Concept explainers
To analyze:
On the basis of the given data of two codominant alleles of five human population:
A. The allele frequencies of 5 populations.
B. Identify populations included in Hardy-Weinberg equilibrium.
C. The populations that experienced significant intermixing because of migration.
Introduction:
Explanation of Solution
The data obtained from 5 human populations are as follows:
Population | Place | MM | MN | NN |
Inuit | East Greenland | 83.5 | 15.6 | 0.9 |
Navajo Indians | New Mexico | 84.5 | 14.4 | 1.1 |
Finns | Karajala | 45.7 | 43.1 | 11.2 |
Russians | Moscow | 39.9 | 44.0 | 16.1 |
Aborigines | Queensland | 2.4 | 30.4 | 67.2 |
The Hardy-Weinberg equation helps to calculate and determine genotype frequencies in large populations that meet the requirements of equilibrium. The equation of Hardy-Weinberg is:
For a gene with two possible alleles, the allelic frequency is represented by p and q. In this case, p is the M allele and q is the N allele. For the MM and NN genotypes, every individual has two identical alleles, so the allelic frequency for those members can just be carried over from the genotype frequencies. For the MN genotype, half the alleles will be M and half will be N, so it needs to be split in half for each allele and then added to the frequencies from MM and NN individuals. It can be represented as:
A. Here, in the question, there are five populations. The allele frequencies in five populations are as follows:
Population: Inuit
Place:East Greenland
Population: Navajo Indians
Place: New Mexico
Population: Finns
Place: Karajala
Population: Russians
Place: Moscow
Population: Aborigines
Place: Queensland
B. For the given circumstances in the question, a gene exists as two alleles: M and N. To determine if the given populations are in equilibrium, the Hardy-Weinberg equation can be used to calculate the number of individuals with each genotype.
Inuit:
Navajo Indians:
Finns:
Russians:
Aborigines:
In general, these values agree pretty well with the equilibrium. Thus, it can be said that all five populations are in Hardy-Weinberg equilibrium.
C. Hardy-Weinberg equilibrium is affected by several factors, which include genetic isolation, mutation, natural selection, and non-random mating. Migration or gene flow is also one of the factors that affect the Hardy-Weinberg equilibrium. It usually causes changes in the allele frequency and hence results in subtle deviations from the Hardy-Weinberg equilibrium. Based on similar allele frequencies, the Inuit and Navajo Indians appear to have interbred as well as the Finns and Russians.
Therefore, it can be concluded that,
A. The allelic frequencies of the five populations are:
Inuit: p = 0.913, q = 0.087
Navajo Indians: p = 0.917, q = 0.083
Finns: p = 0.6725, q = 0.3275
Russians: p = 0.619, q = 0.383
Aborigines: p = 0.176, q = 0.824
B. All the five populations are in Hardy-Weinberg equilibrium.
C. Inuit and Navajo Indian populations may have interbred, as well the Finns and Russians, due to the similarities in their allelic frequencies.
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Chapter 27 Solutions
Genetics: Analysis and Principles
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