Question

The pedigree below shows two generations of individuals within a family. The pedigree shows

that a daughter has a genetic trait, even though neither of her parents nor her siblings have the
trait.
7. How can the daughter have the genetic trait if no one else in the family has it?
A. The trait is determined by a recessive allele.
B. The trait is not inherited.
C. The trait is determined by a dominant allele.
D. The trait is passed only from female to female.

Answer 1

The daughter likely has the genetic trait because it is determined by a recessive allele, meaning both her parents are carriers but do not exhibit the trait.

Step-by-step explanation:

The question pertains to how a daughter can have a genetic trait when neither of her parents nor her siblings have it, as shown in a pedigree chart. The most likely explanation for this scenario is Option A: The trait is determined by a recessive allele. This means that both parents could be heterozygous carriers of this recessive trait without showing it phenotypically. Each parent has at least one normal allele (represented as "A?") since they do not express the trait. However, the daughter, having inherited one recessive allele from each parent, is homozygous for the recessive allele and therefore expresses the trait. Mendel's theory of inheritance explains that recessive traits can skip generations and resurface if the individual receives two recessive alleles, while dominant traits cannot skip generations.

Answer 2

Answer: B The trait is determined by a recessive allele