Question

as a genetic counselor, you are given the following family tree to predict the genotype and phenotype of the following couples offspringgrandparent 1: does not have marfan syndromegrandparent 2: has marfan syndromegrandparent 3: has marfan syndromegrandparent 4: does not have marfan syndromeparent 1: does not have marfan syndromeparent 2: has marfan syndromechild 1: ?part ausing the information provided in the diagram, determine the genotype of parent 1 and parent 2.parent 1: parent 2:

Explanation:

Step1: Identify Marfan inheritance type

Marfan syndrome is autosomal dominant. Let the dominant allele be $M$, recessive be $m$. Unaffected = $mm$, affected = $Mm$ or $MM$.

Step2: Deduce Parent 1 genotype

Parent 1 is unaffected. For autosomal recessive unaffected, genotype is $mm$.

Step3: Deduce Parent 2 genotype

Parent 2 has Marfan. Parent 2 inherits from Unaffected Grandparent 4 ($mm$), so must get $m$ from them. Thus, Parent 2 is $Mm$.

Answer:

Parent 1: $mm$
Parent 2: $Mm$