chapter 15

25問 • 1年前

問題一覧

What is a dominant allele?

In a heterozygous individual, the allele that determines the phenotype

Nearsightedness is dominant to normal vision and hazel eyes are dominant to blue eyes. A female who is nearsighted with hazel eyes and is heterozygous for both traits has children with a male who has normal vision and hazel eyes. He is heterozygous for eye color. Their three children all have blue eyes and normal vision. What is the probability that their next child will have blue eyes and be nearsighted?

1/8

The probability of obtaining a dominant phenotype from self-fertilization of a heterozygous individual is

75%

What is a possible distribution of phenotypes from a cross of purple tall pea plants that are heterozygous for flower color and plant height? (Purple is dominant white; tall is dominant to dwarf.)

63 purple tall: 28 purple tall: 27 white tall: 7 white dwarf

What quality of the traits that Mendel chose to study allowed him to establish the basic laws of inheritance?

The alleles that he studied were either dominant or recessive.

Anury is the absence or abbreviation of the tail in sheep (and also other animals). It is inherited in an autosomal dominant fashion. A ram with anury is mated to a ewe with a normal tail. The ram's male parent had anury, its female parent did not. What is the probability that the ram and ewe will produce a lamb with anury? (ram =male; ewe = female)

50%

Eyelash length is an inherited trait. In the human population, there is an eyelash length gene. There are two possible variants of this gene--an allele for long eyelashes (1cm) and an allele for short eyelashes (1 cm or less). The allele for long eyelashes is dominant (L) and the allele for short eyelashes is recessive (1. An individual who is heterozygous for eyelash length would have which of the following genotypes?

Mendel used garden peas to study inheritance patterns, but other plants would have worked as well. Study the characteristics of the plants below, and determine which would be the best model organism to study inheritance patterns.

Impatiens are common garden annuals that produce copious numbers of bright flowers throughout the growing season. Their flowers come in an array of different colors, they are self-fertile, and produce a fruit that is sensitive to the touch. When it is ripe, the lightest touch will cause the capsule to spring open and explosively release up to 100 seeds in all directions. This dramatic seed dispersal mechanism has given rise to its common name, touch-me-not. Impatiens have fast generation times, and a germinated seed can produce flowers in about 6 weeks.

Eyelash length is an inherited trait. In the human population, there is an eyelash length gene. There are two possible variants of this gene-an allele for long eyelashes (im) and an allele for short eyelashes (1 cm or less). The allele for long eyelashes is dominant (L) and the allele for short eyelashes is recessive (1). An individual who is heterozygous for eyelash length would produce which of the following gametes?

Half of the gametes would have the L allele and half of the gametes would have the /allele.

The two-factor crosses performed by Mendel support the observation that

alleles of one gene are distributed randomly among an individual's gametes, independent of the alleles for other genes

In wolves, gray coat color (G) is dominant to black (g) and brown eyes (B are dominant to blue (b). The genes that control these traits are located on different chromosomes. The alpha male of the pack has the dominant phenotype for both traits and is heterozygous for both traits. The alpha female has brown eyes and a black coat: she is heterozygous for eye color. The alpha male and the alpha female mate. What proportion of their offspring will have the same phenotype as the mother?

3/8

Eyelash length is an inherited trait. In the human population, there is an eyelash length gene. There are two possible variants of this gene-an allele for long eyelashes (im) and an allele for short eyelashes (1 cm or less). How many eyelash length alleles does an individual have in a somatic cell?

A male is heterozygous for the trait that produces freckles on the skin, and he has freckles. If has children with a female who is also heterozygous for freckles, ______ percent of their children are predicted to be freckled. Also, of all their children, ______ percent are predicted to be heterozygous.

75%, 50%

In wolves, gray coat color (G) is dominant to black (g) and brown eyes (B) are dominant to blue (b). The genes that control these traits are located on different chromosomes. The alpha male of the pack has the dominant phenotype for both traits and is heterozygous for both traits. The alpha female has brown eyes and a black coat; she is heterozygous for eye color. Which option represents gametes that would be made by the alpha female?

Bg and bg

What features of meiosis allow for independent assortment of chromosomes?

Random alignment of homologous chromosomes on the metaphase plate

Huntington's disease (HD) is a fatal neurological disease that is inherited in an autosomal dominant manner. Most people with HD develop signs and symptoms in their late 30s or early 40s, but the onset of disease may be earlier or later in life. A 20-year-old female comes to your genetic counseling center because she knows that HD occurs in members of her family. Her paternal male grandparent was afflicted, but so far her 41-year-old male parent shows no symptoms. Her two paternal great-great female grandparents were healthy well into their 90s, and one of her great-great male grandparents died of unknown causes at 50. Testing for HD is extremely expensive, but she is concerned that she may fall victim to this disease and wants to plan her life accordingly. After examining her pedigree you advise her to

get tested because her male parent could be heterozygous for the HD allele.

Polydactyly is a dominant trait that results in extra fingers and toes in humans. A male with polydactyly has a child with a female who has 10 fingers and toes. The that has 10 fingers and toes. The male's female parent had 10 fingers and toes but his male parent's phenotype was unknown. What are the genotypes of the couple? (D = polydactyl allele; d = wild type allele)

female dd, male Dd

Roberts syndrome is an extremely rare genetic disorder that is characterized by mild to severe prenatal intellectual disabilities or disruption of cell division, leading to malformation of the bones in the skull, face, arms, and legs. Shown below is a pedigree for a family with Robert's syndrome. What is the genotype of individual IC? (R = wild type; r = Robert's syndrome)

Two identical twin kittens were left at an animal shelter and were later adopted by different families. One twin grew up in a stable a loving family home and was well fed and well cared for. The other twin was abandoned soon after and ended up living on the streets. After more than 5 years, the two twins were reunited, but despite their identical genomes, the twins looked very different. The most noticeable difference was their difference in stature, the cat reared in the home was larger and stronger, while the feral cat was smaller and scrawny. How can you explain these differences?

The feral twin was undernourished as a kitten, and as a result was unable to reach the full potential of its genes.

Imagine that horn color in Hodags (folkiorie creatures) is controlled by a single gene so that when a Hodag homozygous for bright orange horns (COcO mates with a Hodag homozygous for ivory horns (C'c), numerous offspring are produced, all with pale orange the F1 generation. Two F1 Hodags mate with each other. What phenotypes do you expect?

1 bright orange: 2 pale orange: 1 ivory

The color of petunia flower can be changed from red to blue by altering the pH of the soil. This is an example of

the environment influencing the phenotype

An organism has one Z chromosome and one W chromosome. That organism is

a female bird

An X-linked gene is

a gene on the X chromosome.

Hemophilia is a sex-linked recessive condition that results in deficient blood clotting. The disease causes excessive bleeding which occurs spontaneously or upon slight injury. In dogs (as in humans) hemophilia is caused by a defect in a gene on the X chromosome. What will be the results of mating between a normal, non-carrier female dog and a male dog with hemophilia?

All of the offspring will be normal, but all females will be carriers.

For mechanisms of sex determination, which of the following is incorrectly paired?

1n-2n, pea plant

chapter 21

Madeline Joslyn · 46回閲覧 · 25問 · 1年前

chapter 21