Balanced polymorphism

[osimsDDS]

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Is balanced polymorphism the same thing as heterozygote advantage where a heterozygote may show multiple alleles and therefore can balance the two forms such as in sickle cell anemia of heterozygotes...where the carrier has a slight form of sickle cell anemia but because of this the person is "immune" to malaria

 

[HoangDDS]

not sure what "balanced poloymorphism" is, but I thought polymorophism is when there is more than one allele at one locus.

With sickle cell, I remembered that it is caused by a one base pair subsitution which somehow leads to sickle cell. And I do remembered that this mutation confer some resistance to malaria and thus survival advantage to individuals herteozygous for the mutation.

So, I think you got it. But this stuff is kinda vague to me.

 

[niktacal82]

hmm..let's say...heterozygote advantage is the mechanism of balanced polymorphism;
The ability of natural selection to keep frequencies of two phenotype stable in a population called BALANCED POLYMORPHISM. But how natural selection does that? by two mechanisms:
1) heterozygote advantage =the example you said
2) Frequency-dependent selection= goes with relationship between parasites and host; for example the parasite can only recognize type x receptor..so people with type y receptor are safe


hope this helps

 

[osimsDDS]

got it thanks