0
In haemoglobin, there are four polypeptide chains that make it's structure, 2 (A) chains and 2 (B) chains. Sickle-Cell Anemia is caused by a mutation the (B) chain that makes the haemoglobin molecules stick to each other and form fibres inside the red blood cell (RBC).
Instead of a circular disc shaped RBC we now have a sickle shaped cell. This means transport of oxygen is very innefficient and the disease can cause death.
However, in areas with a high malaria rate, heterozygous sickle-cell anaemics (with some sickle shaped AND normal RBCs) are naturally selected because the protozoan (what causes the disease) is unable to live inside the red blood cell due to the fibres formed from the mutation, the cells are more fragile and they have a shorter life span than normal RBCs. This means that people with heterozygous alleles for sickle-cell anaemia benefit against malaria and will survive to reproduce, which increases the allele frequency of the sickle-cell anaemia allele.
Those with homozygous sickle-cell anaemia and those with homozygous normal haemoglobin are selected against as the first usually die of the sickle-cell anaemia, and the latter contract malaria.
NB. Mutations are rare occurrences. It is even rarer for a mutation to give selective advantage. This mutation for sickle-cell anaemia did not happen to 'cure' or prevent malaria, it was a random occurrence that coincidentally gave a selective advantage against malaria.
What else can I help you with?
Why are red blood cells sickle shaped in a person with sickle cell disease?
Sickle cell is common in people from tropical areas where malaria is prevalent. Malaria can not survive on blood cells that are sickle shaped, so when populations were being killed off by malaria, those with sickle cell were surviving and passing on the sickle cell gene.
Why is frequency of sickle cell allele so much lower in the US than in Africa?
People with sickle cell anemia are resistant to malaria, which increases their ability to survive and produce offspring. This is evolution in action. Since malaria is a bigger problem in Africa than in America, it is more prevalent in Africa. Many black people in America have inherited this gene from their ancestors
How natural selection means there is more sickle cell anemia in Africa?
Sickle cell anemia is more prevalent in Africa due to natural selection's role in conferring a survival advantage against malaria. The sickle cell trait (carrying one copy of the gene) provides some protection against the disease, allowing individuals with the trait to survive and reproduce more successfully in malaria-endemic regions. As a result, the frequency of the sickle cell allele increases in these populations, leading to higher rates of sickle cell anemia. This illustrates how environmental pressures can shape genetic traits within a population.
What Sickle cell disease is and which population?
sickle cell occurs in populations more toward africa, just like malaria.
Why is it beneficial to have Sickle cell anemia if you live in Africa?
In Africa, malaria is a common disease. It attacks healthy blood cells and uses them to travel throughout the body. However, if one has sickle-shaped blood cells, this makes it harder for the malaria to attach and travel through the body.
Can Mexican people get sickle cell anemia?
Sickle cell anemia is more common in populations from Africa, the Mediterranean, and the Middle East. It is uncommon in Mexican populations, but it is still possible for Mexican individuals to have sickle cell anemia, especially if they have ancestors from regions where the condition is more prevalent.
Why do people of Mediterranean and African decent have sickle cell anemia?
Sickle cell anemia is a inherited blood disorder. This means everyone who has sickle cell has inherited it from their parents. With this in mind it means there was a key ancestor in Africa or the Mediterranean who had the first sickle cell anemia and passed it on to their descendants.
What groups get sickle cell disease?
A person can only inherit sickle-cell genes if some of their ancestors came from certain regions in Africa where the inhabitants carry sickle-cell genes. A person with one sickle-cell gene has sickle-cell trait, a milder problem. If both father and mother pass on sickle-cell genes, the child, with two genes, will have sickle-cell disease.
Who has a sickle cell trait?
People who inherit one sickle cell gene are said to have sickle cell trait. This means they carry the gene but do not typically have symptoms of sickle cell disease. It is important for individuals with sickle cell trait to be aware of their status for proper medical management and genetic counseling.
Can you explain what evolutionary advantage mean and how it accounts for why sickle cell anaemia is still so widespread in Africa?
evolutionary advantage means that if you have to types of sickle cell anaemia and one is resistant to a drug the the other one is not then the one that is not resistant dies off and the sickle cell anaemia that is resistant becomes dominant and that is why sickle cell anaemia is still so widespread in Africa because the strain that is widespread in Africa is resistant is anti-biotics.
How prevalent is the disease sickle cell in the population?
its a very rare disease because you have to be heterozygous to have it! I KNOW I'M CLEVER
What are people with sickle cell resistant to?
Sickle cell anemia provides resistance to malaria - it is ideal for many people in Africa that live in mosquito rampant areas.
