Question

The delta-32 allele has the LOWEST frequencies in areas where

a-HIV infection is rare
b-HIV strains are missing the viral protein Nef
c-HIV contains the CD4 receptor within its RNA genome
d-HIV infection is rampant or abundant

Answer 1

The CCR5-Δ432 mutation inhibits the viral entry step of the HIV life cycle by preventing HIV from binding to the CCR5 co-receptor on T cells. It is prevalent in northern Europe and might have been selected due to exposure to other diseases. This knowledge informs strategies for HIV drug development and prevention.

Step-by-step explanation:

Individuals with the CCR5-Δ432 mutation exhibit resistance to certain strains of HIV because the mutation prevents HIV from binding to the CCR5 co-receptor on the surface of T cells, which is a necessary step for the virus to enter and infect the cell. This mutation likely inhibits the viral entry step of the HIV life cycle. The presence of this mutation is highest in populations from northern Europe and has been found to predate the emergence of HIV, suggesting it was selected for due to exposure to other diseases like the plague or smallpox. Today, this research informs HIV treatment strategies, such as developing drugs that block HIV from binding to CCR5 in individuals without the mutation. However, reliance on the mutation for protection is discouraged due to rare cases of HIV infection in those with the mutation, and the continuing need for safe practices to prevent HIV transmission.