Download Sex-Linked Traits

Sex-Linked Traits
1. What makes something a sex-linked trait instead of just a regular trait.
2. Are males or females more susceptible (likely to be affected) to sex-linked diseases? Explain.
3. Hemophilia is a sex-linked trait found on the X chromosome. To get this disease, a person must
have a recessive copy of the gene (h) on every X chromosome. Predict the genotypic and
phenotypic probabilities of the offspring if a woman who was a carrier for the disease had a
baby with a man who had the disease.
Genotype of one parent: _______
Genotype of other parent: ______
GENOTYPE: ________________________________________________________________________
PHENOTYPE: _______________________________________________________________________
4. Predict the genotypic and phenotypic probabilities of the offspring if a woman who is
heterozygous (a carrier) for hemophilia marries a normal man:
Genotype of one parent: _______
Genotype of other parent: ______
GENOTYPE: ________________________________________________________________________
PHENOTYPE: _______________________________________________________________________
5. Baldness is also a sex-linked trait found on the X chromosome. To become bald, a person must
have a recessive copy of the gene (b) on every X chromosome. Predict the genotypic and
phenotypic probabilities of the offspring if a woman who has no history of baldness in her
family (B) had a baby with a man who was bald.
.
Genotype of one parent: _______
Genotype of other parent: ______
GENOTYPE: ________________________________________________________________________
PHENOTYPE: _______________________________________________________________________
6. Baldness is a sex-linked trait. What parental genotypes could produce a bald woman? *use B =
normal hair, and b = bald Explain.
7. In humans colorblindness (b) is an example of a sex-linked recessive trait. In this
problem, a male with colorblindness marries a female who is not colorblind but carries the
(b) allele.
Using a Punnett square, determine the genotypic and phenotypic probabilities for their
potential offspring.
Genotype of one parent: _______
Genotype of other parent: ______
GENOTYPE: ________________________________________________________________________
PHENOTYPE: _______________________________________________________________________
8. A male with colorblindness marries a female who is colorblind.
Using a Punnett square, determine the genotypic and phenotypic probabilities for their
potential offspring.
Genotype of one parent: _______
Genotype of other parent: ______
GENOTYPE: ________________________________________________________________________
PHENOTYPE: _______________________________________________________________________
9. Can a color blind female have a son that has normal vision? Color blindness is caused by a sexlinked recessive allele. *use B = normal vision and b = color blind Explain.