How is colour blindness inherited?

Question

chromosme number? DOminant? Recessive? Sex linked?

Answer 1

Colour blindness is inherited from the parent's genes. It depends upon the genes determine who a person is.

Answer 2

Colour blindness is X-linked recessive. (ie. the gene is on the X chromosome and you need to have two "affected" chromosomes (except in males) to have the condition).
This is why a lot more men are colour blind than woman. As men only have one X chromosome, if that chromosome has the gene then they will have the condition whereas women have two X chromosomes; so if one of the chromosomes has the gene and the other doesn't then the woman will not be colour blind.

Colour blind gene: Xh, non-colour blind gene: XH

Eg. 1 Mother: Xh Xh (colour blind)
Father: XH Y ('normal')

Offspring: 50% XHXh (f carrier)
50% XhY (m colour blind)

Note how all sons of a colour blind mother will be colour blind and none of the daughters.


Eg. 2 Mother: XH Xh (carrier) Father: Xh Y (colour blind)
Offspring: 25% XHXh (f carrier)
25% XhXh (f colour blind)
25% XHY (m 'normal')
25% XhY (m colour blind)

Answer 3

It is sex linked. Colour blindness is caused by a defective gene on the X chromosome, so men only need oen bad gene to get it, but women need too. If you are the child of a pair with one colourblind partner:
-If you are a girl, you will either be a carrier or have no trace of it.
-If you are a boy, you wil either have the disease or have no trace of it.

Only mutation or having two parents wit the ggene will produce a femal with colour blindness.

Answer 4

a) Only the mother. Females are XX. Males are XY. The colorblindness gene is sex-linked, located on the X-chromosome, so a male need only 1 gene to inherit the trait, but a female needs two of the same gene to inherit. That explains why there are way more colorblind males than females. Hope this helps!

Answer 5

x linked recessive