Mastering Chapter 15

A cell goes through S phase, meiosis I, and cytokinesis. As the daughter cells are beginning meiosis II, which of the following is an appropriate description of the contents of each cell?

During a single crossover event, how many strands of DNA must break? (Recall that DNA is double-stranded.)

A white-eyed female Drosophila is crossed with a red-eyed male Drosophila. Which statement below correctly describes the results? See Concept 15.1 (Page)

When Thomas Hunt Morgan crossed his red-eyed F1 generation flies to each other, the F2 generation included both red- and white-eyed flies. Remarkably, all the white-eyed flies were male. What was the explanation for this result?

In humans, what determines the sex of offspring and why? See Concept 15.2 (Page)

The SRY gene is best described as ________.

In cats, black fur color is determined by an X-linked allele; the other allele at this locus determines orange color. The heterozygote is tortoiseshell. What kinds of offspring would you expect from the cross of a black female and an orange male?

Red-green color blindness is a sex-linked recessive trait in humans. Two people with normal color vision have a color-blind son. What are the genotypes of the parents?

White eye color is a sex-linked, recessive characteristic in fruit flies. If a female having white eyes is crossed with a wild-type male, what percentage of the F1 males will have white eyes?

Generally, only female cats have the tortoiseshell phenotype for fur color. Which of the following statements explains this phenomenon?

Sex determination in mammals is due to the SRY gene found on the Y chromosome. Which of the following situations could allow a person with an XX karyotype to develop a male phenotype?

Duchenne muscular dystrophy is a serious condition caused by a recessive allele of a gene on the human X chromosome. The patients have muscles that weaken over time because they have absent or decreased dystrophin, a muscle protein. They rarely live past their 20s. How likely is it for a woman to have this condition?

A recessive allele on the X chromosome is responsible for red-green color blindness in humans. A woman with normal vision whose father is color blind marries a color-blind male. What is the probability that this couple's first son will be color blind?

Which of the following individuals will inherit an X-linked allele from a man who carries it?

Part A A man who is a dwarf with achondroplasia and normal vision marries a color-blind woman of normal height. The man's father was six feet tall, and both the woman's parents were of average height. Dwarfism caused by achondroplasia is autosomal dominant, and red-green color blindness is X-linked recessive. How many of their daughters might be expected to be color-blind with achondroplasia?

Which of the following statements regarding gene linkage is correct?

What does a recombination frequency of 50% indicate?

Genes that are farther apart on a chromosome have more combination possibilities - T or F?

Which of the following statements correctly describes the reason that closely linked genes are typically inherited together?

What results if a fragment of a chromosome breaks off and then reattaches to the original chromosome at the same place but in the reverse direction? See Concept 15.4 (Page)

A couple has a child with Down syndrome. The mother is 39 years old at the time of delivery. Which of the following is the most probable cause of the child's condition?

A woman is found to have 47 chromosomes, including three X chromosomes. Which of the following statements describes her expected phenotype?

How are human mitochondria inherited? See Concept 15.5 (Page)

Which of the following is true of an X-linked gene, but not of a Y-linked gene? See Concept 15.2 (Page)

Which of these descriptions of the behavior of chromosomes during meiosis explains Mendel's law of segregation?

Which of these descriptions of the behavior of chromosomes during meiosis explains Mendel's law of independent assortment?