In humans, color blindness is caused by a recessive gene (c) localized on the X chromosome and normal
In humans, color blindness is caused by a recessive gene (c) localized on the X chromosome and normal color discrimination is the dominant gene (C) 1) a color blind man marries a carrier of the color blindness gene. Determine the probability of birth in marriage a) a normal son b) daughters with light blindness
Let’s designate the chromosome in which the gene that causes the development of color blindness is located as Xc, then the chromosome that transmits the gene for normal color discrimination to the offspring will be XC.
A man who, according to the condition of the problem, is color blind – XcY, he produces spermatozoa Xc and Y.
A woman who is a carrier of the gene for color blindness will normally distinguish colors and her genotype will look like this: XСXс. The eggs produced by it will be XC and Xc.
All possible variants of the offspring of this pair:
boys with color blindness (XcY) – 25%;
boys with color vision norm (XСY) – 25%;
girls with color vision norm (XСXс) – 25%;
girls suffering from color blindness (XcXc) – 25%.
Answer: a). 25%; b). 25%.