Download Sex Linked Genes cp

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Sex Linked Genes
All of the traits below are sex linked unless stated otherwise. Be sure to show all your work and Punnett squares for these
problems in the spaces provided. Sex linked genes are usually carried on the X chromosome. Females have two X
chromosomes (XX), males have only one X chromosome (XY).
1.
What percentage of human offspring receive an X chromosome from their mother in the egg?
2.
What percentage of human offspring receive a X chromosome from their father?
3.
What percentage of human offspring receive a Y chromosome from their father?
4.
What is different between the X and the Y chromosome?
5.
What chromosome are most sex-linked genes carried on?
6.
Two normal visioned parents produce a color-blind son. What are the genotypes of the parents?
7.
Can a colorblind(recessive) man give the gene to his son? Explain why or why not.
8.
Can a colorblind man give the gene to his daughter? Explain your answer?
9.
A cats yellow color is due to a dominant gene, B, and black color to a recessive gene, b. These genes are sex linked genes.
When the heterozgyous condition, Bb, appears, the cats are called tortoise-shell, mixture of yellow and black. What kind
of offspring would we expect from the cross between a black male and a yellow female?
10. What would be the genotypes and phenotypes of all the kittens with a cross between a Tortoise-shell female and a yellow
male?
11. Could you ever have a male tortoise-shell cat? Explain why or why not
12. Hemophilia is a recessive, sex linked gene. If a hemophilic woman and a nonhemophilic man have two boys and two
girls, will any of the children be hemophilic?
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13. If a hemophilic man and a homozygous nonhemophilic woman have two boys and two girls, will any of the children
be hemophilic?
14. Muscular Dystrophy is a sex-linked gene. If a homozygous normal woman marries a normal man, but the man’s father
had Muscular dystrophy, what are the chances they could have a girl or a boy with muscular dystrophy?
15. Ichythyoisis hystrix gravier (a greatly thickened bumpy condition of the skin) is a rare human abnormality, but in the
families in which it occurs, it always occurs in males and is transmitted from the father to all of his sons. Unaffected
females never transmit the gene for this condition. What explanation can you suggest for this curious and unusual type of
inheritance.
16. A husband and wife take their two kids to the doctors for a regular checkup. While there, the doctor discovers something
unusual. The girl is colorblind, but the brother has normal vision. What does the doctor conclude that the kids genotype
would be?
17. What does the doctor also conclude the parents’ genotypes and phenotypes are?
18. A man has a genetic disorder and his wife has no known history of the disease. She is assumed to be homozygous. The
disorder is known to be dominant, but it is unknown if it is autosomal or sex-linked. The man and his wife have 4
children, 2 boys and 2 girls. One of the girls and one of the boys gets the disorder. Is the disease sex-linked? Explain
your answer.