chapter 16

25問 • 1年前

問題一覧

The agouti gene, when expressed in mice, makes them obese, ravenous, yellow, and prone to diabetes. The agouti phenotype is dominant. During ovulation an agouti mouse is given a drug that methylates (or shuts off) the agouti gene. She is then bred to another mouse and gives birth to a litter of baby mice, none of whom have the agouti phenotype. Which of the following is accurate?

All of these choices are correct.

The best way to distinguish an epigenetic effect from other types of gene regulation would be to

confirm that the change in gene expression is passed from cell to cell but does not involve a change in the DNA sequence.

Epigenetic inheritance

can result in the expression of different alleles in different generations.

Recall that in mice the Ig2 gene exhibits genomic imprinting where the maternal allele is silenced by DNA methylation. What is the probability that a mouse pup (male or female) from the male offspring of a homozygous dwarf female (Ifg2° lg(2) and a heterozygous normal-size male (Igf2 lg(2) is normal-sized as well?

50%

A black female cat (×B and an orange male cat (X) were mated to each other and produced a rare male calico cat. Which sex chromosome(s) did the male inherit from its female parent? (Remember the presence of the Y chromosome determines maleness in mammals.)

If a male cat with orange fur produces female offspring with calico fur, what color was the female parent?

Black or calico

A black female cat (XBx and an orange male cat (XoY) were mated to each other and produced a rare male calico cat. What occurred during gamete production to produce this cat?

The sex chromosomes didn't separate during meiosis in the male parent.

Which of the following is evidence supporting the Lyon hypothesis of X inactivation?

All of these choices are correct.

A gene for sweat gland production is located on the X chromosome. A male who lacks sweat glands marries a female who has normal sweat glands. Which of the following are possible phenotypes of their children?

The females will be mosaic; they will have patches of skin with sweat glands and patches of skin lacking sweat glands.

In cats, the gene for coat color is found on the X chromosome. A mass of cells is shown making up an early female cat embryo. The X chromosomes are shown in each cell; this embryo has one orange coat color allele (O) and one black coat color allele (B). Which of the following is ACCURATE about this embryo?

It will give rise to a calico cat.

Barr bodies

are formed in females.

The karyotype of a young patient shows two Barr bodies per cell. What condition might this child have?

Triple X syndrome

How do dietary factors interact with DNA methyltransferase to affect an organism's phenotype in an epigenetic manner?

Some dietary factors inhibit DNA methyltransferase activity, reducing the methylation of the organism's DNA and changing its gene expression

The genomes of mammalian mitochondria contain

All of these choices are correct.

A male has a mutation in a mitochondrial gene encoding a subunit of the ATP synthase complex. The mutation leads to a defective ATP synthase that is not able to synthesize ATP effectively, and this in turn leads to extreme muscle weakness in the affected individual. If this male has children, what is the likelihood that they will inherit this disease from him?

In plants, most chloroplasts are inherited from the maternal plant because maternal gametes contribute the most ______ to the zygote

cytoplasm

If a plant species exhibits maternal inheritance for leaf pigmentation, what is the phenotype of the parents of a variegated (green and white leaves) plant?

The maternal plant must be variegated and the paternal plant can be any color.

Which of the following diseases is not caused by a mutation in a mitochondrial gene?

turner syndrome

In dogs, there is a hereditary deafness caused by a recessive allele, d. A kennel owner has a male dog that she wants to use for breeding purposes if possible. The dog can hear, but the owner is unsure of the genotype. She does a testcross (crosses it to a homozygous recessive dog), and two of the five offspring are deaf. This means that the male dog

has the genotype Dd.

You breed a black, long-haired rabbit with a white, short-haired rabbit. All of the offspring have long, black hair. If the genes for hair color and length are closely linked on the same chromosome, what would you expect to see in the F2 generation?

15 black, long-haired: 1 black, short-haired: 1 white, long-haired: 5 white, short-haired

The inheritance pattern where two or more genes do not assort independently because they are close together on the same chromosome is called

linkage

What is a testcross?

A cross between an organism of unknown genotype with a homozygous recessive individual

Which of the following statements is not one of Morgan's key ideas about independent assortment?

Linked genes are always inherited together.

In the sweet pea crossing experiment by Bateson and Punnet, the F2 generation had many more offspring with the phenotypes of purple flowers with long pollen (PL) and red flowers with round pollen (of than expected from independent assortment. This is because

in sweet peas, the alleles for flower color and pollen shape are on the same chromosome.

How can you determine the genotype of a plant showing the dominant phenotype of red color?

Cross the red plant with a white plant to see if any white plants appear.

chapter 21

Madeline Joslyn · 46回閲覧 · 25問 · 1年前

chapter 21