Understanding the Inheritance of Color Blindness

In summary, color blindness, specifically the most common form of red/green color blindness, occurs in 7% of males and only 0.4% of females. This is because men only need to inherit the gene from their mother, while women need to inherit it from both parents. This makes it less likely for females to have color blindness, with an expected 3.5% of females having it. However, when considering the probability of inheriting two color blindness genes, the chances for both males and females are equally low (0.07 * 0.07 = 0.0049 or about 0.4%). It is also worth noting that the gene is located on the X chromosome, making it more likely
  • #1
Nim
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I read that the most common form of color blindess (red/green), occurs in 7% of males, but only in .4% of females.

Men just have to get the gene from their mother to have color blindess. But women have to get it from their father also. So shouldn't that make it only half as likely for females to be color blind? Shouldn't 3.5% of females have color blindess?
 
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  • #2
Nope.

Consider a similar situation:

What are your odds of rolling a "1" on a single die? (1/6)
What are your odds of rolling two "1"s on two dice? (1/36)

In order to find the probability that a women gets two color-blindness genes, you have to multiply the problabilities of getting each individual color-blindness gene.

You'll note that 0.07 * 0.07 = 0.0049, which is about .4%.

(However, for completeness's sake, I don't think that both genes have to have the same probability of occurring in this case)
 
  • #3
The colour blindness gene is on the sex chrosome X. Therefore male only carry one X (it is from the mother) and absent from the Y. Therefore as soon as the gene is not functional, the person will have colour blindness. The gene is also dominant that female carry two XX and require both gene to be not functional for colour blindness.

Hukyl gave a good example of stats.
 

1. What is color blindness?

Color blindness, also known as color vision deficiency, is a condition where a person is unable to distinguish certain colors or perceive colors in the same way as others. This is typically due to a genetic mutation that affects the cone cells in the retina, which are responsible for color perception.

2. How common is color blindness?

Color blindness affects approximately 1 in 12 men and 1 in 200 women worldwide. This means that it is more prevalent in males, as the gene responsible for color vision deficiency is located on the X chromosome.

3. What are the different types of color blindness?

The most common types of color blindness are protanopia (inability to see red), deuteranopia (inability to see green), and tritanopia (inability to see blue). There are also other types that affect the ability to see a specific range of colors or cause a complete absence of color vision.

4. Can color blindness be treated?

Currently, there is no cure for color blindness. However, there are some specialized lenses and glasses that can help individuals with color vision deficiency to better distinguish colors. These do not provide a full cure, but can improve color perception in some cases.

5. How does color blindness impact daily life?

Color blindness can make it difficult to perform certain tasks that require the ability to distinguish colors accurately, such as driving, cooking, or choosing clothing. It can also cause challenges in educational and occupational settings, as some professions may require the ability to see colors correctly.

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