Q: Which equation correctly represents the calculation of allele frequency for allele 'a' in a population where there are $$AA$$, $$Aa$$, and $$aa$$ genotypes?

$$f(a) = \frac{2 \times \text{number of } aa + \text{number of } Aa}{2 \times \text{total individuals}}$$

Question 1

Which of the following best explains why the number of genes in eukaryotic genomes does NOT correlate with organismal complexity?

Accepted Answer

Eukaryotic genomes contain a high proportion of non-coding and repetitive DNA, which increases genome size without increasing gene number.

Question 2

A mutation occurs in a gene that does not affect the fitness of an organism. Over time, what is the most likely fate of this mutation in a large population?

Accepted Answer

Its frequency will change slowly and randomly due to genetic drift.

Question 3

Which equation correctly represents the calculation of allele frequency for allele 'a' in a population where there are $$AA$$, $$Aa$$, and $$aa$$ genotypes?

Accepted Answer

$$f(a) = \frac{2 	imes 	ext{number of } aa + 	ext{number of } Aa}{2 	imes 	ext{total individuals}}$$

Question 4

Which of the following is a key difference between prokaryotic and eukaryotic genomes?

Accepted Answer

Prokaryotic genomes are colinear, while eukaryotic genomes are interrupted by introns.

Question 5

Gene duplication can lead to the formation of gene families. Which process is most likely responsible for the divergence of function among family members?

Accepted Answer

Accumulation of mutations in duplicated genes over time.

Question 6

In a population of 10 individuals, there are 6 chromosomes with allele 'a' and 14 with allele 'A'. What is the frequency of allele 'a'?

Accepted Answer

$$f(a) = \frac{6}{20} = 0.3$$

Question 7

Which of the following statements about genetic drift is TRUE?

Accepted Answer

Genetic drift has a greater effect in small populations, leading to faster fixation or loss of alleles.

Question 8

Which of the following best describes a selectively neutral mutation?

Accepted Answer

A mutation that does not affect the fitness of an organism and whose frequency changes mainly by genetic drift.

Question 9

Which of the following is NOT a mechanism by which complex organisms can gain new genes?

Accepted Answer

Loss of all non-essential genes.

Question 10

Which of the following is TRUE regarding the relationship between genome size and gene number in prokaryotes?

Accepted Answer

There is a linear relationship; most of the genome codes for genes.

Question 11

Which of the following best explains why most disease-associated alleles are recessive?

Accepted Answer

Recessive alleles are only selected against in homozygous individuals, allowing them to persist in heterozygotes.

Question 12

Which of the following is a characteristic of highly repetitive DNA?

Accepted Answer

It consists of very short sequences (less than 100 bp) repeated thousands of times.

Question 13

A gene family is defined as:

Accepted Answer

A group of genes that evolved from the same ancestral gene and share sequence homology.

Question 14

Which of the following best describes the fate of a duplicated gene copy over evolutionary time?

Accepted Answer

It may acquire mutations and diverge in function, become a pseudogene, or retain the original function.

Question 15

Which of the following is an example of a paralogous gene relationship?

Accepted Answer

Hemoglobin alpha and beta genes within the same species.

Question 16

Which of the following equations best describes the expected genotype frequencies under Hardy-Weinberg equilibrium for alleles $$A$$ and $$a$$ with frequencies $$p$$ and $$q$$?

Accepted Answer

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

Question 17

Which of the following is TRUE about the effect of population size on genetic drift?

Accepted Answer

Genetic drift causes allele frequencies to change more rapidly in small populations.

Question 18

Which of the following statements about gene clusters is correct?

Accepted Answer

Gene clusters can contain both functional genes and pseudogenes, often arising from gene duplication events.

Question 19

Which of the following best describes the difference between orthologs and paralogs?

Accepted Answer

Orthologs are genes in different species that evolved from a common ancestral gene, while paralogs are genes within the same species that arose by duplication.

Genome Evolution: Structure, Variation, and Mechanisms

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