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Question about Genetics: Exercises

Subject Biology

Biology

Source CEFET-PI

CEFET-PI

Topic Genetics: Exercises

Genetics: Exercises

Difficulty Medium

Medium

(CEFET-PI 2009) - Question Medium of Biology

Double-edged sword: Gene that confers resistance to malaria makes Afro-descendants more susceptible to HIV. A variant of a gene that provided resistance to a form of malaria increases by 40% the chances of being infected by HIV, the virus that causes AIDS. However, once infected, these individuals have a slower progression of the disease and live an average of two years longer. The gene in question is responsible for an antigen receptor present mainly in the membranes of red blood cells. Found predominantly in Afro-descendants, the variant of this gene (or allele) studied by researchers was selected thousands of years ago in Africa because it provided resistance to a form of malaria.

The HIV virus is a retrovirus and therefore carries a reverse transcriptase enzyme that makes a DNA strand from an RNA strand.

Individuals carrying the receptor are more susceptible to HIV.

The gene in question is the main selector of the population where it contributes to increasing the variability of individuals when they become vulnerable to HIV attack.

In the text, we can suggest a side effect of evolution, as the individual, while showing resistance to one event (malaria occurrence), acquires another disadvantageous one (susceptibility to HIV contamination).

Malaria is a protozoan disease transmitted by the bite of the female Anopheles mosquito.

Answer sheet:

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