Question

Consider a population having the following genotypes: Nn, Nn, NN, Nn, nn, Nn, NN, nn, Nn, nn.

1. What is the frequency of genotype NN?
2. What is the allelic frequency of n?
3. Based on what you know about Mendelian genetics, would you expect genotype Nn to more closely phenotypically resemble nn or NN?

Answer 1

Answer a :

There are 10 given individuals  with three different genotypes
There are 2 individuals with the genotype NN
Therefore frequency of genotype NN = 2/10 = 0.2

Answer b:

There are 10 individuals given. They have 2 alleles each.
Therefore there are a total of 20 alleles

The allele n is present 11 times in all the genotypes (Heterozygous or homozygous)
Therefore frequency of allele n = 11/20 = 0.55

Answer c :

The genotype Nn has a dominant allele N and a recessive allele n. Because N is dominant, the phenotype expressed by Nn will be similar to the phenotype expressed by the individuals with genotype NN.
The recessive allele is only expressed in genotypes where both the alleles are recessive - nn