X-linked recessive traits mastery

If a gene is found only on the X chromosome and not the Y chromosome, it is said to be 

• sex-linked trait
• dominant trait

• codominant trait
• incomplete dominance trait

What percentage of all the offspring will have this recessive disease?

• 0%

• 25%

• 50%

• 75%

What percentage of the female offspring will be a carrier for this recessive disease?

• 0%
• 50%
• 100%
• 25%

Hemophilia is a recessive x-linked disorder.
Which genotype represents a female who is a carrier for hemophilia?

• X^HX^h
• X^hX^h
• X^HX^H
• X^hY

Hemophilia is a recessive x-linked disorder.
Which genotype represents a male with hemophilia?

• X^HX^h
• X^hX^h
• X^HY
• X^hY

H= normal blood clotting

h=hemophilia

X^HX^h x X^HY are the parents in this mating.

What is the probability that any of their male offspring will have hemophilia?

• 4/4

• 3/4

• 2/4

• 1/4

Look at this cross: X^B X^B x X^b Y

What percent of any of their female children are colorblind?

• 100%

• 75%

• 25%

• 0%

Colorblindness is more common in males than in females because......

• fathers pass the allele for colorblindness to their sons only

• the allele for colorblindness is located on the Y chromosome

• the allele for colorblindness is recessive and located on the X chromosome

• males who are colorblind have two copies of the allele for colorblindness

In fruit flies, eye color is a sex linked trait. Red (R) is dominant to white (r). What is the sex and eye color of flies with the following genotype: X ^R X ^r ?

• male with white eyes

• female with red eyes

• male with red eyes

• female with white eyes

In fruit flies, eye color is a sex linked trait. Red is dominant to white. What is the sex and eye color of flies with the following genotype: X ^R X ^R ?

• male with red eyes

• female with red eyes

• male with white eyes

• female with white eyes