How much more different variations us could have without Toba?
http://en.wikipedia.org/wiki/Chromatophores
We mammals have only one type of pigmented cells: Melanocytes, which produce all skin and hair colours abvaible. We lost the other pigmented cells way early in evolution, as Zirantun said. A larger variation is possible but only in the range of mammal colours... natural greens and blues are out without genetic engineering...
http://en.wikipedia.org/wiki/Chromatophores
We mammals have only one type of pigmented cells: Melanocytes, which produce all skin and hair colours abvaible. We lost the other pigmented cells way early in evolution, as Zirantun said. A larger variation is possible but only in the range of mammal colours... natural greens and blues are out without genetic engineering...
So those monkey evolved the cells to these blue colors ?
http://en.wikipedia.org/wiki/Snub-nosed_monkey
http://en.wikipedia.org/wiki/Cercopithecus_lomamiensis
http://en.wikipedia.org/wiki/Mandrill
really don't know a lot about genetics, but if those sepcies of monkey got blue pigmentation (or if it is not due to chromatophores), it could maybe happen in humans too (even if it would change a lot of things).
Also note that all colors are not the results of chromatophore, for example frog bright colors results from nanostructuration of their skin IIRC.