Sex-Linked Inheritance

Which of the following is an example of a sex-linked recessive disorder found on the X chromosome?

• Huntington's disease

• Duchenne muscular dystrophy

• Cystic fibrosis

• Red-Green Color blindness

What are the genotypes of female carriers of sex-linked disorders?

• X^HX^H

• X^hY

• X^hX^h

• X^HX^h

Tags

NGSS.HS-LS3-1

What are the genotypes of healthy males?

• X^hY

• X^HY

• XX^d

• XⁱY

In a Punnett square cross for sex-linked recessive disorders, what percentage of female offspring would be carriers of the disorder if the male parent is affected and the mother is healthy?

HINT: Draw out a Punnett Square

• 0%

• 25%

• 50%

• 100%

Tags

NGSS.HS-LS3-1

If a female carrier of a sex-linked disorder has a child with a male who is affected by the same disorder, what is the probability that they will have a daughter who is affected by the same disease?

• 0%

• 25%

• 50%

• 100%

Tags

NGSS.HS-LS3-1

NGSS.HS-LS3-2

In terms of X and Y chromosomes, explain why the sperm of the male determines the gender of the offspring.

• Because the female egg contains only X chromosomes, and the sperm can contain either X or Y chromosomes, determining the gender.

• Because the male sperm has no role in determining the gender of the offspring.

• Because the female egg can contain either X or Y chromosomes.

• Because the environment determines the gender of the offspring.

Tags

NGSS.HS-LS3-1

Explain why it is more common for males to express a recessive sex-linked trait (on the X chromosome) rather than females.

• Males have two X chromosomes, increasing the chance of expressing recessive traits.

• Females have two X chromosomes, which dilutes the effect of a recessive gene.

• Males have only one X chromosome, so a recessive gene on it will be expressed.

• Recessive sex-linked traits are not more common in males than in females.

What genotype should be placed in the box with a question mark?

• X^HX^h

• X^HX^H

• X^hY

• X^HY

Tags

NGSS.HS-LS3-1

NGSS.HS-LS3-2

What percentage of the offspring could be colorblind?

• 25%
• 75%
• 10%
• 0%

Tags

NGSS.HS-LS3-1

NGSS.HS-LS3-2

NGSS.HS-LS3-3

What is the phenotype for the following genotype:

X^HX^h

• carrier female

• healthy male

• hemophiliac male

• hemophiliac females

Tags

NGSS.HS-LS3-1