Search results
Results from the WOW.Com Content Network
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]
This is an example of balancing selection between the fierce selection against homozygous sickle-cell sufferers, and the selection against the standard HgbA homozygotes by malaria. The heterozygote has a permanent advantage (a higher fitness) wherever malaria exists. [5] [6] Maintenance of the HgbS allele through positive selection is supported ...
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 ...
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]
Natural selection is the differential survival and reproduction of individuals due to differences in phenotype. It is a key mechanism of evolution, the change in the heritable traits characteristic of a population over generations. Charles Darwin popularised the term "natural selection", contrasting it with artificial selection, which is ...
Having a sickle-cell allele does limit the life expectancy of a person, however, the presence of sickle-cell genes reduces the detrimental effects of malaria should it be contracted. Natural selection allowed for the spreading of the sickle-cell gene in areas of high numbers of mosquitoes carrying malaria; those that weren't as susceptible to ...