A woman who is a carrier for colorblindness and has five fingers marries a colorblind man with six fingers (his mother had five fingers and the gene for six fingers is dominant). What percent of the kids would you predict to be colorblind and have five fingers?

Accepted Solution

Answer:50% of the kids (all the boys) will have 6 fingers and 50% will be colorblindStep-by-step explanation:Women have two X chromosome: XXMen have one X and one Y chromosome:Colour blindness is a hereditary condition, passed down from your parents. The gene which is responsible for the condition is carried on the X chromosome, reason why many more men are affected than womenc: colorblindness geneWoman carrier of colorblindness: XcX (or XXc)Woman colorblindness: XcXcWoman not carrier of colorblindness gene or not colorblindness: XXMan colorblindness: XcYMan not colorblindness: XYDominant gene show their effect even if the individual only has one copy of the gene (e.g. gene for brown eyes is dominant, therefore you only need one copy of the 'brown eye' gene to have brown eyes (although, with two copies you will still have brown eyes))6: 6 fingers gene (dominant gene)Woman 6 fingers: X6X (or XX6), X6X6Woman 5 fingers: XXMan 6 fingers: X6Y, XY6, X6Y6Man 5 fingers: XYIn this particular case the woman is a carrier for colorblindness ( XcX or XXc) and have 5 fingers (XX)The man is colorblind (XcY) and have 6 fingers (X6Y, XY6, X6Y6) Now we have to look which of the 6 fingers option for the man is the correct one for this particular exercise:If the mother of the man, have 5 fingers (and as 6 fingers is a dominant gene), she must be XX, so he got the 6 finger gene from the father, then he have the Y chromosome with the 6 finger gene and the X chromosome without 6 finger gene. The right option is XY6So let's cruz the woman XcX with the man XcY6The results are XcXc, XXc, XcY6 and XY6XcXc : girl colorblindnessXXc: girl carrier of colorblindness gene XcY6: boy colorblindness and 6 fingersXY6: boy with 6 fingers50% of the kids (all the boys) will have 6 fingers and 50% will be colorblind