n humans, colour blindness is due to an “X” linked recessive trait we shall represent with the symbols Xn. Females that carry a hidden recessive gene for colour blindness in the heterozygous condition are called “CARRIERS”
Show two different crosses that would result in possible colorblind daughters.
The first possible cross is between a color blind man and a color blind carrier woman.Therefore, the color blind chromosome will be shown as XN in a man ,since they carries one X. The X will carry the color blind gene. A woman has two XX chromosomes she can be carrier or color blind. The Recessive trait in a woman will be XXn. The following illustration shows the crossing between a color blind man and color blind carrier woman.
XNXn- Color blind daughter
XNX- daughter color blind gene carrier
The second possible cross is between a color blind husband and a color blind woman .In this case all the daughters will be color blind.