The X chromosome represents approximately 5% of the total DNA in cells.
Gene examples of chromosome X:
The genes OPN1LW and OPN1MW encodes long-wavelength- and middle-wavelength-sensitive photopigments in the cones (specialized cells for the detection of light and color) of the retina (a light-sensitive tissue that lines the back of the eye). Mutations in these genes cause colour vision deficiency.
The F8 gene carries instructions for the coagulation factor VIII, which is required for normal blood clotting. Defects in this gene results in hemophilia A (blood clots can't form properly in response to injury, leading to excessive bleeding).