Sex-Linked Traits

What is the inheritance of color blindness an example of?

• co-dominance

• continuous variation

• karyotype cross

• sex linkage

For haemophilia, let H be the normal allele and h the mutant allele.

Which is the genotype of the unaffected male?

• X^hY

• X^HX^H

• X^HX^h

• X^HY

Tags

NGSS.HS-LS3-1

Which of the following explains why color blindness is more common in males? Tick two.

• The mutant allele for color blindness is carried by the X chromosome.

• The mutant allele for color blindness is carried by the Y chromosome.

• Male has only one X chromosome, so either allele is expressed.

• Female has two X chromosomes, so either allele is expressed.

Tags

NGSS.HS-LS3-1

Color blindness is carried by the X chromosome.

A mother is a carrier of color blindness. Her husband has normal vision.

The probability of having a color blind offspring is (a)   percent.

Tags

NGSS.HS-LS3-1

NGSS.HS-LS3-3

The diagram shows the sex chromosomes of a woman and of a man. Their genotypes for a recessive sex-linked condition are also shown.

What are the chances that their daughter will show the sex-linked condition?

• 0%

• 25%

• 50%

• 75%

Tags

NGSS.HS-LS3-1

NGSS.HS-LS3-2

Which of the following are sex chromosomes?

• X

• Pairs #1-22

• Y

Which genotype represents a male that has normal vision? (not color blind)

• X^BX^b

• X^BY

• X^bY

• X^BX^B

Tags

NGSS.HS-LS3-1

NGSS.HS-LS3-2

Which of the following genotypes is a female with normal vision? (select all that apply)

• X^BX^b

• X^BX^B

• X^bX^b

• X^BY

Tags

NGSS.HS-LS3-1

NGSS.HS-LS3-2

Are males or females more likely to be carriers for sex-linked traits?

• Males

• Females

• Both

Why can males not be carriers for many sex-linked traits?

• Because males are more affected by diseases

• Because males only have 1 X chromosome and whatever allele it carries is what they are (they can't be heterozygous)

• Because females can overcome diseases regardless of their genes