Exam 18: Population Genetics

Suppose that a population of 25 black-footed ferrets has an initial heterozygosity (H)of 0.5.How many generations will it take for this population to decline to a heterozygosity of 0.25?

You identify a population of mice (Peromyscus maniculatus)on an island.Their coat color is controlled by a single gene: BB mice are black,Bb mice are gray,and bb mice are white.You take a census of the population and record the following numbers of mice. Black 200 Gray 160 White 40 a)What are the frequencies of the two alleles? b)What are the Hardy-Weinberg equilibrium frequencies for these three phenotypes? c)A heat wave hits the island.All 200 mice with black fur die from heat stroke,but the other mice survive.What are the new allele frequencies for the population? d)If the population suffers no further cataclysms after the heat wave,and the surviving animals mate randomly,what will be the frequency of mice with black fur in the next generation?

The genetic frequencies of two separate populations are: AA Aa aa Population 1 .36 .48 .16 Population 2 .33 .33 .33 Popllation 3 .55 .10 .35 Which of these populations are in Hardy-Weinberg equilibrium?

Some forms of cleft palate are caused by recessive alleles of a gene on the X chromosome.In an Icelandic population,3.6 * 10^-3 of the females have this form of cleft palate.What proportion of the males would you expect to be affected,assuming Hardy-Weinberg equilibrium?

How is the genetic composition of a population defined?

Two chromosomes having the same combination of alleles at multiple loci are said to be of similar:

In a Pygmy group in central Africa,the frequencies of alleles determining the ABO blood groups were estimated as 0.2 for I^A,0.1 for I^B,and 0.7 for i.Assuming random mating with respect to blood group,determine the expected frequencies of the blood types A,B,AB,and O.

Suppose that a population of 100 black-footed ferrets has an initial heterozygosity (H)of 0.5.How many generations will it take for this population to decline to a heterozygosity of 0.25?

Tay-Sachs disease is inherited as an autosomal recessive.In a certain large eastern European population,the frequency of Tay-Sachs disease is 1 percent. a)If the population is assumed to be in Hardy-Weinberg equilibrium with respect to Tay-Sachs,what is the frequency of the allele that causes Tay-Sachs? b)What would be the frequency of heterozygotes? c)What is the probability of two heterozygotes marrying? d)In children of such marriages,what would be the frequency of Tay-Sachs disease? e)What proportion of all Tay-Sachs births are produced by such marriages?

Apert syndrome (acrocephalosyndactyly)results from a dominant mutant allele.Among 322,182 births to normal parents,two infants were found with this syndrome.What is the mutation rate per gamete for this genetic disease?

Suppose that you are a genetic counselor,and a couple seeks your advice about BHT tasting (people who can taste BHT in processed food are recessive homozygotes for the "taster" allele and nontasters are homozygous dominant or heterozygous for the "nontaster" allele).Both prospective parents are nontasters,but a careful analysis of the husband's pedigree reveals that he is a carrier of the taster allele.The two alleles are in Hardy-Weinberg equilibrium,and the proportion of BHT tasters in the population is 16 percent.What is the probability that the couple's first child will be a nontaster of BHT?

Which of the following is a question that population genetics would address?

The MN blood group in humans is under the control of a pair of codominant alleles,L^M and L^N.In a group of 556 individuals,the following genotypic frequencies are found: 167 MM 280 MN 109 NN a)Calculate the frequency of the L^M and L^N alleles. b)Test (using the chi-squared test)whether the genotypic frequencies conform to the Hardy-Weinberg distribution.

In a human population,the genotype frequencies at one locus are 0.5 AA,0.4 Aa,and 0.1 aa.The frequency of the A allele is:

A gene or a trait is said to be polymorphic if:

You identify a population of mice (Peromyscus maniculatus)on an island.Their coat color is controlled by a single gene: BB mice are black,Bb mice are gray,and bb mice are white.You take a census of the population and record the following numbers of mice: Black 200 Gray 160 White 40 As a consequence of human activity,the climate on the island is changed permanently.All 200 mice with black fur die from heat stroke,but the other mice survive.If the climate change causes mice with black fur to die before reproducing,which of the following statements are correct?

In a population,the D →d mutation rate is 4 *10^-6.If p = 0.8 today,what will p be after 50,000 generations?

What group of organisms has,overall,the highest genetic diversity?

In a tropical human population in Hardy-Weinberg equilibrium for an autosomal locus determining presence/absence of pigment in the skin,the frequency of albinism (aa)is 1 in 10,000.The frequency of heterozygotes is approximately:

What processes increase genetic variation in a given population?