Turner syndrome can result from sex chromosome nondisjunctio

Turner syndrome can result from sex chromosome non-disjunction in the germ line of either parent. If an individual with Turner syndrome is red-green color-blind and both parents have normal vision, in which parent did the non-disjunction most likely occur and why?

Solution

The Nondisjunction(Aa) occurrs in the mother for the color-blind child .This is because the nondisjunction in the mother means either 0 or xx from mom while there is an x from dad so that it can lead x0).

As a result the only possible way to get xo (Turner\'s) is by getting 0 from mom and also x from dad=> colorblind