Question

What about tracking an autosomal dominant trait, such as having a widow's peak? The presence of one dominant

allele for this widow's peak hairline (H) will result in an individual having a widow's peak. Since this pedigree is

tracking an autosomal dominant trait, shaded shapes have a widow's peak hairline. *Note: In reality, this trait may

be more complex than just a simple gene.

Hh

hh

I

hh

HH

II

?

?

1

2

23.

How many dominant alleles does an individual need in order to have the autosomal dominant trait?

24.

Is it possible to know the genotypes of the three children in generation III?

1

notes

No

Answer 1

Note about the question: You will find the pedigree in the attached files (PNG).

Answer:

• Third generation genotype: Hh
• How many dominant alleles does an individual need in order to have the autosomal dominant trait? An individual only needs one dominant allele H
• Is it possible to know the genotypes of the three children in generation III? Yes, because there is only one possible genotype
• The whole third generation in the pedigree should be shaded.

Explanation:

Due to technical problems, you will find the complete explanation in the attached files (PDF).