Question 39 of 50

What is the term for a gene that masks or overpowers the effect of another gene in a genetic interaction?

In the classic example of coat color in Labrador retrievers, the 'ee' genotype results in a yellow coat regardless of the alleles at the B locus. What is the resulting phenotypic ratio of a dihybrid cross (BbEe x BbEe)?

A trait is controlled by multiple genes acting cumulatively, resulting in a measurable phenotype like height or skin color that varies continuously. What is the term for these genes?

In a complementation test, two true-breeding individuals with the same recessive mutant phenotype are crossed. If the F1 offspring all display the wild-type phenotype, what does this indicate?

According to the formula provided for quantitative traits with incomplete dominance, how many discrete phenotypes can be produced if a trait is controlled by three cumulative effect QTLs?

What is the expected phenotypic ratio for a dihybrid cross that demonstrates complementary gene interaction?

In the context of dog coat genetics, which gene is identified as corresponding to the B locus, controlling black versus brown pigment production?

In barley, a cross between two different true-breeding strains with short awns produces F1 offspring with long awns. What is the expected phenotypic ratio in the F2 generation from a self-cross of the F1 individuals?

In wheat, two genes control red versus white pigmentation. The presence of at least one dominant allele at either locus is sufficient to produce red pigment. What is the term for this type of gene interaction?

In a complementation test involving six true-breeding mutant strains, strains 1, 5, and 6 fail to complement each other but complement strains 2, 3, and 4. What do strains 1, 5, and 6 constitute?

The protein melanophilin, encoded by the D locus in dogs, is responsible for the transport of melanosomes. A recessive allele (d) leads to fewer transported melanosomes. This results in what phenotype?

In a complementation test between two mutant flower strains, one white and one blue, the F1 offspring are all blue. What can be concluded from this result?

Which pigment is responsible for the reddish-gold colors in mammals, and is predominantly produced in dogs with the 'ee' genotype?

Fanconi anemia is a human disorder with 22 known complementation groups, such as FancA, FancB, etc. What does this large number of complementation groups imply about the genetic basis of the disorder?

What type of trait is characterized by continuous variation and is controlled by multiple genes acting cumulatively?

In a dihybrid cross where the dominant alleles of both genes yield the same phenotype, resulting in a 15:1 ratio, what is this form of epistasis called?

What is the primary function of the product of the MITF gene (S locus) in dogs?

A dihybrid cross gives an expected offspring ratio of 9 black (and undilute) : 3 silver (black and dilute) : 3 brown (and undilute) : 1 silvery brown. What does this 9:3:3:1 ratio indicate about the interaction between the two genes involved?

In the biochemical pathway for purple pigment production (colorless precursor -> colorless intermediate -> purple pigment), gene A controls the first step and gene B controls the second. A mutation in which gene(s) would result in a white (colorless) phenotype?

What type of variation is characterized by easily distinguishable categories, such as round vs. wrinkled seeds in Mendel's peas?

The gene for curly fur (Cu) in dogs is incompletely dominant to smooth fur (CuC). The gene for short fur (L) is dominant to long fur (l). However, a dog with a short coat is likely to have straight fur, regardless of its genotype at the Cu locus. What term best describes this gene interaction?

In a dihybrid cross for a trait controlled by two genes with a cumulative effect (like barley awns), what is the genotype of an individual with the intermediate (short awn) phenotype?

Why is it possible to determine the B-locus genotype of a yellow Labrador retriever by looking at its nose?

What is the primary limitation of a standard complementation test?

For quantitative traits, what is typically the most common phenotype in a population?

What type of gene interaction is occurring if a dihybrid cross results in a 12:3:1 phenotypic ratio?

In a hypothetical complementation test with four mutant strains, the results show that strain 2 crossed with strain 3 produces mutant offspring, while all other pairwise crosses between different strains produce wild-type offspring. How many complementation groups are there?

The gene FGF5 is known to control which trait in both dogs and humans?

Specialized pigment-producing cells that synthesize melanin in organelles called melanosomes are known as what?

In human biology, a modified complementation test can be performed on cultured cells from Fanconi anemia patients. If fused cells from a patient and a known FancA cell line survive treatment with a DNA crosslinking agent, what can be concluded?

What is the term for a group of alleles of a single gene that contributes to a complex, multigenic phenotype, identified through a complementation test?

If a trait is controlled by five cumulative effect QTLs with incomplete dominance, how many discrete phenotypes can be produced?

What is the genetic basis for the wide phenotypic variation seen in dogs, such as the difference between a Great Dane and a Chihuahua?

In a dihybrid cross where the recessive 'e' allele is epistatic to the 'B' locus, what genotype would a brown Labrador retriever have?

When two genes work together additively to perform a duplicate function, such that a dominant allele at either gene gives a partial phenotype and dominant alleles at both give a full phenotype, this interaction is called what?

If a trait controlled by quantitative trait loci (QTLs) has 13 discrete phenotypes, how many loci are controlling the trait, assuming incomplete dominance?

The cellular mechanisms of what human genetic disorder are used as an example of how complementation tests can be adapted for clinical diagnostics?

As the number of phenotypic classes for a quantitative trait increases due to more contributing loci, what happens to the differences between the classes?

The gene MC1R, which corresponds to the E locus in dogs, has variations in humans that are associated with what trait?

In the context of the gene interactions in Table 2, what ratio represents 'No Interaction' in a dihybrid cross?

If two chickens with walnut combs are crossed and produce offspring in an approximate ratio of 9 walnut : 3 pea : 3 rose : 1 single, what can be inferred about the parental genotypes?

What is the key difference between how a dominant allele at one gene and dominant alleles at two genes affect the phenotype in a system with duplicate gene interaction with cumulative effect?

A quantitative trait is controlled by a single gene with two alleles.

How many phenotypic classes are produced in a dihybrid cross exhibiting recessive epistasis, like the Labrador coat color example?

The gene KRT71 in dogs is responsible for curly versus smooth fur. This is an example of a gene affecting what aspect of coat appearance?

In a case of dominant epistasis resulting in a 12:3:1 ratio, which genotypic classes are combined into a single phenotype?

A key finding in the study of multigenic inheritance in dogs is that centuries of inbreeding have created breeds that are genetically very what?

In the Fanconi anemia cellular complementation test, what is the role of the DNA crosslinking agent?

The interaction of the B and D loci in dog coat color, which produces four distinct phenotypes (black, brown, silver, silvery-brown) in a 9:3:3:1 ratio, is an example of what?