one of the gene present exclusively on the X-chromosomes in humans is concerned with

1. baldness
2. red-green color blindness
3. facial hair/moustaches in males
4. night blindness

Colour blindness, orcolour visiondeficiency, is the inability or decreased ability to seecolour, or perceive colour differences, under normal lighting conditions. Colour blindness affects a significant percentage of the population.There is no actual blindness but there is a deficiency of colour vision. The most usual cause is a fault in the development of one or more sets ofretinalconesthat perceive colour in light and transmit that information to the optic nerve. This type of colour blindness is usually asex-linkedcondition. The genes that produce photo pigments are carried on the X chromosome; if some of these genes are missing or damaged, colour blindness will be expressed in males with a higher probability than in females because males only have one X chromosome (in females, a functional gene on only one of the two X chromosomes is sufficient to yield the needed photo pigments).

Thanks and Regards
Apoorva Arora
IIT Roorkee
askIITians Faculty