Question

The above pedigree shows a particular inherited trait. The first-generation father passes the trait on to all his daughters and none of his sons. His daughters pass the trait on to half of their children regardless of gender. Based on this information, which of the following statements about the expressed trait is most likely correct?
A.
It is a sex-linked dominant allele.
B.
It is an autosomal recessive allele.
C.
It is a sex-linked recessive allele.
D.
It is an autosomal dominant allele.

Answer 1

The correct answer is option (A) it is a sex-linked dominant allele.

Pedigree analysis helps to determine the different modes of inheritance like the dominance, recessive, sex-linked, autosomal, mitochondrial and others. It helps in knowing the probability of affected offsprings in a cross.

In a sex-linked dominant inheritance, the father passes their X chromosome to daughters only. Of his daughters, 100% percent will have the inheritance as daughters inherit their father's X chromosome. Mother passes her X chromosome to both the sons and daughters or it is passed on to the offspring irrespective of their gender. Of her sons and duagters, 50% will have the inheritance.

In the pedigree of a particular inherited trait given above, the father passes the trait in the first generation to all his daughters and none of his sons. These daughters to half of their children regardless of the gender. Hence, it is a sex-linked dominant allele inheritance.

Answer 2

I'm pretty sure its A