Question

Question 18 0/0.5 pts People who are __have a selective advantage in areas where Anopheles mosquitoes carrying the Plasmodium falciparum parasite are prevalent. homozygous for the sickle cell gene heterozygous for the sickle cell gene homozygous for the normal globin gene

Answer 1

Answer is option (2)

sickle cell trait (heterozygous) have the advantage of staying malaria free (causes by plasmodium ) throughout their lives and not individuals who are homozygous

sickle cell anaemia is a rare conditions and is inherited as an autosomal recessive trait which means the indiviidual needst to have both recessive alleles to be called as someone who has the disease. but this diseased individuals are actually at a lethal risk of malaria.

Research has found out that individuals who have a heterozygous sickle cell gene have an advantage of carrying a sickle trait which otherwise doesnt cause them the disease but helps them confering protection against malaria.

this protection is confered because the plasmodium cannot really enter the RBCs' that are sickle shaped and cause its effect by multiplying. this is mainly because the plasmodium produces a toxic substancs potassium in the cell and because the cell layer of the RBC in a patient with sickle cell is porous, the potassium thus leaks out of the cell making them resistant to malaria.

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