their progeny consist of brown-eyed sons and red-eyed daughters.Which mutation is responsible for the brown eyes in the parental female?

Which types of chromosomes provide the basis for sex determination in most mammals?

In humans, XO individuals are females with Turner syndrome and XXY individuals are males with Klinefelter syndrome.Which of the following events cannot give rise to a Klinefelter male?

Humans have 22 pairs of autosomes plus one sex chromosome pair.How many autosomes are present in a normal human primary spermatocyte?

Suppose you discover a mouse that has spiky fur instead of the usual soft fur.You notice that this trait seems to be present only in males.To investigate this pattern, you cross a spiky-fur male with a soft-fur female, and find that all the F₁ progeny of both sexes have soft fur.You then interbreed the F₁ and observe that all the F₂ females have soft fur, but 1/4 of the F₂ males have spiky fur.You conclude that the spiky allele is

Normal fruit flies have red eyes.Flies with mutations that block the function of the X-linked white gene have white eyes.The wild-type allele is completely dominant to mutant alleles.A cross between a white-eyed female fruit fly and a red-eyed male would generate which of the following types of progeny?

In which of the following cases will a Barr body be seen?