Exam 1 Online HW

The frequency of the melanistic allele is especially high in populations that live in areas with high frequency of canine distemper, a viral disease that frequently leads to death in dogs, wolves, and some other canid species. Heritable resistance to canine distemper is associated with pleiotropic effects of the CPD gene, (its encoded protein also has an immune function as part of the β-defensin protein family). Survival of melanistic wolves that carry at least one copy of the dominant allele is significantly higher during years with large outbreaks of the canine distemper virus. This suggests that an increase in the melanistic allele frequency of the CPD gene in years with canine distemper outbreaks likely occurs as a consequence of ______ on the _____ ______, and that changes in frequency of the phenotypic trait ______ are merely an incidental result of pleiotropy and likely not adaptive in their own right.

- Directional selection - phenotype - "canone distemper resistance" - "coat color"

In a particular recessive genetic disorder, you find the allele frequency for this recessive allele in a population is 0.02. Assuming the population is in Hardy-Weinberg Equilibrium over the last generation, which of the following are possible statements about this population?

- This genetic disorder could display severe and potentially fatal health complications only in individuals above 50 years of age. - Most of the recessive alleles are found in heterozygous individuals. - The population under investigation could have been formed by a founder event several hundred years ago.

You sampled 1000 individuals from a population of mosquitoes to test whether they are in Hardy-Weinberg Equilibrium for a gene D, where a recessive allele (d) is responsible for conferring pesticide resistance. After genotyping your 1000 sampled mosquitoes, you obtain the following number of individuals for the three possible genotypes: Genotype dd: 22 individuals Genotype Dd: 188 individuals Genotype DD: 790 individuals Assuming that this population of mosquitoes does NOT violate any Hardy-Weinberg assumptions in the next generation, what is the expected number of heterozygous individuals in this sample?

205

What genotype frequencies are expected under Hardy-Weinberg equilibrium for a population with allele frequencies of p = 0.81 and q = 0.19 for a particular gene?

AA = 0.656, Aa = 0.308 and aa = 0.036

Which of the following is a prediction of the Hardy-Weinberg principle?

Expected genotype frequencies can be determined from allele frequencies

According to the results in the previous question, you can conclude that the mosquito population evolved (or non-randomly mated). Over which generation must one or more assumptions of Hardy-Weinberg been violated?

From the previous generation to the current generation.

Whether baby sea horses develop orange or purple body color

IS NOT subject to natural selection

Whether baby sea horses have the ability to change their color depending on their environment

IS POTENTIALLY subject to natural selection

Use the information on allele frequencies in three populations to select the correct statement. Population A: p = 1 q = 0 Population B: p = 0.6 q = 0.4 Population C: p = 0 q = 1

Population B has more genetic diversity than does population C

Monkey flowers (Mimulus guttatus) living near the sites of copper mines can grow in soil containing high concentrations of copper, which is toxic to most plants. Copper tolerance is a heritable trait, and in several sites near old copper mines, the allele conferring copper tolerance has become fixed. Which statement is correct?

Prior to mining, the population contained both copper-tolerant and copper-intolerant plants

The Hardy-Weinberg equation is p2 + 2pq + q2 = 1. What does the fact that the genotype frequencies add up to 1 demonstrate?

That the frequencies of each genotype have been determined correctly

In a woodland, 50% of larkspur flower (Corydalis cava) individuals have purple flowers and 50% have white flowers. Flower color is determined by a single gene with two alleles. Homozygous dominant and heterozygous individuals have purple flowers, homozygous recessive individuals have white flowers. In a hypothetical scenario, a rabbit family that eats just purple flowers moves into the woodland. When a rabbit finds a purple-flowered plant, it eats all the flowers on that plant. Although the plant survives having its flowers eaten, it produces no seeds. After many generations, ....

The allele frequency for the "white" allele is likely to become fixed.

Why does natural selection prevent a population from remaining in Hardy-Weinberg equilibrium?

certain alleles increase because they increase reproductive success

Which of the following best defines biological evolution within a population?

change in allele frequencies over time

Sequencing of the dominant allele of the CPD gene in melanistic wolves revealed that the allele is identical to one found in domesticated dog populations and likely originated there and subsequently entered the North American wolf population as a result of ______, which was estimated to have occurred once sometime between 1500 and 6000 years ago with Native American domesticated dogs.

gene flow between grey wolves and domesticated dogs

The frequency of the heterozygous genotype is higher in modern grey wolf populations in the US than would be expected if the wolf population were in Hardy-Weinberg Equilibrium for gene CPD, consistent with _____ for coat color in these wolf populations.

negative assortative mating

A particular recessive genetic disorder is fatal before birth, so there are no homozygous recessive individuals. In a particular population, one in 15 individuals is a carrier for this disorder. What are the allele frequencies of the dominant (p) and recessive (q) alleles in this population?

p = 0.967, q = 0.033

Use the Hardy-Winberg principle to test whether this population is evolving. To do so, calculate the allele frequencies in the sample, use these to predict expected numbers of individuals for each genotype, if the null-hypothesis is true, and this population is NOT evolving, then use a Chi-Square test to determine the p-value for this null-hypothesis to support your conclusion.

p<0.05; conclude that population is not in Hardy-Weinberg