Q: Which formula is used to calculate the map distance between two genes using recombination frequency?

$$d = 100 \times \frac{\text{number of recombinant offspring}}{\text{total number of offspring}}$$

Q: A population of 1000 individuals has 360 AA, 480 Aa, and 160 aa genotypes. What is the frequency of allele a?

$$q = \frac{2 \times 160 + 480}{2 \times 1000} = 0.4$$

Question 1

A researcher observes a dihybrid cross in peas and finds a 9:7 phenotypic ratio in the F2 generation. Which type of gene interaction most likely explains this result?

Accepted Answer

Epistasis involving two genes in the same pathway

Question 2

Which of the following best describes how biochemical pathways can be inferred from gene interaction studies?

Accepted Answer

By analyzing epistatic relationships, the order of gene function in a pathway can be deduced

Question 3

In a pedigree, a trait appears only when both parents are unaffected but carry the allele. What is the most likely mode of inheritance?

Accepted Answer

Autosomal recessive

Question 4

Which formula is used to calculate the map distance between two genes using recombination frequency?

Accepted Answer

$$d = 100 	imes \frac{	ext{number of recombinant offspring}}{	ext{total number of offspring}}$$

Question 5

During meiosis, crossing over between homologous chromosomes results in which of the following genetic outcomes?

Accepted Answer

Increased genetic diversity due to new allele combinations

Question 6

A geneticist uses a three-point test cross to map three genes. If the double crossover class is the least frequent, what does this indicate?

Accepted Answer

Double crossovers are rare events and help determine gene order

Question 7

Which equation represents the Hardy-Weinberg equilibrium for a gene with two alleles, A and a, with frequencies $$p$$ and $$q$$?

Accepted Answer

$$p^2 + 2pq$$ + $$q^2 = 1$

Question 8

If a population is not in Hardy-Weinberg equilibrium, which of the following could be a possible cause?

Accepted Answer

Non-random mating

Question 9

A child is born with a rare genetic disorder. Both parents are healthy but have a family history of the disorder. What is the most likely explanation?

Accepted Answer

The disorder is autosomal recessive and both parents are carriers

Question 10

Which of the following best describes the effect of a selective sweep on genetic variation in a population?

Accepted Answer

It reduces genetic variation near the beneficial allele

Question 11

In a bacterial conjugation experiment, the time at which different genes are transferred is used to map their order on the chromosome. What is this technique called?

Accepted Answer

Interrupted mating

Question 12

Which of the following is a key difference between bacterial and eukaryotic genetics?

Accepted Answer

Bacteria can exchange genes via horizontal gene transfer

Question 13

A mutation changes a single base in a gene, resulting in a different amino acid in the protein. What type of mutation is this?

Accepted Answer

Missense mutation

Question 14

Which process involves the uptake of naked DNA by a bacterial cell from its environment?

Accepted Answer

Transformation

Question 15

A population of 1000 individuals has 360 AA, 480 Aa, and 160 aa genotypes. What is the frequency of allele a?

Accepted Answer

$$q = \frac{2 	imes 160 + 480}{2 	imes 1000} = 0.4$$

Question 16

Which of the following best explains why mitochondrial inheritance is only maternal?

Accepted Answer

Eggs contribute the majority of cytoplasm, including mitochondria, to the zygote

Question 17

Which of the following is a function of bacterial plasmids?

Accepted Answer

Carrying genes for antibiotic resistance

Question 18

In a population, the selection coefficient $$s$$ for a deleterious allele is 0.1. What does this mean?

Accepted Answer

Individuals with the allele have 10% lower fitness than those without it

Question 19

Which of the following best describes the principle of Bayesian analysis in genetics?

Accepted Answer

It updates the probability of a hypothesis as more data become available

Question 20

A patient is found to have a genetic disease caused by a mutation in a single gene. Genetic testing of the family reveals the mutation is present in the mother but not the father. The disease is present in both sons and daughters. What is the most likely mode of inheritance?

Accepted Answer

Autosomal dominant

Genetics Exam II Study Guide: Key Concepts and Applications

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