Tutorials #25-27 Questions

If two F1-hybrid pea plants with purple flowers (Pp) are crossed, what portion (expressed as a decimal) of their offspring would have white flowers (purple flowers are the dominant trait)?

.25

A true-breeding pea plant with wrinkled seeds (rr) is crossed with a pea plant that is heterozygous for round seeds (Rr). What portion (expressed as a decimal) of the offspring should have round seeds?

.5

If the P generation is AABBCC x aabbcc, what is the probability of getting an offspring with genotype AaBbcc in the F2 generation?

1/16

In a cross between AABbCc x AaBbcc parents, what is the probability of having an AaBBcc child?

1/16

In pea plants, purple flowers are dominant to white flowers. If a heterozygous purple flowered plant is crossed with a white flowered plant - what fraction of their offspring is expected to be purple?

1/2

What is the probability of getting an AB gamete from an individual who is AABb?

1/2

What is the probability that individual III-1 will have an affected child if her husband has the same genotype as individual III-7?

1/2

A plant with purple flowers and round seeds (PpRr) is crossed with a plant with white flowers and wrinkled seeds (pprr). What fraction of the offspring should have white flowers and wrinkled seeds? (Purple flowers and round seeds are dominant.)

1/4

Given two genes on different chromosomes (they assort independently), A and B, with A completely dominant to a and B completely dominant to b, what is the probability of getting an AB gamete from an individual who is heterozygous at both genes?

1/4

What is the probability of a pea plant with genotype RrYy producing a gamete with genotype ry?

1/4

Two F1-hybrid plants with yellow, round seeds (YyRr) are crossed. What is the probability of getting an offspring with the genotype YYRr?

1/8

You cross two, true-breeding parents (one with yellow peas and one with green peas). All of the F1 progeny (offspring) have yellow peas. You grow and self-pollinate this F1 generation and collect 1600 F2 progeny. How many plants with yellow peas would you expect?

1200

You cross two true-breeding parents (one with yellow seeds and one with green seeds), grow and self-pollinate the F1 generation, and then count the number of offspring with yellow and green seeds. If you counted 2,000 offspring and there was a 3:1 ratio of yellow:green seeds, how many offspring would have yellow seeds?

1500

The fruit fly Drosophila melanogaster has 3 pairs of autosomal chromosomes and an X and Y chromosome (males are XY, females are XX). How many different chromosome combinations are produced by independent assortment in D. melanogaster?

16

In water snakes, body color is controlled by two alleles that display incomplete dominance. Snakes with the BB genotype are brown, those with the Bb genotype are gray, and individuals with the bb genotype are green. If a brown snake and a gray snake are crossed, what ratio of phenotypes should be expected in the offspring?

1:1, brown:gray

The gene controlling ear color in a gizmo has two alleles that exhibit incomplete dominance: CR, which codes for red ears; and CY, which codes for yellow ears. Individuals that are homozygous for the CR allele have red ears, whereas the heterozygous genotype produces orange ears. Those that are homozygous for the CY allele have yellow ears. If two individuals with orange ears are crossed, what ratio of phenotypes should be expected in the offspring?

1:2:1, red:orange:yellow

Some cats are born without a tail - they are called Manx cats. The gene responsible for this condition is inherited as an autosomal dominant; it is lethal in the homozygous form and kittens with this genotype are not born. If two Manx cats are mated, what proportion of kittens in the litter are expected to be Manx?

2/3

A genetic cross between two F1-hybrid pea plants having yellow seeds will yield what percent green-seeded plants in the F2 generation? Yellow seeds are dominant to green.

25%

Given the counts below, what is the ratio of purple:white flowers in the following example? Purple = 770 White = 222

3.47 : 1

In some breeds of dogs, a form of progressive retinal atrophy (PRA) is inherited as an autosomal recessive disorder and causes blindness. Two dogs that are heterozygous for the PRA allele and have normal vision are mated and have a litter of puppies. What proportion of puppies in the litter will NOT become blind?

3/4

A woman with PKU is married to a man who is a carrier for the condition. If they have three children, what is the probability that one of them will have PKU and the other two will not?

3/8

If 2 mice of genotype FfGgHhIiJj are repeatedly mated, and the five genes (all inherited as a complete dominant) assort independently, how many different phenotypes will be found in the offspring?

32

You cross two true-breeding parents (one with purple flowers and one with white flowers). All of the F1 progeny (offspring) have purple flowers. You grow and self-pollinate this F1 generation and collect 500 F2 progeny. How many purple flowers should be produced?

375

How many different gamete types can an individual with genotype aaBBCcDd make?

4

A woman who is a carrier for sickle cell anemia marries a man who has the disease. They are thinking of having 4 children. What is the probability that they will have one child with the disease and three without the disease?

4/16

Your friend wants to have four children. What is the probability that she will have 3 girls and 1 boy?

4/16

A man with cystic fibrosis and a woman who is a carrier for the disease have two children with cystic fibrosis. What is the probability that their next child will have the disease?

50%

If one parent who has Huntington's disease is heterozygous for the trait and the other parent is not affected, what are the chances of their offspring inheriting the trait?

50%

Two F1-hybrid plants with purple flowers and round seeds (PpRr) are crossed. If 1,000 randomly chosen offspring from this cross are examined, how many should have white flowers and wrinkled seeds (purple flowers and round seeds are the dominant traits)? You may need to round off your answer to the nearest whole number.

63

How many different genotypes will be found in the offspring of a plant with the genotype AaBbCCDDee if it undergoes self-fertilization?

9

From a cross of two people heterozygous at two different genes that assort independently, what is the probability of having a child that expresses the dominant phenotype for both genes?

9/16

In a cross of two F1-hybrid plants with purple flowers and round seeds (PpRr), what fraction of the offspring should have purple flowers and round seeds (purple flowers and round seeds are the dominant traits)?

9/16

In a cross between a female AaBbccDdee and a male AabbCcDdee, what proportion of the offspring will be phenotypically identical to the female parent? (Assume independent assortment of all genes and complete dominance).

9/64

You cross two true-breeding parents, one with purple flowers and one with white flowers, grow and self-pollinate the F1 generation, and then count the number of offspring with purple and white flowers in the F2 generation. If you counted 1,200 offspring and there was a 3:1 ratio of purple:white flowers, how many offspring would have purple flowers?

900

In pea plants, green pods (G) are completely dominant to yellow pods (g). You have a plant with green pods but are not sure of its genotype for pod color. Which of the following pea plants would you cross it with to determine if this plant with green pods is homozygous or heterozygous at the pod color gene?

A true breeding plant with yellow pods.

What possible blood types could offspring have if their two parents have the blood types A and AB, respectively?

A, B, AB

If a person with blood type A and a person with blood type B have a child, what are the possible blood types that child could have?

A, B, AB, O

Two plants have different phenotypes and genotypes. One is heterozygous while the other is true-breeding for the same trait. You cross these two plants. What will be the phenotype of the progeny?

Half will show the phenotype of the true-breeding plant, half will show the phenotype of the heterozygote.

Which meiotic process results in the Law of Segregation?

Homologous chromosomes separate during Meiosis I.

Which of the following genotype(s) would result in an individual with the type A blood phenotype?

IAIA, Iai

Which meiotic process results in the Law of Independent Assortment?

Non-homologous chromosomes segregating into daughter cells independently of each other.

The effects of ___________ can be almost completely overcome by regulating the diet of the individual from infancy.

Phenylketonuria

You have a pea plant that exhibits the dominant trait of green pods. You cross this plant to a true-breeding plant with the recessive trait of yellow pods. Half of the offspring from this cross have green pods and the other half have yellow pods. Which of the following statements is true?

The parent with green pods had the genotype Gg.

When Mendel crossed a true-breeding purple-flowered pea plant with a true-breeding white-flowered pea plant, he observed that all of the F1 offspring had purple flowers. When these F1 plants were selfed, he found 3/4 were purple and 1/4 were white. Which of the following observations supports Mendel's conclusion that each progeny can carry two alternative copies of a "factor"?

When the purple progeny are selfed, both white and purple progeny result.

Fur color in mice is determined by the same two genes that determine coat color in Labrador retrievers (gene B for coat color and gene E for deposition of pigment). If a brown female (her father was white) is crossed with a black male from a true breeding line, what colors and proportions would you expect in their offspring?

all black

This pedigree shows the occurrence of deafness in 3 generations of a family. What is the most likely mode of expression for this form of deafness?

autosomal recessive

A plant that is true-breeding for a particular trait would __________.

be homozygous for that trait

Mice with the genotypes BBCc and bbcc are crossed. The alleles for brown coat (b) and no pigment (c) are recessive, and black coat (B) is dominant. What color of mice would NOT be produced by this mating?

brown

A character trait that behaves in a completely dominant manner

can be seen in the heterozygous state.

You are examining a trait which shows three distinct phenotypes, with the phenotype of heterozygotes expressing both alleles seen in the homozygotes. This is an example of:

codominance

What type of dominance best explains a phenotypic ratio of 1:2:1 in the F2 generation of a monohybrid cross for a character with two traits (two alleles)? Select all that apply.

codominance or incomplete dominance

________________ is an example of a recessive inherited trait.

cystic fibrosis

Does this pedigree most likely show a dominant or recessive condition?

dominant

A gene that affects the expression of a second gene is an example of _____.

epistasis

Which of the following is not a character in pea plants?

green pods

A monohybrid cross between two heterozygous individuals yields a 3:1 phenotypic ratio if the alleles exhibit complete dominance. However, a 1:2:1 phenotypic ratio is observed if the alleles show incomplete dominance. This is because

heterozygotes have an intermediate phenotype between both homozygotes.

What is the most likely genotype of individual #5?

heterozygous for this disorder, which is expressed as a recessive trait.

In this pedigree showing the inheritance of a genetic disorder within a family, the genotype of the individual marked "IVA" is most likely

homozygous recessive for this disorder, which shows recessive inheritance.

This disorder is caused by a dominant mutation at an autosomal gene. It leads to progressive neurological degeneration and death, but symptoms do not begin to appear until later in life.

huntington's disease

An individual that is heterozygous for an allele and that exhibits a phenotype intermediate between that of the two homozygous alternatives is an example of _____.

incomplete dominance

The idea that different pairs of alleles are passed to offspring independently is Mendel's Law of

independent assortment

You examine a population of plants that have been interbreeding for several generations. You notice that some plants are totally green, while others also have a prominent red hue. A closer look reveals a gradient of red hue intensity across the population. This trait appears heritable because in each generation you notice the same gradient. The red hue is most likely caused by

multiple genes

Does the Law of Independent Assortment apply to a single character (gene)?

no

In the pentahybrid cross between individuals with the genotype AaBbCCDdEe X AabbCcDdEe, what proportion of their offspring with have the genotype AAbbccDdEe.

not possible

In garden peas, a single gene determines seed shape (round or wrinkled); this gene also influences the form of starch grains within the seed. This is an example of

pleiotropy

Type 1 Albinism is inherited as an autosomal recessive trait and its symptoms include lack of pigmentation in the hair, eyes and skin, abnormal development of the retina (affecting vision), a jerky motion of the eyes (nystagmus), photophobia, and an increased risk of skin cancer. Based upon this information, you can conclude that albinism is an example of

pleiotropy

__________ is an example of a character that is controlled by more than one gene (a quantitative character) and demonstrates a continuum of phenotypes.

polygenic inheritance

To determine if a plant with purple flowers is homozygous (PP) or heterozygous (Pp) for that trait, one would do a test cross with plants of the _____ genotype.

pp

What is the probability of an individual with the genotype IAi producing a child with type O blood?

question cannot be answered

Does this pedigree most likely show a dominant or recessive condition?

recessive

You have two rose plants, both with pink flowers. You cross the two plants and are surprised to find that, while most of the offspring are pink, some are red and some are white. You decide that you like the red flowers and would like to make more. What cross would you perform to produce the most red flowered plants?

red x red

The idea that for any particular trait, the pair of alleles of each parent separate and only one allele from each parent passes to an offspring is Mendel's Law of

segregation

Which of the following would Mendel have described as a character for pea plants?

stem length

A recessive trait __________________________. (Select all that apply)

tends to skip generations in a pedigree. is only expressed in the homozygous state.

You are given two plants. One plant is tall and the other is short. You cross these parentals and find all F1 progeny are tall. You cross the F1 progeny with one another and find the resulting F2 generation is composed of 770 tall plants and 300 short plants. You should conclude that ___________.

the F1 plants are heterozygous, and tall is dominant to short

Mendel's Law of Independent Assortment states that _____.

the alleles for different characters segregate randomly from one another during gamete production

A phenotypic ratio of 3:1 in the offspring of a mating of two organisms is expected when ___________________. Select all that apply.

the alleles segregate during meiosis. both parents are heterozygous.

An individual who is heterozygous for gene R (Rr) produces two types of gametes in regard to these alleles: R and r. This illustrates

the law of segregation

In a cross between a true breeding purple pea plant and a true breeding white pea plant

the purple trait is completely dominant to the white trait.

A man with type AB blood marries a woman with type 0 blood. Which of the following blood types would be possible in their children?

type A and B

In squash, color is determined by two genes that are epistatic. At the first gene, white squash (W) is dominant to colored squash (w). At the second gene, yellow (Y) is dominant to green (y). A squash that is green must have the genotype:

wwyy

A "Real Life Example" Question: Fur color in Labrador retrievers is determined by two genes (gene B for coat color and gene E for deposition of pigment). Nose, lip and gum color is determined only by gene B. A yellow female with brown nose and gums is mated with a brown (chocolate) male whose mother was yellow. What are their possible offspring?

½ yellow and ½ brown - all with brown noses.