# Help urgent biology q ‼️ 🧪

Help!
I don’t understand when to use q and when to use q^2. I mean for the 1st Q why is 15 equal to q squared but in the second question q is equal to 0.56 and it’s not q squared…
What I mean is how do I know if the number they give me is q or q squared???
(edited 10 months ago)
Because it depends on whether you are looking at the phenotype or genotype.
For the 1st example, you are looking at the probability of the recessive trait(which is the phenotype) which is coded for by 2 recessive alleles, so it has a genotype of qq, or q Squared. This means the actual frequency of the q allele is the square root of 0.075 (as each of the 15 snakes has 2 q alleles). So if you are given the phenotypes, square root the probability
But for q2, you are given the actual allele frequencies, so are already given q
Original post by Emmmaaaa...
Because it depends on whether you are looking at the phenotype or genotype.
For the 1st example, you are looking at the probability of the recessive trait(which is the phenotype) which is coded for by 2 recessive alleles, so it has a genotype of qq, or q Squared. This means the actual frequency of the q allele is the square root of 0.075 (as each of the 15 snakes has 2 q alleles). So if you are given the phenotypes, square root the probability
But for q2, you are given the actual allele frequencies, so are already given q

Thanks!!