Question

Describe what malaria is and where it is prevalent – in what areas of the globe and in what habitats? Describe how an individual’s genotype influences their chance of contracting malaria: Which individual is more likely to get malaria -an individual with two HbA alleles or an individual with one HbA allele and one HbS allele? Why? Describe the effect of malaria on the frequency of the HbS allele in areas where malaria is common: In areas with malaria, which individual would survive better and leave more offspring – an individual with two HbA alleles or an individual with one HbA allele and one HbS allele? Given this, would you expect the HbS allele to be common or rare in populations living with malaria? If the malaria parasite is eradicated from an area where it used to be prevalent, what would you expect to happen to the frequency of the HbS allele in the population?

Answer 1

Malaria is parasitic disease which is topmost leading cause of death in tropical countries. It is caused by malarial parasite called plasmodium genus of protozoan which spread through vector female anopheles , mosquito.

Mostly it's common in hot and humid climate like Asia African continents

Malarial parasite required human RBC and liver for completing thier life cycle. Now shape of RBC is determined by genotype as we know HbAHbA is normal in shape RBC while heterogygous HbAHbS is carrier and acting as normal person as half of HB gene produce normal RBC while HbSHbS is recessive genotype which does not survive due to sickle shaped structure.

While normal HbAHbA is having normal shape RBC which does not survive in malaria epidemic zone due to infection of malaria so only heterozygous individual will be survived as in heterogygous as neither malaria nor sickle cell anemia occurs in these indivisuals.

The frequency HbS allele will be 50% in heterogygous individual.

Hope it's clear..thanks