In Fruit Flies, Eye Color Is a Sex Linked Trait. Red Is Dominant to White

Name ______Genetics: X Linked Genes In fruit flies, eye color is a sex linked trait. Red is dominant to white.

1. What are the sexes and eye colors of flies with the following genotypes: X R X r ______X R Y ______X R X R ______X r Y ______

2. What are the genotypes of these flies: white eyed, male ______red eyed female (heterozygous) ______white eyed, female ______red eyed, male ______

3. Show the cross of a white eyed female X r X r with a red-eyed male X R Y .

4. Show a cross between a pure red eyed female and a white eyed male.

What are the genotypes of the parents: ______x ______

How many are: white eyed, male______white eyed, female ______red eyed, male ______red eyed, female ______

5. Show the cross of a red eyed female (heterozygous) and a red eyed male.

What are the genotypes of the parents? ______& ______

How many are: white eyed, male______white eyed, female ______red eyed, male ______red eyed, female ______Hemophilia is a rare inherited bleeding disorder where the blood does not clot normally. Someone with hemophilia may bleed for a longer time following an injury. H = no hemophilia (normal) h = hemophilia (x linked recessive trait)

Fill in the following phenotypes: XHXH = ______XHY = ______XHXh = ______XhY = ______XhXh = ______

6. In humans, hemophilia is a sex linked trait. Show the cross of a man who has hemophilia with a woman who is a carrier.

What is the probability that their children will have the disease? ______

7. A woman who is a carrier marries a normal man. Show the cross. What is the probability that their children will have hemophilia? What sex will a child in the family with hemophilia be?

8. A woman who has hemophilia has a phenotypically normal mother. What are the genotypes of her mother and father?

Mom ______

Dad ______

9. A phenotypically normal woman has phenotypically normal parents. However, she has a hemophiliac brother. a) What are the chances of being a carrier for hemophilia? ______

Color blindness (color vision deficiency) is a condition in which certain colors cannot be distinguished, and is most commonly due to an inherited condition. Red/Green color blindness is the most common form, about 99% of all color blind cases, and causes problems in distinguishing reds and greens. Another color deficiency Blue/Yellow also exists, but is rare. Total color blindness (seeing in only shades of gray) is extremely rare. C = normal vision c = color blind

10. If a normal sighted woman whose father was colorblind marries a color blind man, what is the probability that they will have a son who is colorblind? ______b) What is the probability that they will have a color blind daughter? ______11. What is the probability that a color blind woman who marries a man with normal vision will have a color blind child?

In cats, the calico color pattern has black, orange/red, and white all represented in clear color blocks. The gene for calico (multicolored) cats is codominant. Females that receive a B (Black) and an O (Orange) gene have black and orange splotches on white coats. Males can only be black or orange, but never calico.

Fill out the phenotypes for the following genotypes:

XBXB = ______XBY = ______XBXO = ______XOY = ______XOXO = ______

12. Show the cross of a female calico cat with a black male?

What percentage are black male kittens? ______What percentage are calico female kittens? ______

13. Show the cross of a female black cat, with a male orange cat.

What percentage are calico female? ______What color will all the male kittens be? ______