biology/genetics?

Question

I need help with genetics, i am really confused.


In humans, colorblindness is a recessive, sex-linked trait. What is the percentage chance that a child of a woman heterozygous for colorblindness and a man with normal color vision will be colorblind?

and another question that is exactly like that but with the child being a boy....

whats the difference of the childs sex, does it matter?

Answer 1

The female has two X chromosomes, one with the recessive colorblind gene: XC Xc

The male only has one X chromosome, it's normal: XC Y

All female children will be normal, because they recieve a normal X chromosome from dad. Genotypically they would be 50% homoyogous dominant (XC XC) and 50% heterzygous (XC Xc)

Male children have a 50% chance of being colorblind. They get a Y chromosome from dad and one of two X chromosomes from mom. (50% XC Y, 50% Xc Y)

Answer 2

Colorblindness is rare in females as it is a sex linked trait that is carried on the X chromosome. The chances of a girl being colorblind with the above couple as parents is next to none; the boy would be about 25%. If a female receives one x with the trait and one without the dominant (non-colorblind) gene will prevail. If the boy gets the color blind x from his mother he will be colorblind...the y cannot override this combination.

Answer 3

Does it say whether the man is hetero or homozygous?

I could be wrong, because I haven't done genetics in a while. If the man is heterozygous then there's a 75% chance that the child won't be colorblind and a 25% that the child will.

If he's homozygous then it's 100% that he won't.

Dunno about the child being a boy.

Answer 4

The woman with recessive gene for colour blindness can either give a healthy X or a infected X. But those (either X or Y) from father are healthy. So, the chance colour blindness seems to be 50% in the child. But if it is a female child, then she either has no gene for colour blindness or she is a carrier because she receives the healthy X gene from the father no matter she gets healthy or infected one from the mother. But in case of a male child, he is colour blind if he receives infected gene from mother and he is free of it if he receives the healthy one from the mother.

Answer 5

you do no longer say if it is intercourse-appropriate, so we''ll assume it is common Mendelian genetics, then it would be D for dominant, extra suitable digits. And d for the familiar # of digits. Dad might desire to be Dd or DD. mom is dd. little ones might desire to be Dd : dd, 2/4 extra suitable, 2/4 general, for the 1st go. little ones may be all Dd, 4/4 extra suitable for the 2d go. however the daughter is general, dd. So, Dad is Dd. So it is the 1st one, Dd:Dd, the place there's a 50/50 danger.