Question

A pedigree is shown above that tracks a trait through three generations in a family. Analyze the inheritance of the trait

and select all of the statements that apply.

Answer 1

In the given pedigree, individual 1 has the recessive genotype (aa), while individual 2 and 3 have the dominant genotype (AA).

Step-by-step explanation:

In the given pedigree, let's analyze the genotypes of individuals labeled 1, 2, and 3:

1. The individual labeled 1 is affected by the trait (represented by a shaded circle). Since the trait is recessive, both copies of the gene must be the recessive allele. Therefore, the genotype of individual 1 is aa.

2. The individual labeled 2 is unaffected by the trait (represented by an open square). Since the trait is recessive, this individual is either homozygous dominant (AA) or heterozygous (Aa). Without more information, we cannot determine the exact genotype of individual 2.

3. The individual labeled 3 is unaffected by the trait (represented by an open circle). Since the trait is recessive, this individual must be homozygous dominant (AA) because they do not have the trait.

Answer 2

The justification and the analysis of the trait are:

• A) Individuals 1-1 and 11-4 are carriers.
• C) Males are being affected more frequently than females.
• E) The trait appears in later generations after being absent in one generation.

How to analyze the trait

A) Individuals 1-1 and 11-4 are carriers, meaning they carry the recessive trait without displaying it. This suggests a possibility of the trait being sex-linked.

C) Males are affected more frequently than females, indicating a higher occurrence among males, which is typical of sex-linked recessive traits where males (XY) only inherit one copy of the X chromosome carrying the trait.

E) The trait skipping generations implies a recessive trait carried on the X chromosome.