1. SEX-LINKED GENES

2. a. Genes that are carried on the sex chromosomes (X & Y) are called sex-linked genes

3. b. the traits they control are called sex-linked traits

4. c. there are both dominant and recessive alleles for sex-linked genes

5. d. sex-linked traits show up much more often in a male because males do not have a matching X chromosome to mask a recessive allele

6. e. When a recessive allele is present in a male it will be expressed

7. f. red-green colorblindness is a sex-linked trait

8. g. Hemophilia (the bleeder’s disease) is also a sex-linked trait

9. h. A person who has an allele for the trait but does not show the trait is said to be a carrier

10. i. Sex-linked traits are passed from mother to son and father to daughter

11. Write the genotypes for the following: phenotypes of red-green colorblindness. Normal male normal female carrying no colorblind alleles colorblind male normal female carrying the colorblind allele colorblind female

12. Write the phenotypes for the following genotypes: XH Xh XH xH XH Y0 Xh Y0

13. A woman who is a carrier for hemophilia marries a man with hemophilia
A woman who is a carrier for hemophilia marries a man with hemophilia. Could any of their children have hemophilia? If so, would the child be male or female?

14. A woman who is heterozygous for hemophilia marries a normal male
A woman who is heterozygous for hemophilia marries a normal male. What are the possible phenotypes of their children?

15. A colorblind man marries a female who is a carrier for colorblindness
A colorblind man marries a female who is a carrier for colorblindness. What is the probability that they will have a child who is colorblind?

16. A colorblind male marries a female who is not colorblind (homozygous)
A colorblind male marries a female who is not colorblind (homozygous). What are the possible phenotypes of their children?