Ch. 27 HW ans key - temporary reduction in number. It...

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Ch. 27 HW ans key MCQ: 1) A 2) C 3) C 4) E 5) C T/F: 1) T 2) F 3) T 4) T 5) F SQ: 1) Large size, random mating, and not affected by migration, selection or mutation. 2) Inbreeding is a non-random mating between related individuals. Inbreeding leads to an increase in the proportion of homozygotes for recessive alleles and a decrease in the proportion of heterozygotes in a population. Because many recessive alleles are deleterious when homozygous, inbreeding increases the chance of manifesting the deleterious effect of those homozygous recessive alleles. It also results in lowered mean fitness of the population. 3) Genetic drift is the change in allelic frequencies due to chance deviation, when the effective population size is small. It can arise in three different situations; a) random fluctuation in small population size, b) through founder effect where the population has originated from a small number of founders and c) induced by genetic bottleneck which happens when a large population undergoes a drastic but
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Unformatted text preview: temporary reduction in number. It affects population by changing allelic frequencies, reducing genetic variation within population and increasing genetic variants among populations. Problems: 1) If we assume p represent the frequency of wild-type allele and q represents the mutant (loss-of-function) allele; and we assume that the population is in Hardy-Weinberg equilibrium, then the frequencies of the genotypes are given by p2 for homozygous normal, q2 for individuals with Tay-Sachs and 2pq for heterozygous carriers. q = q2 = 1/ 3600 = 1/60 = 0.017 Since, p + q = 1, p = 1- 0.017 = 0.983 Therefore, the frequency of carriers is, 2pq = 2 (0.017) (0.983) = 0.033 = 1 in 30. 2) Frequency of A = p = 0.2 + 0.6/2 = 0.2 + 0.3 = 0.5 q = 1-p = 0.5 In the second generation, Frequency of AA = (0.5)2 = 0.25 0r 25% Frequency of Aa = 2pq = 2 (0.5) (0.5) = 0.5 or 50% Frequency of aa = q2 = (0.5)2 = 0.25 = 25%...
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Ch. 27 HW ans key - temporary reduction in number. It...

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