Biology

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If two people with normal vision have a daughter can she be colorblind? I tought that the answer would be no because it is sex linked and the second X in women makes up for the X that is colorblind that she might have but what if they are both carriers of the color blind gene?

Thank you for using the Jiskha Homework Help Forum. Here are some sites on color blindness:

1. http://en.wikipedia.org/wiki/Color_blind

2. http://www.allaboutvision.com/conditions/colordeficiency.htm

3. http://www.agape1.com/color%20vision.htm

Colorblindness is an X-linked gene, a recessive gene on the X chromosome. However, if a man has it, he has no dominant normal color vision gene on the Y chromosome to keep it from being expressed in the phenotype (actual physical traits).

Men cannot be carriers (those who have the trait in their genes but do not express it in their phenotype) for colorblindness. They either lack the colorblind gene or they are colorblind.

A daughter of a carrier mother and a colorblind father can be colorblind. By chance, half of the daughters from this type of union will be colorblind.

I hope this helps a little more. Thanks for asking.

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