# Calculating frequencies of possible combinations of SNP genotypes in a population

Hi all,

I am looking to calculate the frequencies of all possible combinations of a group of SNP genotypes, in a population. This would be done based on the minor allele frequencies acquired in our population data. I just have a question on whether the following is the right way to do it:

If for example, we have three SNPs, their alleles, and their minor allele frequencies, with A2 being the minor allele:

``````SNP  A1  A2  MAF
SNPA  A   T  0.1
SNPB  C   G  0.3
SNPC  A   G  0.4
``````

And I now have compiled the possible genotype combinations from the three SNPs:

``````AA-CC-AA
AA-CC-AG
AA-CG-AA
AA-CG-AG
...
``````

and so on for 27 combinations.

In order to calculate the frequencies of each ‘profile’, would I simply multiply all the allele frequencies? For example, the first AA-CC-AA frequency would be:

``````(0.9)(0.9) x (0.7)(0.7) x (0.6)(0.6)
``````

While for the AA-CC-AG combination it would be:

``````(0.9)(0.9) x (0.7)(0.7) x (0.6)(0.4)
``````

Would this be correct?

Thanks!