The CCR5 gene codes for a protein on the surface of T cells. The CCR5 protein is used by Human Immunodeficiency Virus (HIV) to enter T cells, which ultimately leads to Acquired Immunodeficiency Syndrome (AIDS). AIDS was first reported in the European population in the early 1980s.
About 3000 years ago in Central-Western Europe a mutation occurred that prevents normal expression of the surface protein. People with one copy of the mutated allele have delayed onset of AIDS. Homozygotes for the mutation are resistant to HIV infection.
Evidence suggests that the trait also protects individuals from the smallpox virus. Smallpox was common in the European population from the Middle Ages until the early 1900s, causing several major epidemics with high death rates. It was eradicated through widespread vaccination.
The frequency of the allele is 16% in Scandinavia and 4% in Greece. What are the expected frequencies of HIV-resistant individuals in each population and which evolutionary explanation for the difference is most plausible?
The CCR5 gene codes for a protein on the surface of T cells. The CCR5 protein is used by Human Immunodeficiency Virus (HIV) to enter T cells, which ultimately leads to Acquired Immunodeficiency Syndrome (AIDS). AIDS was first reported in the European population in the early 1980s.
About 3000 years ago in Central-Western Europe a mutation occurred that prevents normal expression of the surface protein. People with one copy of the mutated allele have delayed onset of AIDS. Homozygotes for the mutation are resistant to HIV infection.
Evidence suggests that the trait also protects individuals from the smallpox virus. Smallpox was common in the European population from the Middle Ages until the early 1900s, causing several major epidemics with high death rates. It was eradicated through widespread vaccination.
The frequency of the allele is 16% in Scandinavia and 4% in Greece. What are the expected frequencies of HIV-resistant individuals in each population and which evolutionary explanation for the difference is most plausible?
The correct option is B The frequency of resistant individuals is expected to be .0256 in Scandinavia and .0016 in Greece. Higher rates of smallpox infections in Scandinavia created a selection pressure for the resistance allele.
The frequency of the dominant allele is p2, as the allele is able to express itself in heterozygous conditionThe allele also gives resistance to chicken poxThe probable reason for the increase in the number of alleles in the Scandinavian population is small pox infection, as this allele also protected the individuals from small pox, other than being resistant to HIV The frequency of the allele in Scandinavian population is 16%Being a dominant allele the frequency is (0.16)2 = .0256 and in Greece, the frequency of the allele is (.04)2 = 0.0016So, the correct answer is ' The frequency of resistant individuals is expected to be .0256 in Scandinavia and .0016 in Greece. Higher rates of smallpox infections in Scandinavia created a selection pressure for the resistance allele'
The frequency of the dominant allele is p2, as the allele is able to express itself in heterozygous condition
