3.
Show the cross of a white eyed female
X
r
X r
with a red-eyed
male X
R
Y .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:
___________& _______________
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 ____
6. In humans, hemophilia is a sex linked trait. Females can be normal, carriers, or have the disease. Males will either have the disease or not (but they won’t ever be carriers)
|
|
|
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 marries a normal man. How many of their children will have hemophilia, and what is their sex?
9. In
cats, the gene for calico (multicolored) cats is codominant. Females that
receive a B and an R gene have black and oRange splotches on white coats. Males
can only be black or orange, but never calico.
Here’s what a calico female’s genotype would look like.
X
B
X R
Show the cross of a female calico cat with a black male?
What percentage of the kittens will be black and male? _________
What percentage of the kittens will be calico and male? _________
What percentage of the kittens will be calico and female? _________
10. Show the cross of a female black cat, with a male orange cat.
What percentage of the kittens will be
calico and female? _____
What color will all the male cats be? ______
=
female, normal
=
female, carrier
=
female, hemophiliac
=
male, normal
=
male, hemophiliac