Why is colorblindness more common in males?

Answer 1

It's because it's, what we call, a "sex-linked disorder." You see, men have "xy" chromosomes, and women have "xx" chromosomes. In a sex-linked disorder, all "x" chromosomes in either of the genes have to be affected. if you see an affected x chromosome, it would look something like this "xa". The "y" chromosomes don't become affected, I don't think. Women who have only one x chromosome affected are called "carriers," meaning they aren't affected by the disorder, but they carry it in their genes and can pass it on to their offspring. They don't ALWAYS pass on to the child, but it CAN happen. So why is it easier for men to become colorblind? They have less x chromosomes. If you need more help understanding how that works, Google "Colorblindness and punnet square." The Punnet Square is very important to add to your research! if you're curious.

Answer 2

The vast majority of color blind cases are hereditary- present at birth. The gene for this is carried in the X chromosome. Since males have X-Y pairing and females have X-X. It is typically passed by their mothers. Check out www.toledo-bend.com/colorblind/about CB.html

Some 10 million American men-fully 7 percent of the male population-either cannot distinguish red from green, or see red and green differently from most people. This is the commonest form of colorblindness but it affects only .4 percent of women. The fact that color blindness is so much more prevalent among men implies that, like hemophilia, it is carried on the X chromosome, of which men have only one copy. (As in hemophilia, women are protected because they have two X chromosomes; a normal gene on one chromosome can often make up for a defective gene on the other.) Wald and others had found that in color-blind men, the green or red cones worked improperly or not at all. Wald suggested that the genes for the red and green receptors were altered in these men. He also thought that these genes must lie near each other on the X chromosome. This tandem arrangement-which Nathans confirmed-probably results from the duplication of a DNA fragment in primates that occurred some 40 million years ago.

The primates of South America, which broke from the continent of Africa at about that time, possess only a single functional copy of a red or green gene, much like color-blind men. But in Old World primates-the monkeys and apes of Africa and the ancestors of humans-a primordial red-green gene must have duplicated and then diverged slightly in sequence, leading to separate receptors of the red and green type.

Answer 3

Colorblindness is not impossible in women. The gene is on the X chromosome. Males only have one X chromosome and though it may seem ironic that they have a better chance of being colorblind, they have a greater chance of ending up with the X chromosome containing the defective gene.

Answer 4

One cause of colorblindness is genetic. Usually, who suffered from hereditary color vision defect have red-green color vision defect. Color vision defect is inheritance and lie at sex linked which is x-linked recessive. Because of that ,male (xy) having color vision defect than females (xx). Females only as carrier if both their parents not color vision defect . That why color vision defect more common in males.

Answer 5

Because the gene that causes it is located on the "X" chromosome that men have only have one of; women have two and since it is recessive one bad X chromosome is all it takes to cause colorblindness in men but a woman would have to inherit a defective X from BOTH parents to be colorblind. If a man is colorblind and his father isn't, he inherited a bad X from his mother even if she also has normal vision. If a woman who carries a single recessive colorblindness gene marries a man who is colorblind, all of their sons and half their daughters will also be colorblind.

Answer 6

The Color Blind Trait is an abnormality in the X chromosome. Sex is determined by the X and Y chromosomes Males have an X chromosome and a Y chromosome while Females have two X chromosomes and no Y chromosomes. Since the X chromosome carry's the Color Blind Trait a colorblind male and colorblind female would produce off-spring that would be 100 % colorblind, while a colorblind male and a female that carries the Colorblind Trait will produce females that will carry the color blind trait or be colorblind and a male has a 50% chance to be colorblind. If a non-colorblind male mates with a colorblind female there will be no chance of producing colorblind females but they will always produce carrier females and they will always produce colorblind males. If a colorblind male mates with a female that is not a carrier or colorblind there is a 100% chance that the females produce will be carriers and no chance that the males will be colorblind.

To answer the question... it's all in the genetics and males must have a mother that is a carrier or colorblind to be colorblind in the first place because men do not inherit the X chromosome from their father.

Answer 7

Because Males have only one X chromosome while the Females have two XX chromosomes

Answer 8

It's tied to a genetic mutation carried by the male chromosome.