Gene Frequency and Selection Concepts

The video tutorial covers the Hardy-Weinberg law of genetic equilibrium, explaining how gene and genotype frequencies remain constant in large, random-mating populations without selection, migration, or mutation. It discusses how selection, a differential reproduction process, affects these frequencies. The concept of the coefficient of selection is introduced, with examples showing its application against undesirable genotypes. The tutorial provides a detailed example of selection against a homozygous recessive genotype and explains how to calculate changes in gene frequency using specific formulas. An exercise is provided to apply these concepts.

What does the Hardy-Weinberg law of genetic equilibrium state about gene frequencies in a large, random mating population?

• They increase over time regardless of external factors.

• They remain constant in the absence of selection, migration, and mutation.

• They decrease due to natural selection.

• They fluctuate randomly with no pattern.

How does selection affect gene and genotype frequencies in a population?

• It changes them by allowing only certain individuals to reproduce.

• It increases the frequency of all genotypes equally.

• It causes them to remain constant.

• It has no effect on them.

What is the coefficient of selection represented by?

• A lowercase s

• A capital S

• A number between 0 and 1

• A Greek letter

In the context of selection, what does a coefficient of selection of 1 indicate?

• The genotype frequency remains unchanged.

• No individuals of a genotype are allowed to breed.

• All individuals of a genotype are allowed to breed.

• 50% of individuals of a genotype are allowed to breed.

What happens to the genotype frequency of homozygous dominant individuals after selection?

• It decreases to zero.

• It remains the same as before selection.

• It increases to twice its original value.

• It becomes half of its original value.

How is the frequency of a recessive gene after selection calculated?

• By dividing the initial frequency by the coefficient of selection.

• By multiplying the initial frequency by the coefficient of selection.

• By adding the gametic contributions of homozygous recessive and heterozygous genotypes.

• By subtracting the coefficient of selection from the initial frequency.

What is the formula for calculating the change in gene frequency per generation due to selection?

• Delta Q = Q1 / Q

• Delta Q = Q1 - Q

• Delta Q = Q1 * Q

• Delta Q = Q1 + Q

Which factors influence the effect of selection on gene frequency?

• The coefficient of selection and the initial frequency of the recessive allele.

• The size of the population and the mutation rate.

• The initial frequency of the dominant allele and the mutation rate.

• The migration rate and the mutation rate.

In the given exercise, what is the initial frequency of the recessive gene?

• 0.1

• 0.2

• 0.3

• 0.4

What is the coefficient of selection against the homozygous recessive genotype in the exercise?

• 0.1

• 0.4

• 0.2

• 0.3