Genetics: From Genes to Genomes
6th Edition
ISBN: 9781259700903
Author: Leland Hartwell Dr., Michael L. Goldberg Professor Dr., Janice Fischer, Leroy Hood Dr.
Publisher: McGraw-Hill Education
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Chapter 21, Problem 14P
The equation p2 + 2pq + q2> = 1 representing the Hardy-Weinberg proportions examines genes with only two alleles in a population.
| a. | Derive a similar equation describing the equilibrium proportions of genotypes for a gene with three alleles. [Hint: Remember that the Hardy-Weinberg equation can be written as the binomial expansion (p + q)2 .] |
| b. | A single gene with three alleles (IA, IB, and i) is responsible for the ABO blood groups. Individuals with blood type A can be either IA IA or IA i; those with blood type B can be either IB IB or IB i; people with AB blood are IA IB, and type O individuals are ii. Among Armenians, the frequency of IA is 0.360, the frequency of IB is 0.104, and the frequency of i is 0.536. Calculate the frequencies of individuals in this population with the four possible blood types, assuming Hardy-Weinberg equilibrium. |
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In a human population, the following data were obtained for numbers of people with each blood type (for 3 alleles, use 3 variables p,q, and r ; Hardy-Weinburg equation becomes (p^2 + q^2 + r^2 +2pq + 2pr + 2qr = 1):Type O – 804Type A – 997Type B – 295Type AB – 177Is this population in Hardy-Weinberg equilibrium? Explain.
A sample of 100 individuals from a population that is dimorphic at the A locus has genotype counts as follows.
AA: 30
Aa: 60
aa: 10
a) What are the allele frequencies in the population?
b) What are the expected genotype frequencies, if the population were at HardyWeinberg equilibrium?
c) Is the proportion of heterozygotes lower or higher than expected at Hardy-Weinberg equilibrium? What deviations from the assumptions of the model would best explain the observed difference?
The equation p2+ 2pq + q2= 1 representing theHardy-Weinberg proportions examines genes withonly two alleles in a population.a. Derive a similar equation describing the equilibrium proportions of genotypes for a gene withthree alleles. [Hint: Remember that the HardyWeinberg equation can be written as the binomialexpansion (p + q)2.]b. A single gene with three alleles (IA, IB, and i) isresponsible for the ABO blood groups. Individualswith blood type A can be either IA IAor IA i;those with blood type B can be either IB IBor IB i;people with AB blood are IA IB, and type O individuals are ii. Among Armenians, the frequency of IAis0.360, the frequency of IBis 0.104, and the frequencyof i is 0.536. Calculate the frequencies of individuals in this population with the four possible bloodtypes, assuming Hardy-Weinberg equilibrium.In Problems 15–17, you will see that because matingbetween individuals within populations at Hardy-Weinbergequilibrium is random, it is possible to predict…
Chapter 21 Solutions
Genetics: From Genes to Genomes
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