Hi Art, Wow, I had no idea that there is some genetic basis for this weirdness in seeing color, I also didn't know that there were different types, learn something everyday here on the list! Regards, Chip Louie > > > There is a huge distinction between color blindness and what Chip was > referring to, which is 1/10th of 1% of the population which has what > might be called super color perception. > > > Although you obviously know a lot about digital capture sensors, and I'd > love for you to give me a good explanation, as I requested in a prior > posting, you should keep away from genetics... (I was a premedical > student in University and emphasized genetics) As you can see from the > explanation I wrote in this newsgroup in August, you've got it backwards. > > About Color Blindness: > > There are a number of different types of color blindness, or color > deficiency, a preferred term. (Daltonism is the red-green variety, the > most common type) Each has specific (and different) organic causes, > which are genetic in origin, and are sex-linked, in this case, the genes > for the condition are carried on the X chromosome, making males more > vulnerable to it, since they only have one X chromosome, and therefore > it cannot me masked by a dominant gene if their X chromosome carries the > color deficiency gene. Since females have two X chromosomes, if either > is a dominant "normal" gene for color perception the color deficiency > gene is masked. All color deficient males pass on that gene to their > female offspring since it is on their X chromosome, which may or may not > be masked depending upon if the X chromosome from the woman's side has > the color deficiency gene or not. > > A woman who manifests color deficiency herself (which means both her X > chromosomes carry the gene) can only produce color deficient sons. If > she carries the gene but it is masked by a "normal" gene on her other X > chromosome, approximately half of her sons will manifest color > deficiency. Female offspring possibilities get more complex and depend > upon both the male and female parents. However, no female offspring can > manifest color deficiency unless the male in the pair has it, even if > the female of the pair carries the color deficiency gene on one of her X > chromosomes or actually manifests color deficiency. > > So much for Genetics 101. > > > Kennedy McEwen wrote: > > > In article <FIEDJBDDEKPHGJMLCCCLMEDHCKAA.chip@thelouie.org>, Chip Louie > > <chip@thelouie.org> writes > > > >> > >> Hi Art, > >> > >> There is a pretty large range of what people can perceive in terms of > >> color. > > > > > > <snip> > > > >> Also generally women have about > >> twice the chance to be able to see and reliably make these > distinctions. > > > > > > The gene for colour blindness is carried on the Y chromosome - and so > > passes down the male line of the population, not the female line. > > > > > - > Turn off HTML mail features. Keep quoted material short. Use accurate > subject lines. http://www.leben.com/lists for list instructions. > - Turn off HTML mail features. Keep quoted material short. Use accurate subject lines. http://www.leben.com/lists for list instructions.