Question: My Dads colour blind why are more mails colour blind then Females?

Jess Wade answered on 17 Jun 2015:

Hi Football fred!
Good question. This is actually a biologist question, but I’m happy to take it as my parent’s are both doctors. My brother’s best friend is colour blind- sometimes he has some pretty funny coloured shoes. Saying blind is actually not true- of course they can see colours, but just not very well. What kind of colours can your dad not see? Mostly it’s things like green and red.
We generally inherit colour blindness from our parents. The genes that make up our DNA contain little scientific codes that tell our bodies everything about us and our parents.
In our eyes, there are two kinds of cells- rod cell and cone cells. rod cells are sensitive to light, but not colour sensitive, and cone cells let us see objects in detail, and see the colours. There are different cone cells for red, blue and green light. We mix together all of the messages from each cone cell to make all the other colours. The genes that tell the red and green cone cells to not work very well are all on something called the X chromosome. Women have two X chromosomes, and men only have one. So if one of the girls is messed up and has the bad genes, then the other one will be able to cope and sends the healthy red and green cones. If the man only has one X chromosome and that is messed up, then he can’t see red or green.
It’s kind of like if your dad’s sister had two sandwiches and your dad only hand one. If your dad’s one sandwich is attacked by ants, he can’t eat it. If your dad’s sister’s sandwich is attacked by ants, she still has another one. So because the girls have a spare set of healthy cones, they don’t go colour blind so much.