Why has sickle cell anemia been maintained in the human population?

Answer 1

Sickle-Cell AnaemiaSickle cell anemia is a disease that is controlled by alleles S and s .three possible combinations are SS , Ss ans ss . The most important reason why this allele is present in whole world including America is heterozygous superiority which keeps this gene in population

Several major Universities whose main function is Technology, along with the Medical Schools associated with teaching in the Children's Hospitals have begun joining forces using Nanotechnology to alter the genetics of the sickle cell trait. Among them is a collaborative effort between GA Institute of Technology, Emory University Medical School, and Children's Health Care Systems of Atlanta. Once this is accomplished, plans are already in the works to move on to another deadly disease initiated with inherited genes: Cystic Fibrosis. This is an excellent collaborative use of each genre's best abilities: cooperation vs competition.

I earlier times this may have been negatively associated with eugenics, however that connotation is now being transformed with the positive aspects of actually changing genetics at the microcellular level to rid populations of certain killer traits, rather than attempts at 'perfecting the human race,' as in the despicable times of Hitler. This is not a genocidal experiment, but one aimed at saving lives of painful and deathly diseases, remembering sickle cell trait is mostly among Blacks.

To get a clearer picture of why the allele is still present, just remember what the Hardy-Weinberg principle predicts:

both allele and genotype frequencies in a population remain constant; that is, they are in equilibrium from generation to generation unless specific disturbing influences are introduced. Those disturbing influences include non random mating, mutations, selection, limited population size, "overlapping generations," random genetic drift, gene flow and meiotic drive.

Since the homozygous recessive (when the Anaemia is actually expressed) and heterozygous condition do not affect mating probabilities, the allele will naturally remain within the population.

Answer 2

Sickle cell anemia has been maintained in the human population because carrying one copy of the sickle cell gene provides some protection against malaria, particularly in regions where the disease is endemic. This genetic advantage has led to the persistence of the sickle cell gene in certain populations over time.

Answer 3

If I remember correctly, sickle cell anemia selects for resistance to malaria. Thus, if a population living in a a malaria-prone area (e.g., equatorial Africa?) develops sickle cell anemia, they will live longer and be more likely to reproduce than someone who dies sooner from malaria.

Answer 4

In Malaria endemic regions in Africa, the homogenous sickle cell and heterogeneous trait would be selected for, as it increases the probability that the human will reach the age of fertility and be able to reproduce.

It should also be mentioned that since the heterogeneous sickle cell trait is nearly asymptomatic, natural selection has little effect on it in places where Malaria does not exist. On the other hand, the homogeneous sickle cell would be selected against in regions without Malaria due to its fatal side effects.

Answer 5

The sickle cell gene has persisted because people heterozygous for sickle cell (with one normal gene and one mutated gene) are usually asymptomatic and are also more resistant to malaria than those without the mutation. They don't suffer the same problems as those who have two copies of the mutated gene (debilitating pain, early death, etc.). They may have some red blood cells that are sickle-shaped, but many of their red blood cells are normal.

Sickle cells are destroyed by the body more quickly than more red blood cells, which could play a part in this resistance to the disease. Malaria parasites would be more likely to be destroyed during this process. The sickle cells themselves may also help destroy the parasites by contributing to the formation of free radicals, which damage DNA.

Answer 6

Okay now for the answer, Sickle cell anemia is inherited when both parents pass the Hemoglobin S gene (trait) to their offspring (Defective trait that codes for sickle RBC). If only one parent has the Hemoglobin S trait then that child (ren) will only have the sickle cell anemia trait but will not have the sickle cell anemia disease, meaning they carry the gene in their DNA, but it won't nearly affect them as bad as the disease will. The allele of the hemoglobin S trait gene (is heterozygous), but does not display the severe symptoms of sickle cell disease that occur in a person who has two copies of that allele. Those who are heterozygous for the sickle cell allele produce both normal and abnormal hemoglobin (the two alleles are co-dominant).*The trait does not mean you have the disease it just mean you are a carrier for sickle cell anemia).

One of the benefits to carrying the trait of sickle cell is that you are less likely to get malaria, because the virus can't settle on the sickled cells

In simpler less complicated words if both parents have the Hemoglobin S trait then that child will have Sickle cell anemia. Basically both parents have to have the Hemoglobin S trait for their child to get it. So, if I were too have a child and I only have the trait (not the disease) with someone who has sickle cell anemia trait as well then our child will have sickle cell anemia disease, and same result if I had the disease and I had a child with someone who also had the disease. Here is a punnett square diagram that shows you visually how these situations would work. A punnett square is a diagram that can be used to predict the genotype and the phenotype combinations of a genetic code. And thats not only part of my project but the reason why it has lasted in the population.

Answer 7

Because people with the sickle cell gene are protected against malaria. Populations where malaria is prevelant have a higher rate of sickle cell genes because it has been selected for.

Answer 8

Because sickle-cell gene protect against malaria.