9. Is HIV resistance evolving in Great Britain? Some people carry a mutation tha
ID: 278002 • Letter: 9
Question
9. Is HIV resistance evolving in Great Britain? Some people carry a mutation that makes them resistant to a particular strain of HIV. This form of HIV resistance is inherited as a simple recessive Mendelian trait. In other words, there are 2 alleles. The dominant allele, ealled +t, makes one risceptible to infection, whereas the recesive mutant form (a) Do you predict that this form of HIV resistance is evolving over time in Britain? If so, by what mechanism(s)? If not, why not? Explain your reasoning completely.Explanation / Answer
Research has shown that about 10% of European population are resistant to HIV infection. This is due to the fact that they carry a genetic mutation in the gene that encodes the protein CCR5-A32. This mutated protein prevents the virus from entering the cells. The incidence of mutated gene is particularly high in Scandinavian population. Studies had shown that this mutated gene resulted from bubonic plague during bygone historic times. Plaque provided selection pressure that forced up the mutation frequency from 1 in 20,000 in the medieval times to 1 in 10 today.
No. The mutation is not evolving over time, cause there is no selection pressure among the population now.
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