Below is a pedigree for a family that carries Falconi anemia, an autosomal genet

Question

Below is a pedigree for a family that carries Falconi anemia, an autosomal genetic disorder that causes bone marrow failure and decrease in the production of all types of blood cells. Dominant Falconi anemia allele (allele F) produces normal individuals, recessive allele (allele f) produces Falconi anemia disorder. Circles in the pedigree indicate women and squares indicate men. Filled symbols represent individuals with Falconi anemia, open symbols represent normal individuals who do not suffer from this genetic disorder.

a) What is the genotype of Mike at the Falconi anemia locus?

b) If Mike and Susan have another child, what are the chances this child will produce Falconi anemia disorder? Show your work by including a Punnett square.

c) If Ivy and Brian have another child, what are the chances this child will be a normal individual? Show your work by including a Punnett square.

Explanation / Answer

a) Mike has a genotype of Ff at the anemia locus. This is evident from the fact that Susan has a genotype of ff, if Mike had a genotype of FF then none of his children would have had the disease, but that's not the case. Hence Mike's genotype is Ff.

Genotype of all the memebers:

b)

Thus we see that the probability that the child will have the disorder is 1/2 or 50%.

c) Ivy has a genotype Ff and Brian has a genotype Ff.

The child will be normal if he has either FF or Ff genotype.

Hence the probability is 3/4 or 75%.

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