Q: Which formula is used to calculate Tajima’s D, a statistic for detecting genetic bottlenecks?

$$D = \frac{\text{mean pairwise differences} - \text{number of segregating sites}}{\text{scaled variance}}$$

Question 1

In an inbred population that otherwise obeys Hardy-Weinberg equilibrium (HWE) assumptions, what is the formula for the frequency of heterozygotes ($$A_{12}) $$given inbreeding coefficient $$F$$?

Accepted Answer

$$2pq(1-F)$$

Question 2

Which evolutionary force is assumed to be the most important in generating isolation by distance (IBD) patterns in populations?

Accepted Answer

Genetic drift

Question 3

A study of lungless salamanders shows a strong correlation between pairwise genetic distance and geographic distance. What does this pattern most likely indicate?

Accepted Answer

Isolation by distance

Question 4

What is the primary force assumed to lead to isolation by environment (IBE) in populations?

Accepted Answer

Natural selection

Question 5

Which statistical method combines geographic distances and historical suitability estimates to provide a better regression model for genetic structure?

Accepted Answer

MMRR (Multiple Matrix Regression with Randomization)

Question 6

What is a genetic bottleneck and how does it affect genetic variation in a population?

Accepted Answer

A sharp reduction in population size that decreases genetic diversity

Question 7

Which formula is used to calculate Tajima’s D, a statistic for detecting genetic bottlenecks?

Accepted Answer

$$D = \frac{	ext{mean pairwise differences} - 	ext{number of segregating sites}}{	ext{scaled variance}}$$

Question 8

A population of Greater Prairie Chickens in Wisconsin experienced a bottleneck. What was the observed effect on genetic variation?

Accepted Answer

Decrease in heterozygosity and number of alleles per locus

Question 9

Which method allows inference of population demographic change based on sequence variation and genealogy, as developed by Drummond et al. (2005)?

Accepted Answer

Bayesian skyline plot

Question 10

What is the difference between the fundamental niche and the realized niche of a species?

Accepted Answer

The fundamental niche is the set of resources and conditions necessary for viability, while the realized niche is the portion actually occupied

Question 11

Which hypothesis explains higher species richness in the tropics due to climatic stability?

Accepted Answer

Climatic Stability hypothesis

Question 12

If a population has a high value of Tajima’s D, what does this suggest about its demographic history?

Accepted Answer

Population contraction or balancing selection

Question 13

Which equation describes the expected frequency of heterozygotes under Hardy-Weinberg equilibrium with inbreeding coefficient $$F$$?

Accepted Answer

$$2pq(1-F)$$

Question 14

What is the main assumption behind the use of georeferenced locality data and environmental layers in estimating a species’ potential geographic distribution?

Accepted Answer

Species presence/absence and environmental variables together define the niche envelope

Question 15

Which of the following is NOT a plausible consequence of a genetic bottleneck?

Accepted Answer

Increased genetic diversity

Question 16

What does a high $$r^2$$ value in a regression of genetic distance versus geographic distance indicate about a population?

Accepted Answer

Strong isolation by distance

Question 17

Which of the following is a real-world application of climate data in biodiversity studies?

Accepted Answer

Estimating the environmental requirements and potential geographic distribution of a species

Question 18

Which equation is used to calculate nucleotide diversity ($$\pi) $$for a population?

Accepted Answer

$$\pi = \frac{\sum_{i\u003cj} d_{ij}}{\binom{n}{2}}$$

Question 19

Which of the following is a plausible explanation for higher intraspecific genetic diversity in tropical regions?

Accepted Answer

Higher productivity and more complex biotic interactions

Question 20

If a population shows a frequency distribution of pairwise differences with a peak at low values, what does this suggest about its demographic history?

Accepted Answer

Recent population expansion

lec 25

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