AP Bio Ch. 14-15

A couple has tree children, all of whom have brown eyes and blond hair. Both parents are homozygous for brown eyes (BB), but one is blond (rr) and the other is a redhead (Rr). What is the probability that their next child will be a brown-eyed redhead?

1/2

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 son will be color-blind?

1/2

A woman and her spouse both show the normal phenotype for pigmentation, but both had one parent who was an albino. Albinism is an autosomal recessive trait. What is the probability that their fourth child will have a homozygous genotype?

1/2

Black fur in mice (B) is dominant to brown fur (b). Short tails (T) is dominant to long tails (t). What fraction of the progeny of the cross BbTt x BBtt will have black fur and long tails?

1/2

A woman and her spouse both show the normal phenotype for pigmentation, but both had one parent who was an albino. Albinism is an autosomal recessive trait. If their first two children have normal pigmentation, what is the probability that their third child will be an albino?

1/4

Albinism (lack of skin pigmentation) is caused by a recessive autosomal allele. A man and woman, both normally pigmented, have an albino child together. The couple decided to have a second child. What is the probability that his child will be albino?

1/4

In a cross AaBbCc x AaBbCc, what is the probability of producing the genotype AABBCC?

1/64

In snapdragons, heterozygotes have pink flowers, whereas the two homozygotes have red flowers or white flowers. When plants with red flowers are crossed with plants with white flowers, what proportion of the offspring will have pink flowers?

100%

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

100%

A couple who are both carriers of the gene for cystic fibrosis have two children who have cystic fibrosis. What is the probability that their next child will have cystic fibrosis?

25%

In birds, sex is determined by a ZW chromosome scheme. Males are ZZ and females are ZW. A lethal recessive allele that causes death of the embryo occurs on the Z chromosome in pigeons. What would be the sex ratio in the offspring of a cross between a male heterozygous for the lethal allele and a normal female?

2:1 male to female

Given the parents AABBCc x AabbCc, assume simple dominance and independent assortment. What proportion of the progeny will be expected to phenotypically resemble the first parent?

3/4

How many unique gametes could be produced through independent assortment by an individual with the genotype AaBbCCDdEE?

8

Albinism (lack of skin pigmentation) is caused by a recessive autosomal allele. A man and woman, both normally pigmented, have an albino child together. The mother is now pregnant for a third time, and her doctor tells her she is carrying fraternal twins. What is the probability that both children will have normal pigmentation?

9/16

Feather color in budgies is determined by two different genes that affect the pigmentation of the outer feather and its core. Y_B_ is green; yyB_is blue; Y_bb is yellow; and yybb is white. A green budgie is crossed with a blue budgie. Which of the following results is not possible?

All of the above (all green, all blue, all white, and all yellow) are possible, but with different possibilities.

A woman who belongs to blood group A and is Rh positive has a daughter who is O positive and a son who is B negative. Rh positive is a simple dominant over Rh negative. Which of the following is a possible phenotype for the father?

B positive

In a cross between parents who both exhibit the dominant curly-and dark-haired traits, one child has straight, light-colored hair. What are the hair genotypes of the parents?

CcDd x CcDd

This is caused by a dominant single gene defect and generally does not appear until the individual is 30-40 years of age.

Huntington's disease

A woman who belongs to blood group A and is Rh positive has a daughter who is O positive and a son who is B negative. Rh positive is a simple dominant over Rh negative. Which of the following is a possible genotype for the son?

IBirr

Roan color in cattle is the result of incomplete dominance between red and white color genes (Rr). How would one produce a herd of pure breeding roan-colored cattle?

It cannot be done.

Which of the following statements is true regarding genomic imprinting?

It explains cases where the gender of the parent from whom an allele is inherited the expression of that allele.

Tallness (T) is dominant to dwarfness (t), while red (R) flower color is dominant to white (r). The heterozygous condition results in pink (Rr) flower color. A dwarf, homozygous red snapdragon is crossed with a plant homozygous for tallness and white flowers. What are the genotype and phenotype of the F2 individuals?

TtRr_ tall and pink

A 9:3:3:1 phenotypic ratio is characteristic of

a dihybrid cross.

Most calico cats are females because

a male inherits only one of the two X-linked genes controlling hair color.

What is a genetic cross called between an individual of unknown genotype and a homozygous recessive?

a testcross

A man who carries an X-linked allele will pass it on to

all of his daughters.

Feather color in budgies is determined by two different genes that affect the pigmentation of the outer feather and its core. Y_B_ is green; yyB_is blue; Y_bb is yellow; and yybb is white. The inheritance of color in budgies is an example of what genetic phenomenon?

epistasis

There is good evidence for linkage when

genes do not segregate independently during meiosis.

Albinism (lack of skin pigmentation) is caused by a recessive autosomal allele. A man and woman, both normally pigmented, have an albino child together. For this trait, what is the genotype of the albino child?

homozygous recessive

The phenotype of the heterozygote differs from the phenotypes of both homozygotes.

incomplete dominance

People who have red hair usually have freckles. This can best be explained by

linkage.

One example is the ABO blood group systems.

multiple alleles

Male calico cats are the result of

nondisjunction, where the male calico presumably has two X chromosomes

An achondroplastic dwarf man with 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. Achondroplastic dwarfism is autosomal dominant, and red-green color blindness is X-linked recessive. How many of their female children might be expected to be color-blind dwarfs?

none

Effects of this recessive single gene can be completely overcome by regulating the diet of the affected individual.

phenylketonuria

The ability of a single gene to have multiple phenotype effects.

pleiotrophy

The frequency of crossing over between any two linked genes is

proportional to the distance between them.

In cattle, roan coat color (mixed red and white hairs) occurs in the heterozygous (Rr) offspring of red (RR) and white (rr) homozygotes. When two roan cattle are crossed, the phenotypes of the progeny are found to be in the ratio of 1 red:2 roan:1 white. Which of the following crosses could produce the highest percentage of roan cattle?

red x white

The fact that all seven of the garden pea traits studied by Mendel obeyed the principle of independent assortment means that the

seven pairs of alleles determining these traits behave as if they are on different chromosomes.

Substitution of the "wrong" amino acid in the hemoglobin protein results in this disorder.

sickle-cell disease

A Barr body is normally found in the nucleus of which kind of human cell?

somatic cells of a female only

To what does independent assortment refer?

the random assortment of chromosomal tetrads at metaphase 1

If inheritance of a human trait is sex-linked (on the X chromosome) and recessive, any of the following could result except that

the trait could be more common in females than males.

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

tortoiseshell female; black male