is it possible to have a change in genotype frequency without having a change in allele frequency?

Question

nincompoop · Answer

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steve816 · Answer

nin you alive?

hannansm · Answer

Yes.
If you rearrange the alleles, without changing their overall total number.
For example, 
Bb bb bb BB BB,
the genotype frequency for BB is 2/5 (or 0.4), right? 
And the allelic frequency for B is 5/10 (or 0.5).
However, if we rearrange this to 
Bb Bb Bb Bb Bb, you can see that the genotype frequency for BB is 0/5 (or 0),
And the allelic frequency for B is still 5/10 (or 0.5).

hannansm · Answer

The genotype frequency refers to the frequency of a certain COMBINATION of alleles (e.g frequency of BB),
while the allelic frequency refers to the frequency of the alleles themselves (eg frequency of B).