What are the causes of red-green color blindness?

There are two types of light receptors in the human eye - rods and cones.

Rods are very sensitive to light, but don't see color well.

Cones require brighter light to work, but they are used for color vision.

There are three types of cones... one for each primary color.

In red-green color blindness a genetic defect causes the cones that detect green light to be missing or to not work. The result is vision with no green component.

Color Blindness Is Caused By

colour blindness is caused by alleles in sex-linked chromosomes (X) and (Y)

people having colour blindness have homozygous or one recessive alleles. we all know man have XY and woman have XX. for man, Y cannot contain many genes as X, and the gene controlling colour blindness is on X chromosomes. for girls, if she has heterzygous alleles of colour blindness gene, she won't have colour blindness but she is a colour blindness gene carrier.

for boys, if a recessive allele is on his X chromosome, the allele express into colour blindness

i think its due to being a guy and lacking in a part of the chromosome us females have. thus more males are colour-blind.

It is often a sex-linked gene. Heredity.