# Hardy-Weinberg principle question A level biology codominant alleles?

Hi please can someone help with this WJEC A level question?

I can't work out how to do them if the alleles are codominant? I understand how to work out homozygous recessive, dominant and heterozygous in the usual questions and I get the answer to the first part as 55% but really stuck on the others. Please help! Thanks

I - 55%
II - 3025
III - 2025
IV - 4950

In addition to the ABO blood group system in humans there is another system called MN. It is caused by codominant alleles, M and N which code for proteins in the membrane of red blood cells.

(a) (ii) The frequency of allele N in Germany is 45%.

Calculate the following given that:
p = frequency of allele M,
q = frequency of allele N,
p + q = 1
p2 + 2pq + q2 = 1

I. The % frequency of allele M; [1]
.................................
II. The number of individuals in a population of 10000 with blood group M; [1]
.................................
III. The number of individuals in a population of 10000 with blood group N; [1]

IV. The number of individuals in a population of 10000 with blood group MN. [1]
(edited 1 year ago)
I do AQA but we also look at Hardy-Weinberg! With codominance it doesn't really matter what you put down as p or q, it's just something to assign the two different homozygotes.
Hi v.genericname, I get it now, thank you SO much!!