Write a 9 pages paper on malaria resistant humans. Polymorphisms are one of the reasons for the resistance to the infection of Plasmodium vivax. The variations conferring to the resistance have evolved from about 1000 – 5000 years. Many variants have been discussed for malaria. Some of them are globin, G6PD deficiency, Duffy, ovalocytosis, ABO, and human leukocyte antigen variants. (Zimmerman et al. 1999). The most studied aspect of malaria resistance in humans is hemoglobin molecules. It was Haldane, who brought in 1949 into light about the link between genetic blood disorders and malaria protection. (Zimmerman et al. 1999). Mutation, natural selection, and migration are important mechanisms that play a major role in genetics. There is some interrelation between humans and malaria. Genetic factors and the higher levels of anti-malarial antibodies in particular ethnic groups are the major reasons for malarial resistance to humans.
The hemoglobin molecule is a protein that contains two alpha and two beta subunits. The genes encoding these subunits have many alleles. These alleles are largely affected by the point-mutations in the DNA sequence. Point mutations alter a single amino acid in the protein and reduce the red blood cells’ oxygen transport efficiency. (Sibinga and Klein 2000). In Africa in the sub-Sahara region, an abnormality was studied at the beta subunit of the hemoglobin molecule. The high frequency of the allele was the result of the point mutation. The glutamic acid in the beta subunit was replaced by valine. This change created change in the shape of the hemoglobin molecule. (Walliker, Walliker and Chappell 1996). The mutation crystallized hemoglobin under low oxygen tension and the red blood cell shape changed from normal platelet shape to sickle-shaped. The patients are identified to have developed malaria resistance. Malaria resistance in humans might have occurred by modification in the immune system and the native genetic resistance.
Genetic resistance to malaria is observed in some groups of people in sub- Sahara and South East Asia. (Sibinga and Klein 2000). Malaria resistance is conferred in the genes of the people. It is a type of genetically controlled immunity present in some people to control the disease at the beginning stage itself. The lack of the expression of the gene Duffy antigen receptor for chemokines (DARC) in the blood cells of the sub-Saharan region has resulted in the high malaria resistance in those people. The DARC negative individuals contain a single point mutation in the 46th position. (Sibinga and Klein 2000). .