Weird Results From Colorblind Test

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I've passed every color blind test I ever did except there was one with different colored squares where I got one wrong. I sometimes think certain shades of green are blue but others insist to me that they are green. They look blue to me.

I have a dresser that I think is blue but others tell me it's green. In my old apartment I thought my bedroom walls were blue and others told me it was green.

Last edited by hanyo on 11 Mar 2012, 1:57 pm, edited 1 time in total.

The blue-yellow color blindness is extremely rare. Not distinguishing blue from purple can be a sign of problems with seeing red. I have it a bit, my father is red-green colorblind and I think for something like random inactivation of the x chromosome http://en.wikipedia.org/wiki/X-inactivation - like in tortoiseshell cats - I don't see purple that well. This is just a theory, though.

Some shades of blue/green seem to be heavily debated by everyone. In a lot of languages the words for blue and green are the same.

Color blindness is almost always hereditary (there is an aquired rare type). My brother, my uncles and me are all color blind. Males born to a woman who carries the genes will be color blind but females just carry it to their offspring and usually don't show it. In other words, my son is not color blind but my daughter will carry it to her sons.

The type i have is protanomaly which means reds do not have the depth and brightness compared to normal vision. In practical terms, I can see a red ribbon but if you put it in a green tree, it will be very difficult for me to find. And of coarse I fail every color blind test I have ever been given.

No, a female carrier has two X chromosomes. If she is just a carrier (and not affected), then only one of her X chromosomes carries the colorblindness gene. Therefore, her sons are not definitely going to be colorblind, but there is a 50% chance.

Carrier female and unaffected male:
Female: XX + Male: XY

Possible offspring:
XX (unaffected, non-carrier female)
XX (unaffected, carrier female)
XY (unaffected male)
XY (affected male)

If the father is affected but the mother is neither affected nor a carrier, there is a 0% chance that any of their children will be affected. However, all of their daughters will be carriers:
Female: XX + Male: XY

Possible offspring:
XX (unaffected, carrier female)
XX (unaffected, carrier female)
XY (unaffected male)
XY (unaffected male)

But if the mother is a carrier and the father is affected, there will be a 50% chance that any of their children (whether male or female) will be affects:
Female: XX + Male: XY

Possible offspring:
XX (unaffected, carrier female)
XX (affected female)
XY (unaffected male)
XY (affected male)

And, needless to say, if both parents are affected, all children will be affected.
Aren't genetics fascinating?

Nobody has tossed out the term and it's bothering me, so here. X-linked recessive is what this sort of gene is called.



I feel better now.

Yeah, you are right- I do remember that from my biology class. So my correction is this: in my immediate family, it is observed in two generations that 100% of males are color blind.