biology question?

Question

Individuals who are heterozygous for the sickle cell allele are resistant to malaria. Does this fact mean that the frequency of the sickle cell allele will change in an area where malaria occurs? Explain why.

Answer 1

The incidence of sickle cell allele is increased in malaria endemic regions.

As stated, heterozygotes are resistant to malaria. Homozygotes die out.

In malaria-free areas, there is a very low frequency of the allele because it confers no advantage and over time enough people who have had the allele and passed it on have diluted it out to a low frequency. The people who do not have the allele reproduce as well as those who doo, and of those who do there is a small proportion of their children who will be homozygous and thus die out. There is in fact a small selection bias against the sickle cell allele.

In malaria-endemic areas, people who do not have the allele are at a survival disadvantage because they catch malaria. Those who are heterozygous tend to do better because they are resistant to malaria. They reproduce more frequently and pass on the allele. Some children born to them who do not have the allele are selected against because they contract malaria.

Oh yes
and cos God wants them to suffer

Answer 2

I believe so, if malaria is in area were there is sickle cell also. That's actually the reason why African-Americans carry the trait now, higher allele frequencies enable the trait to be passed from generation to generation. Its a matter of selection. Whenever malaria began to show up, those who were carriers for of the sickle cell trait survived malaria, those who did not have the trait were more likely to die from the disease, as well as those who had full sickle cell anemia.

Answer 3

Yes that's what it means. Think of it like this. It would be an advantage to be resistant to malaria in an area where malaria is present. Individuals that have this sort of resistance would tend to survive better than individuals that did not, thus the resistant ones would increase in numbers and thus increase the number (or frequency of occurence) of their resistant sickle cell genes within the population.

Answer 4

I don't think so because if the frequency increases it could mean that the quatity of people who are homozygous for sickle cell could increase. They might not be able to pass on their genes to their offspring. This would keep the allele frequencies in check. not to mention that if people who are homozygous with regular alleles are present, they would die as wel and might not be able to pass on their genes either. In this case where the heterozygote is the most fit to the environmet, the allele frequencies don't change.

Answer 5

because God designed it and planned for them to suffer...or maybe, because the gene helps people survive who have malaria--thus the gene has survival value and it is preserved...or ....remember it's God's Plan...Let us Pray...