help needed with all of them please A pesticide resistance allele was at a frequency of 50% in a population of flies. The pesticide was no longer effective because of the prevalence of resistant flies. Ranchers decided to stop using the pesticide, and in 20 years the resistance allele dropped to a frequency of 5%. The allele is autosomal, affects fitness in an additive fashion, and there are two fly generations per year. a) Explain in 1—2 sentences why natural selection may have caused a decrease in the frequency of the resistance allele. b) What is the selection coefficient acting against homozygotes for the resistance allele (in the absence of the pesticide)? c) What was the frequency of the resistance allele one generation after ranchers stopped using the pesticide (i.e., after one generation of viability selection)? Assume that the population was in Hardy-Weinberg equilibrium when ranchers stopped using the pesticide and the population underwent random mating. d) The effective population size of these flies is 500,000 individuals. Starting from today (i.e., resistance allele at a frequency of 5%), how many years do you expect it will take for the resistance allele to be lost from the population?

Biology: The Unity and Diversity of Life (MindTap Course List)
14th Edition
ISBN:9781305073951
Author:Cecie Starr, Ralph Taggart, Christine Evers, Lisa Starr
Publisher:Cecie Starr, Ralph Taggart, Christine Evers, Lisa Starr
Chapter13: Observing Patterns In Inherited Traits
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help needed with all of them please

A pesticide resistance allele was at a frequency of 50% in a population of flies. The pesticide was no longer effective because of the prevalence of resistant flies. Ranchers decided to stop using the pesticide, and in 20 years the resistance allele dropped to a frequency of 5%. The allele is autosomal, affects fitness in an additive fashion, and there are two fly generations per year.

a) Explain in 1—2 sentences why natural selection may have caused a decrease in the frequency of the resistance allele.

b) What is the selection coefficient acting against homozygotes for the resistance allele (in the absence of the pesticide)?

c) What was the frequency of the resistance allele one generation after ranchers stopped using the pesticide (i.e., after one generation of viability selection)? Assume that the population was in Hardy-Weinberg equilibrium when ranchers stopped using the pesticide and the population underwent random mating.

d) The effective population size of these flies is 500,000 individuals. Starting from today (i.e., resistance allele at a frequency of 5%), how many years do you expect it will take for the resistance allele to be lost from the population? 

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