HW #2 Questions - Genetic Variation & Hardy-Weinberg Equilibrium

What is the frequency of the A1A2 genotype in a population composed of 20 A1A1 individuals, 80 A1A2 individuals, and 100 A2A2 individuals?

0.4 The calculation to determine the frequency of the A1A2 genotype is: 80 A1A2 individuals / (20 + 80 + 100) total individuals = 0.4, the frequency of the A1A2 genotype.

A scientist samples a population of butterflies and finds that 56% are heterozygous at a particular locus. If the population is in Hardy-Weinberg equilibrium, what should be the frequency of the homozygous individuals in this population?

0.44

Which of the following are basic components of the Hardy-Weinberg model?

Frequencies of two alleles in a gene pool before and after many random matings

Which of the following statements about genetic variation is accurate?

Genetic variation must be present in a population before natural selection can act upon the population.

True or false? The Hardy-Weinberg model makes the following assumptions: no selection at the gene in question; no genetic drift; no gene flow; no mutation; random mating.

True - These are the 5 assumptions

According to the Hardy-Weinberg theorem, the frequencies of alleles in a population will remain constant if __________ is the only process acting on the gene pool.

random mating

The value of the Hardy-Weinberg equation is that it allows scientists to perform which of the following assessments?

to detect whether an evolutionary force is acting on a population

What is the frequency of the A1 allele in a population composed of 20 A1A1 individuals, 80 A1A2 individuals, and 100 A2A2 individuals?

A1 = 0.3 The frequency of the A1 allele is p = (number of A1 alleles) / (total of all alleles) = [(2 ( 20) + 80] / [(2 × 20) + (2 × 80) + (2 × 100)] = 0.3.

Which of the following statements is accurate with regard to a population in Hardy-Weinberg equilibrium?

Allele frequencies should not change from one generation to the next.

How does diploidy help to preserve genetic variation? See Concept 23.4

It allows recessive alleles that may not be favored in the current environment to be preserved in the gene pool by propagation in heterozygotes. Natural selection tends to decrease genetic variation. Recessive alleles are shielded from natural selection in heterozygotes.

Which of the following evolutionary forces could create new genetic information in a population?

Mutation(Why: mutations, which are changes in a cell's DNA, can introduce new genetic information in a population.)

Which of the following evolutionary forces consistently results in adaptive changes in allele frequencies?

Selection is the only evolutionary force that consistently results in adaptation. Mutation without selection and genetic drift are random processes that may lead to adaptive, maladaptive, or neutral effects on populations.

What genotype frequencies are expected under Hardy-Weinberg equilibrium for a population with allele frequencies of p = 0.8 and q = 0.2 for a particular gene?

The expected genotype frequencies are 0.64, 0.32, and 0.04 for A1A1, A1A2, and A2A2, respectively.(Why: the expected frequency of the A1A1 genotype is p^2=(0.8)(0.8)=0.64; the expected frequency of the A1A2 genotype is 2pq=2(0.8)(0.2)=0.32; the expected frequency of the A2A2 genotype is q^2=(0.2)(0.2)=0.4. To verify your calculations, confirm that the three frequencies add up to one.

Which of the following statements is not a part of the Hardy-Weinberg principle?

The genotype frequencies in the offspring generation must add up to two.

The effect of which Hardy-Weinberg condition is affected by population size?

genetic drift