Question 1

The phenotypic ratio 2:1 may indicate

Accepted Answer

A) complete dominance. 
B) codominance. 
C) epistasis. 
D) recessive lethal. 
E) codominance and epistasis only. 
A) complete dominance. 
B) codominance. 
C) epistasis. 
D) recessive lethal. 
E) codominance and epistasis only. D

Question 2

A certain disease is caused by homozygosity of the g allele (G is the corresponding wild-type allele).However, the penetrance of the disease is 75%.Two individuals known to be heterozygotes have a child.What is the probability that the child exhibits the disease?

Accepted Answer

A) 1/4 
B) 3/4 
C) 1/8 
D) 3/16 
E) 9/16
The child will exhibit the phenotype only if its genotype is gg.And if its genotype is gg, a 75% penetrance means that there is only a 75% chance that the gg genotype will cause the child to exhibit the phenotype.The chance that two heterozygotes (Gg * Gg) have a gg child is 1/4.Multiplying this probability by 75% gives 1/4 * 3/4 = 3/16 
A) 1/4 
B) 3/4 
C) 1/8 
D) 3/16 
E) 9/16
The child will exhibit the phenotype only if its genotype is gg.And if its genotype is gg, a 75% penetrance means that there is only a 75% chance that the gg genotype will cause the child to exhibit the phenotype.The chance that two heterozygotes (Gg * Gg) have a gg child is 1/4.Multiplying this probability by 75% gives 1/4 * 3/4 = 3/16 D

Question 3

What would be an explanation for the phenomenon where a cross of a purebred, female, red eyed fruit fly with a purebred male, white eyed fly resulted in a phenotypic ratio that has a significantly greater number of red eyed flies than would be predicted by using Mendel's laws?

Accepted Answer

A) The red eye allele is dominant and sex linked. 
B) The white eye allele is dominant and sex linked 
C) The red eye allele is recessive and lethal 
D) The white eye allele is recesive and lethal 
E) male pattern baldness 
A) The red eye allele is dominant and sex linked. 
B) The white eye allele is dominant and sex linked 
C) The red eye allele is recessive and lethal 
D) The white eye allele is recesive and lethal 
E) male pattern baldness D

Question 4

Which of the following ratios demonstrate gene interaction?

Accepted Answer

A) 2:1 
B) 3:1 
C) 1:2:1 
D) 9:3:4 
E) 1:3 
A) 2:1 
B) 3:1 
C) 1:2:1 
D) 9:3:4 
E) 1:3

Question 5

The phenotypic ratio 9:7 may indicate

Accepted Answer

A) complete dominance. 
B) codominance. 
C) epistasis. 
D) recessive lethal. 
E) complementary gene action. 
A) complete dominance. 
B) codominance. 
C) epistasis. 
D) recessive lethal. 
E) complementary gene action.

Question 6

Predict the genotypes and phenotypes of the F1 progeny of a cross between a homozygous black rat and an albino homozygous for cream.

Accepted Answer

A) PPBB, black 
B) PpBb, black 
C) PpBb, albino 
D) ppBb, albino 
A) PPBB, black 
B) PpBb, black 
C) PpBb, albino 
D) ppBb, albino

Question 7

Predict the phenotypic ratio of the F2 progeny of a cross between two colorless plants, one homozygous for A and the other homozygous for B.

Accepted Answer

A) 3 colored : 1 colorless 
B) 9 colored : 7 colorless 
C) 9 colorless : 7 colored 
D) 15 colorless : 1 colored 
E) 15 colored : 1 colorless 
A) 3 colored : 1 colorless 
B) 9 colored : 7 colorless 
C) 9 colorless : 7 colored 
D) 15 colorless : 1 colored 
E) 15 colored : 1 colorless

Question 8

Which of the following phenotypic ratios show incomplete dominance?

Accepted Answer

A) 2:1 
B) 3:1 
C) 1:2:1 
D) 1:1 
E) 4:1 
A) 2:1 
B) 3:1 
C) 1:2:1 
D) 1:1 
E) 4:1

Question 9

Which of the following ratios show codominance?

Accepted Answer

A) 2:1 
B) 3:1 
C) 1:2:1 
D) 1:1 
E) 4:1 
A) 2:1 
B) 3:1 
C) 1:2:1 
D) 1:1 
E) 4:1

Question 10

Predict the genotypes and phenotypes of the F1 progeny of a cross between two colorless plants, one homozygous for A and the other homozygous for B.

Accepted Answer

A) AAbb, colorless 
B) aaBB, colorless 
C) AaBb, colored 
D) AaBb, colorless 
E) aabb, colored 
A) AAbb, colorless 
B) aaBB, colorless 
C) AaBb, colored 
D) AaBb, colorless 
E) aabb, colored

Question 11

The phenotypic ratio 9:3:4 may indicate

Accepted Answer

A) complete dominance. 
B) codominance. 
C) epistasis. 
D) recessive lethal. 
E) codominance and epistasis only. 
A) complete dominance. 
B) codominance. 
C) epistasis. 
D) recessive lethal. 
E) codominance and epistasis only.

Question 12

Which of the following is not a phenotypic description of allele interactions affecting the expression of traits?

Accepted Answer

A) incomplete dominance 
B) codominance 
C) polymorphic 
D) multifactorial 
E) pleiotrophic 
A) incomplete dominance 
B) codominance 
C) polymorphic 
D) multifactorial 
E) pleiotrophic

Question 13

The gene that controls ABO blood type phenotype demonstrate which of the following inheritance patterns?

Accepted Answer

A) complete dominance. 
B) recessiveness. 
C) codominance. 
D) complete dominance, recessiveness, and codominance 
E) none of the choices is correct. 
A) complete dominance. 
B) recessiveness. 
C) codominance. 
D) complete dominance, recessiveness, and codominance 
E) none of the choices is correct.

Question 14

In some plants, a purple pigment is synthesized from a colorless precursor.In a cross between two parental plants, one purple and the other colorless, an F1 generation was produced that was all purple.The F2 produced from the F1 had 775 purple, 200 red and 65 colorless plants.What mode of inheritance and phenotypic ratio do these results suggest?

Accepted Answer

A) Incomplete dominance, 1:2:1 phenotype ratio 
B) Dominant epistasis, 12:3:1 phenotype ratio 
C) Codominance, 1:2:1 phenotype ratio 
D) Recessive epistasis, 9:3:4 phenotype ratio 
A) Incomplete dominance, 1:2:1 phenotype ratio 
B) Dominant epistasis, 12:3:1 phenotype ratio 
C) Codominance, 1:2:1 phenotype ratio 
D) Recessive epistasis, 9:3:4 phenotype ratio

Question 15

Which of the following ratios indicates a lethal gene?

Accepted Answer

A) 2:1 
B) 3:1 
C) 1:2:1 
D) 1:1 
E) 4:1 
A) 2:1 
B) 3:1 
C) 1:2:1 
D) 1:1 
E) 4:1

Question 16

What can explain the phenomenon where the same genotype might give rise to different phenotypes?

Accepted Answer

A) pleiotropy 
B) codominance 
C) incomplete dominance 
D) complete dominance 
E) penetrance and expressivity 
A) pleiotropy 
B) codominance 
C) incomplete dominance 
D) complete dominance 
E) penetrance and expressivity

Question 17

A number of interacting genes produce quantitative inheritance.The transmission of these genes can be seen in the phenotypical pattern of

Accepted Answer

A) discontinuous distribution of discrete phenotypes. 
B) continuous variation in phenotypic expression. 
C) strict dominance and recessiveness. 
D) only discontinuous distribution of discrete phenotypes and continuous variation in phenotypic expression. 
A) discontinuous distribution of discrete phenotypes. 
B) continuous variation in phenotypic expression. 
C) strict dominance and recessiveness. 
D) only discontinuous distribution of discrete phenotypes and continuous variation in phenotypic expression.

Question 18

If a phenotype is controlled by the genotypes at two different loci the interaction of these genes is called

Accepted Answer

A) epistasis. 
B) epigenetics. 
C) dominance. 
D) codominance. 
E) incomplete dominance. 
A) epistasis. 
B) epigenetics. 
C) dominance. 
D) codominance. 
E) incomplete dominance.

Question 19

Which ratio would indicate that a phenotype is controlled by multiple genes?

Accepted Answer

A) 3:1 
B) 2:1 
C) 1:2:1 
D) 9:3:3:1. 
A) 3:1 
B) 2:1 
C) 1:2:1 
D) 9:3:3:1.

Question 20

If a gene is monomorphic in a population the most likely phenotypic ratio for the trait that would be obtained from a cross between two random individuals in the population would be

Accepted Answer

A) 2:1 
B) Cannot be predicted 
C) 1 
D) 3:1 
A) 2:1 
B) Cannot be predicted 
C) 1 
D) 3:1

The phenotypic ratio 2:1 may indicate

A certain disease is caused by homozygosity of the g allele (G is the corresponding wild-type allele).However, the penetrance of the disease is 75%.Two individuals known to be heterozygotes have a child.What is the probability that the child exhibits the disease?

What would be an explanation for the phenomenon where a cross of a purebred, female, red eyed fruit fly with a purebred male, white eyed fly resulted in a phenotypic ratio that has a significantly greater number of red eyed flies than would be predicted by using Mendel's laws?

Which of the following ratios demonstrate gene interaction?

The phenotypic ratio 9:7 may indicate

Predict the genotypes and phenotypes of the F₁ progeny of a cross between a homozygous black rat and an albino homozygous for cream.

Predict the phenotypic ratio of the F₂ progeny of a cross between two colorless plants, one homozygous for A and the other homozygous for B.

Which of the following phenotypic ratios show incomplete dominance?

Which of the following ratios show codominance?

Predict the genotypes and phenotypes of the F₁ progeny of a cross between two colorless plants, one homozygous for A and the other homozygous for B.

The phenotypic ratio 9:3:4 may indicate

Which of the following is not a phenotypic description of allele interactions affecting the expression of traits?

The gene that controls ABO blood type phenotype demonstrate which of the following inheritance patterns?

Which of the following ratios indicates a lethal gene?

What can explain the phenomenon where the same genotype might give rise to different phenotypes?

A number of interacting genes produce quantitative inheritance.The transmission of these genes can be seen in the phenotypical pattern of

If a phenotype is controlled by the genotypes at two different loci the interaction of these genes is called

Which ratio would indicate that a phenotype is controlled by multiple genes?

If a gene is monomorphic in a population the most likely phenotypic ratio for the trait that would be obtained from a cross between two random individuals in the population would be

Genetics: The Study of Biological Information

Mendels Principles of Heredity

The Chromosome Theory of Inheritance

Linkage, Recombination, and the Mapping of Genes on Chromosomes

DNA Structure, Replication, and Recombination

Anatomy and Function of a Gene: Dissection Through Mutation

Gene Expression: The Flow of Information From DNA to RNA to Protein

Digital Analysis of Genomes

Analyzing Genomic Information

The Eukaryotic Chromosome

Chromosomal Rearrangements and Changes in Chromosome Number

Bacterial Genetics

Organellar Inheritance

Gene Regulation in Prokaryotes

Gene Regulation in Eukaryotes

Manipulating the Genomes of Eukaryotes

The Genetic Analysis of Development

The Genetics of Cancer

Variation and Selection in Populations

Genetics of Complex Traits

Filters

Exam 3: Extensions to Mendels Laws

The phenotypic ratio 2:1 may indicate

A certain disease is caused by homozygosity of the g allele (G is the corresponding wild-type allele).However, the penetrance of the disease is 75%.Two individuals known to be heterozygotes have a child.What is the probability that the child exhibits the disease?

What would be an explanation for the phenomenon where a cross of a purebred, female, red eyed fruit fly with a purebred male, white eyed fly resulted in a phenotypic ratio that has a significantly greater number of red eyed flies than would be predicted by using Mendel's laws?

Which of the following ratios demonstrate gene interaction?

The phenotypic ratio 9:7 may indicate

Predict the genotypes and phenotypes of the F1 progeny of a cross between a homozygous black rat and an albino homozygous for cream.

Predict the phenotypic ratio of the F2 progeny of a cross between two colorless plants, one homozygous for A and the other homozygous for B.

Which of the following phenotypic ratios show incomplete dominance?

Which of the following ratios show codominance?

Predict the genotypes and phenotypes of the F1 progeny of a cross between two colorless plants, one homozygous for A and the other homozygous for B.

The phenotypic ratio 9:3:4 may indicate

Which of the following is not a phenotypic description of allele interactions affecting the expression of traits?

The gene that controls ABO blood type phenotype demonstrate which of the following inheritance patterns?

Which of the following ratios indicates a lethal gene?

What can explain the phenomenon where the same genotype might give rise to different phenotypes?

A number of interacting genes produce quantitative inheritance.The transmission of these genes can be seen in the phenotypical pattern of

If a phenotype is controlled by the genotypes at two different loci the interaction of these genes is called

Which ratio would indicate that a phenotype is controlled by multiple genes?

If a gene is monomorphic in a population the most likely phenotypic ratio for the trait that would be obtained from a cross between two random individuals in the population would be

Genetics: The Study of Biological Information

Mendels Principles of Heredity

The Chromosome Theory of Inheritance

Linkage, Recombination, and the Mapping of Genes on Chromosomes

DNA Structure, Replication, and Recombination

Anatomy and Function of a Gene: Dissection Through Mutation

Gene Expression: The Flow of Information From DNA to RNA to Protein

Digital Analysis of Genomes

Analyzing Genomic Information

The Eukaryotic Chromosome

Chromosomal Rearrangements and Changes in Chromosome Number

Bacterial Genetics

Organellar Inheritance

Gene Regulation in Prokaryotes

Gene Regulation in Eukaryotes

Manipulating the Genomes of Eukaryotes

The Genetic Analysis of Development

The Genetics of Cancer

Variation and Selection in Populations

Genetics of Complex Traits

Filters

Predict the genotypes and phenotypes of the F₁ progeny of a cross between a homozygous black rat and an albino homozygous for cream.

Predict the phenotypic ratio of the F₂ progeny of a cross between two colorless plants, one homozygous for A and the other homozygous for B.

Predict the genotypes and phenotypes of the F₁ progeny of a cross between two colorless plants, one homozygous for A and the other homozygous for B.