Deck 17: Complex Patterns of Inheritance

Question 1

You are breeding different varieties of roses in your garden. When you cross a true-breeding yellow "Texas Beauty" rose with a true-breeding "Ruby" red rose, you get all red roses. But when you cross a "Texas Beauty" yellow with the yellow variety "Jealousy," you get a 9:7 ratio of red to yellow flowers! What can you conclude from these results?

A) The environment, and not genes, influences pigment in these rose varieties.
B) There are epistatic interactions between at least two genes for rose pigment.
C) The red allele is dominant to the yellow allele.
D) There is a mutation in the gene for yellow pigment in the "Jealosy" variety.
E) There is no recessive allele for the red pigment gene.

Answer 1

There are epistatic interactions between at least two genes for rose pigment.

Question 2

Which of the following statements correctly describes a quantitative trait?

A) People who are homozygous for the group of genes associated with skin pigment have either lighter . or darker skin than those who are heterozygous for those genes.
B) The alleles of the gene for red hair color is masked by the gene for brown hair color.
C) A person heterozygous for dwarfism will always have the dwarf phenotype.
D) A woman who has one allele for color blindness will not be color blind, but a man who has one allele for color blindness will be color blind.
E) 25% of the offspring from a cross of two fruit flies that are heterozygous for curly wings will have curly wings.

Answer 2

People who are homozygous for the group of genes associated with skin pigment have either lighter . or darker skin than those who are heterozygous for those genes.

Question 3

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 linked, what would be a possible ratio for the F₂ population?

A) 5 long-haired black, 4 short-haired white, 1 short-haired black, 2 long-haired white
B) 3 long-haired black, 1 short-haired white, 1 short-haired black, 3 long-haired white
C) 5 long-haired black, 4 short-haired white, 5 short-haired black, 4 long-haired white
D) 1 long-haired black, 1 short-haired white, 1 short-haired black, 1 long-haired white
E) 1 long-haired black, 2 short-haired white, 5 short-haired black, 4 long-haired white

Answer 3

5 long-haired black, 4 short-haired white, 1 short-haired black, 2 long-haired white

Question 4

If a testcross for two different traits produces more nonrecombinant than recombinant offspring, then the alleles for the two traits

A) are dominant.
B) are on the same chromosome.
C) are on different chromosomes.
D) are epistatic.
E) are both dominant and on the same chromosome.

Question 5

You are mapping the location of two genes in Drosophila, listless l and blind b. (l+ l+ b+ b+) and (l+ l- b+ b-) flies are normal, but ( l- l- b- b-) flies don't move around very much and cannot detect the location of a light source. You perform a testcross and get the following results: listless, sighted 100 listless, blind 400 normal activity, sighted 400 normal activity, blind 100 What is the distance between these two genes on the chromosome?

A) They are on different chromosomes.
B) They are 10 map units apart.
C) They are 20 map units apart.
D) They are 40 map units apart.
E) They are 80 map units apart.

Question 6

Bicoid is a maternal effect gene that is essential for the development of head structures in Drosophila. The F₁ generation from a cross of two phenotypically normal flies produces normal embryos, but in the F₂ cross, 25% of the embryos lack heads and die. What was the genotype of the mother in the P generation?

A) BB
B) Bb
C) bb
D) Either BB or Bb
E) Either Bb or bb

Question 7

Albinism in most animals is an epistatic trait characterized by a lack of melanin pigment in the eyes, skin, and hair. If the allele for albinism is a, the allele for brown coat color is B, and the allele for red coat color is b, which of the following genotypes would result in an albino cow?

A) AaBb
B) aaBB
C) aabb
D) Aabb
E) aaBB and aabb

Question 8

Quantitative traits

A) are polygenic.
B) encode genes for continuous traits.
C) are influenced by the environment.
D) are both polygenic and influenced by the environment.
E) are correctly described by all of these statements.

Question 9

Height (tallness) in humans is a polygenic trait. Assume the following: There are 4 genes that determine height (Aa, Bb, Cc, Dd). Each dominant allele adds 2 inches of height to an individual. The height of the recessive individual (aa, bb, cc, dd) is 5 feet. What is the height of a person with the genotype (AA, Bb, cc, DD)?

A) 5?4²
B) 5?10²
C) 5?8²
D) 6?6²
E) 5?6²

Question 10

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

A) Leber's Inherited Optic Neuropathy (LHON)
B) secretion of lactic acid into the bloodstream: "lactic acidosis"
C) myoclonic epilepsy
D) cardiomyopathy
E) Turner syndrome

Question 11

You discover a gene that results in a complete lack of hair in rats, and you name the gene "chromedome." A cross of homozygous normal and homozygous bald rats results in all bald rats. You conclude that the baldness allele is dominant, but when you repeat the cross with different rats none of the offspring are bald. Extremely puzzled you study your records and discover that in the first cross the bald rat was female, while in the second cross the bald rat was male. What do you conclude from this information?

A) Chromedome is imprinted in females.
B) Chromedome is imprinted in males.
C) Chromedome is dominant in males and recessive in females
D) Chromedome is dominant in males and recessive in females.
E) Chromedome is an X-linked gene.

Question 12

DNA methylation of a gene during spermatogenesis would result in

A) the inactivation of the paternal allele in the offspring.
B) dosage compensation by the paternal allele.
C) the inactivation of the maternal allele in the offspring.
D) the inactivation of the X chromosome.
E) dosage compensation by the maternal allele.

Question 13

Which of the following is NOT a type of epigenetic inheritance?

A) maternal effect
B) X inactivation
C) imprinting
D) extranuclear inheritance
E) neither maternal effect nor extranuclear inheritance

Question 14

Black-cheeked BC zebra finches are extremely desirable, but relatively rare. This phenotype is caused by a recessive mutation, but the mating of two BC birds is considered unethical because it results in very small birds. Therefore, BC birds are created by crossing carriers of the BC gene. Despite problems with the homozygous recessive, some unscrupulous breeders continue to breed them together because of the high prices they fetch. Which of the following statements could explain why BC homozygous birds are unusually small?

A) The BC gene causes a mutation in a growth gene.
B) The BC gene and a gene for growth are very close to one another on the same chromosome.
C) The BC gene and a gene for growth are both mutated.
D) The dominant version of the cheek color gene (GC) encodes a gene for normal size.
E) The BC gene and growth gene are close together on the same chromosome and/or both of these genes are mutated.

Question 15

If the recombination frequency between gene A and B is 10 out of 100 offspring, gene A and C is 30 out of 100 offspring, and gene B and C is 40 out of 100 offspring, what is the location of these genes in relation to each other on a chromosome?

A) CAB
B) BAC
C) ABC
D) CBA
E) either CAB or BAC

Question 16

A trait that is expressed as a continuum rather than as a few discrete phenotypes is

A) polygenic.
B) sex-linked.
C) codominant.
D) Mendelian.
E) either polygenic or codominant.

Question 17

A horticulturist is breeding a new variety of houseplant in which two genes control leaf color. G (allele for green) is dominant to g (yellow) and B (second allele for green) is dominant to b (yellow). The recessive homozygous condition of either gene will mask a dominant allele. What color is a plant with the genotype GgAa?

A) green
B) yellow
C) an intermediate yellow-green
D) variegated (yellow and green spots or stripes)
E) The color cannot be determined with the information given.

Question 18

An experimenter crosses two fruit flies with different phenotypes. The results in the F2 generation are: 478 crooked legs, trembling behavior 372 stumpy legs, circling behavior 175 crooked legs, circling behavior 98 stumpy legs, trembling behavior What were the genotypes / phenotypes in the Parental generation?

A) Both parents homozygous / Female phenotype: crooked legs, trembling, Male phenotype: stumpy legs, circling
B) Both parents homozygous / Male phenotype: crooked legs trembling, Female phenotype: stumpy legs, circling
C) Both parents heterozygous / Female phenotype: crooked legs, trembling, Male phenotype: crooked legs, trembling
D) Both parents homozygous / Male or female parental phenotype: crooked legs, trembling, Second parental phenotype: stumpy legs, circling
E) Both parents heterozygous / Both parental phenotypes: crooked legs, trembling

Question 19

Maternal effect genes are inherited via the mitochondria.

Question 20

Epistasis often involves genes of an enzymatic pathway.

Question 21

Genomic imprinting can result in offspring with identical genotypes that have different phenotypes.

Question 22

Mendel's laws do not adequately explain all the patterns of inheritance.

Question 23

The DNA methylation state of a zygote will be maintained throughout the life of the organism and then passed on unchanged to its offspring.

Question 24

Epistatic gene interactions do not follow Mendel's laws of inheritance.