Question

a form of hypertrichosis that causes hairiness of the pinna of the ear is inherited as a y-linked trait in humans. if a man with this form of hypertrichosis marries a non-hairy-eared woman, what genotypes may be found in their children?

Answer 1

Male children of a man with a Y-linked trait for hairy ears will inherit and express the trait, while female children will not inherit the Y chromosome and thus will not express hypertrichosis.

Step-by-step explanation:

If a man with hypertrichosis (hairiness of the pinna of the ear) which is a Y-linked trait marries a non-hairy-eared woman, their children's genotypes will vary based on their sex. Since Y-linked traits are only found on the Y chromosome and are passed from father to son, any male children will inherit this trait and exhibit hypertrichosis.

Since females do not inherit the Y chromosome from their father but rather an X chromosome, female offspring will not have hairy ears. Therefore, sons will have the genotype with the hypertrichosis allele on the Y chromosome (XYh), and daughters will have the normal X chromosomes (XX), not expressing the trait.

Answer 2

Answer: XX and XY⁻

Step-by-step explanation:

This trait is Y-linked, meaning that it can only be carried by male individuals. In this cross, let the man be represented by XY⁻, where Y⁻ represents the hypertrichosis. The woman will be XX.

X X

X XX XX

Y⁻ XY⁻ XY⁻

From this cross, you can see that all female children of this couple will have the genotype XX and will not inherit the genetic form of hypertrichosis because they will not inherit a Y chromosome. All male children of this couple will have the genotype XY⁻ and will inherit the genetic form of hypertrichosis. This is because the father HAS to pass his Y chromosome down to his male offspring, and he does not have an unaffected version to give them.