Traits Inherited on Sex Chromosomes

Question 1

why is it important to understand how sex chromosomes are inherited?

Answer 1

To predict phenotypes and genotypes in offspring

Question 2

A female inherits her X chromosome from which parent?

Answer 2

Both

Question 3

X-linked traits are always passed on the X chromosome from mother to ____ or from either parent to ____. But there can be no direct ______ transmission of X-linked traits.

Answer 3

Son, Daughter.
male-to-male

Question 4

Genes carried on the X chromosome are said to be ____, and those on the Y chromosomes are ____.

Answer 4

X-linked, Y-linked

Question 5

What chromosome trait is rare?

Answer 5

Y-linked traits

Question 6

No other Y linked traits besides ______ are yet clearly defined, although certain gene products have been identified.

Answer 6

Infertility

Question 7

Human male having only one of a pair of genes, for X-linked traits, because he has only one set of X-linked genes.

Answer 7

Hemizygous

Question 8

Is expressed in females if the causative allele is present in two copies.

Answer 8

X-linked recessive trait

Question 9

an X-linked trait passes usually from an unaffected _______ to an _______.

Answer 9

Heterozygous mother, affected son.

Question 10

Criteria for an X-linked Recessive Trait

Answer 10

1. Always expressed in males
2. Expressed in female homozygous but very rare in a heterozygous
3. Passed from mother (heterozygote or homozygote) to son
4. No father to son transmission but could affect daughters
5. Both parents are affected/mother is heterozygote of an affected female
6. A heterozygous female will transmit the trait 1/2 to her son and 1/2 to her daughter.