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X-Linked Inheritance

Total questions: 12

Worksheet time: 56mins

Name
Class
Date
1.

Orange or black fur is a single, X-linked, co-dominant trait in cats. Calico cats have white fur with patches of orange and black. Is it true that calico cats can only be female?

a)

Yes, because they have 2 'X' chromosomes, and therefore can have both the orange and black alleles (XO XB)

b)

No, males can be calico because they can have both the alleles for orange and black (XO YB)

c)

Yes because the trait is found on the X chromosome (XOB X)

d)

No, males can be calico because the trait is found on the X chromosome (XOB Y)

2.
What percentage of the offspring will have this recessive disease?
a)
0%
b)
25%
c)
50%
d)
75%
3.

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

a)

fathers pass the allele for colorblindness to their sons only

b)

the allele for colorblindness is located on the Y chromosome

c)

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

d)

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

4.

Colorblindness is a recessive X-linked disorder.

Which genotype represents a male with normal vision?

a)

XN YN

b)

Xn Yn

c)

XN Y

d)

Xn Y

5.
Which of the following genotypes belongs in the red box in the Punnett square?
a)
XBXb
b)
XbXb
c)
XbY
d)
XBY
6.
Which of the following genotypes belongs in the red box in the Punnett square, and what would the genotype be for the trait?
a)
XBX- female heterozygous
b)
XbX- female homozygous recessive
c)
XBX - female homozygous dominant
d)
XbY - male heterozygous recessive
7.
In fruit flies, red eye color (R) is a sex-linked trait that is dominant over white eye color (r).  According to the Punnett square, what percentage of female offspring will have white eyes?
a)
0%
b)
25%
c)
50%
d)
100%
8.

Duchenne muscular dystrophy is a recessive X-linked disorder.

According to the Punnett square, what percentage of offspring will have the disorder?

a)

0%

b)

25%

c)

50%

d)

100%

9.

Hemophilia is a recessive X-linked disorder. According to the Punnett square, which is NOT true?

a)

50% of all offspring will have the disorder

b)

50% of male offspring will not have the disorder

c)

25% of female offsprings will have the disorder

d)

the mother does not have the disorder but is a carrier

10.
What percentage of the female offspring will be carriers for this recessive disease?
a)
0%
b)
50%
c)
100%
d)
25%
11.

Males are more likely to suffer from a sex-linked disease or disorder because...

a)

males are the weaker sex

b)

males have less DNA

c)

males have 1 X chromosome, so the disorder is more likely to be expressed

d)

females are the stronger sex

12.

What chromosome letter pairs are used to represent males and females

a)

XX = female and YY = male

b)

XX = female and XY = male

c)

XX = male and YY = female

d)

XX = male and XY = female