Color blindness, particularly red-green color blindness, is more common in males than females primarily due to genetic factors linked to the X chromosome. Here's a breakdown of the reasons:
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Genetic Link: The genes responsible for the most common forms of color blindness (such as red-green color blindness) are located on the X chromosome. Males have one X and one Y chromosome (XY), while females have two X chromosomes (XX).
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Inheritance Pattern: If a male inherits an X chromosome with the color blindness gene, he will express the trait because he does not have a second X chromosome that could potentially carry a normal vision gene to compensate. In contrast, a female would need to inherit the color blindness gene from both of her X chromosomes to express the trait. If she has one normal vision gene on one X chromosome, it can mask the effect of the color blindness gene on the other X.
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Frequency: As a result of this inheritance pattern, color blindness occurs in approximately 8-12% of males of Northern European descent, but only about 0.5-1% of females.
This genetic basis is why color blindness is significantly more prevalent in males than in females.