0
What else can I help you with?
The mutant allele causing sickle-cell anemia is found at high frequency mainly due to?
Sickle cell anemia is found in high frequency because it is a codominant mutation. It only requires one allele for the gene to manifest.
If malaria were eliminated how might the frequency of the sickle-cell allele change over time?
Since people with the sickle cell allele trait are resistent to malaria, if malaria were eliminated there would be no change in the frequncy of sickle cell allele. This is because the presense of malaria does not have an affect on patients with the sickle cell allele trait.
What are the pros for SICKLE CELL ANEMIA?
The pro of sickle cell hemoglobin is that if you have only one allele for sickle cell hemoglobin and the other allele is normal, then you are immune to malaria.
The allele for the sickle cell trait is what with the normal allele?
The allele for the sickle cell trait is codominant with the normal allele. This means that in individuals with both alleles present, both traits are expressed.
Which individuals have the greatest fitness in an area where malaria is common?
Individual homozygous for the sickle cell anemia allele
Being a carrier of sickle cell anemia means?
sickle cell anemia is caused by a recessive allele. so for it to affect someone, it means that the person must have received both recessive alleles from their parents. Being a carrier means that you have the recessive allele from one of your parents, but you have a normal dominant allele from the other parent, that means you are not affected by it but you are carrying it.
What is the name of the selective force acting on the population in the simulation lab on allele frequencies and sickle cell anemia?
Eubacteria
If sickle-cell anemia is so destructive why hasn't the sickle-cell allele been eliminated from the population?
It is important to note that sickle-cell anemia comes in two forms. The homozygous sickle-cell anemia and the heterozygous sickle-cell trait. The difference between the two is that sickle-cell anemia has a high rate death rate at a young age (20~), and the sickle-cell trait is nearly asymptomatic.In regions such as North America, sickle-cell anemia would be selected against and would eventually leave the gene pool. The sickle-cell trait on the other hand, has little effect on the fitness of the organism, and as such will remain in the gene pool.In malaria endemic regions such as sub-Sahara Africa, sickle-cell anemia provides very high levels of immunity to malaria and the sickle-cell trait provides a slightly lesser level of immunity. Both forms of sickle-cell will increase the organisms fitness and as such, it will remain in the gene pool. Further on, the sickle-cell trait has greater fitness than sickle-cell anemia, hence, the sickle-cell trait will be selected as the fittest allele.If s is the sickle-cell allele and S is a normal allele;The relative fitness in malaria endemic regions;Ss > ss > SSSickle-cell trait > Sickle-cell anemia > NormalThe relative fitness in non-malaria endemic regions;SS > Ss > ssNormal > Sickle-cell trait > Sickle-cell anemia
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.
How does a person with sickle-cell allele differ from a person with two sickle-cell alleles?
If a person has a single sickle cell allele they will have some sickles red blood cells, and some normal red blood cells. This is the origami purpose that this evolved for. If a person had a single sickle cell allele, they will be mostly resistant to malaria. This is why sickle cell anemia is most prevalent in areas of the world where malaria is common. However, if a person has two sickle cell anemia alleles, they will have ONLY sickled red blood cells. The "sickling" of the red blood cells is caused by a mutation in the protien that the gene codes for. That protein is hemoglobin, which carries oxygen through the blood. If a person has sickle cell anemia, parts of their body wil not get enough oxygen. They can pass out, loose sensation in the limb, or even die from it. In short, a person with two alleles is sick, and a person with one allele is not.
Can a person who has been successfully treated for sickle cell disease still transmit the disease-causing allele to offspring?
Sickle-cell anemia can only be transmitted if both partners have the disease.
What was primarily acting to change the frequency of the sickle-cell allele in the overall U.S. population?
The absence of the selection pressure malaria. Without selection, in the form of the malarial environment, the sickle cell allele will be lost in the overall US population. Even the heterozygous condition is somewhat deleterious and, statistically without malarial selection pressure the allele will be selected out.
