Sea otter is an endangered species of northern pacific ocean

Sea otter is an endangered species of northern pacific ocean. Allele frequencies for two microsatellite loci for a small Californian population of sea otters on San Nicolas Island are shown below.

If a female otter has the genotype 144/144 129/131 and her offspring has the genotype 144/146 129/131, what is the probability that you could rule out a randomly chosen male in this population as the father?

b) There are two candidate males (named Hagrid and Snape) that are candidates to be the father of the offspring described in part (a). Which is most likely?
Hagrid: 144/146 129/129           Snape: 146/152 131/13

Solution

the genotype of the offspring to be 144/146 129/131, the other parent must contain one 146 allele and one either 129 or 131 allele. therefore, the individuals with 146, 129 and 131 alleles can most likely contribute to such offsprings. the individuals who do not contain these alleles cannot be a father.

since the frequency of 146 is 0.21, i.e, 0.21 chances that the individual can be a father. similarly, the conjugative frequency of 129 and 131 alleles is 0.45, 0.45 chances that the individual can be a father. probability to be a father = 0.21 x 0.45 = 0.09. i.e, 9 out of 100 is the possibility to be father. remaining 91 out of 100 are chances not be a father or 0.91.

b. both of them can be father. if hagrdis id the father, the child may be either 144/144 or 144/146 and 129/129 or 129/131. possible genotypes- 1. 144/144 129/129 2. 144/144 129/131 3. 144/146 129/129 4. 144/146 129/131

if snape is father, possible genotypes- 1. 144/146 129/131 2. 144/146 131/131 3. 144/152 129/131 4. 144/152 131/131.

both have equal chance