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Sickle-cell disease was the genetic disorder to be linked to a mutation of a specific protein. Pauling introduced his fundamentally important concept of sickle cell anemia as a genetically transmitted molecular disease. [20] This vein (4) shows the interaction between the malaria sporozoites (6) with sickle cells (3) and regular cells (1).
Sickle-cell disease and the associated trait are most prevalent in Africa and Central America, which is attributed to natural selection: the sickle-cell trait confers a survival advantage in areas with a high occurrence of malaria, which has a high death rate among individuals without the trait. [citation needed]
Sickle cell disease (SCD), also simply called sickle cell, is a group of hemoglobin-related blood disorders typically inherited. [2] The most common type is known as sickle cell anemia. [2] It results in an abnormality in the oxygen-carrying protein haemoglobin found in red blood cells. [2] This leads to the red blood cells adopting an abnormal ...
Anthony Clifford Allison (21 August 1925 – 20 February 2014) was a South African geneticist and medical scientist who made pioneering studies on the genetic resistance to malaria. [2] Allison undertook his primary schooling in Kenya, completed his higher education in South Africa, and obtained a BSc in medical science from the University of ...
He further observed that these were favourable traits (heterozygous inheritance of sickle cell trait) for natural selection that protected individuals from receiving malarial infection. [91] He introduced his hypothesis at the Eighth International Congress of Genetics held in 1948 at Stockholm on a topic "The Rate of Mutation of Human Genes". [92]
It was noted in the 1920s that black Africans had some intrinsic resistance to malaria, but the basis for this remained unknown. The Duffy antigen gene was the fourth gene associated with the resistance after the genes responsible for sickle cell anaemia, thalassemia and glucose-6-phosphate dehydrogenase.
Thus, in regions where malaria exerts or has in the past exerted a strong selective pressure, sickle cell anaemia has been selected for its conferred partial resistance to the disease. While homozygotes will have either no protection from malaria or a dramatic propensity to sickle cell anemia, heterozygotes have fewer physiological effects and ...
The malaria parasite can exert a selective pressure on human populations. This pressure has led to natural selection for erythrocytes carrying the sickle cell hemoglobin gene mutation (Hb S)—causing sickle cell anaemia—in areas where malaria is a major health concern, because the condition grants some resistance to this infectious disease. [8]