We humans are mesmerized by melanin, the pigment that gives color to our skin, but almost always for quite the wrong reasons.
Clearly melanin is a handy and fascinating compound, with an intriguing evolutionary history. But because its effects are so visible in our skin, it has for centuries been made to bear an utterly undeserved burden of sociological and political significance. As is detailed elsewhere in this issue, there are far more genetic differences among the people who make up these arbitrary constructs we call races than there are differences between races. It is time to move away from simplistic efforts to explain all our differences in terms of just one molecule and to pay attention to the tens of thousands of other molecules that make up our wondrously complex cells–and selves.
Neuromelanin isn’t obviously related to skin pigment. People with albinism, who have no melanin in their skin, hair, or eyes, have normal amounts of melanin in their brain cells.
As for the real significance of brain melanin, the jury is still out–we have no idea what it does. We do know that a lot of it is found in the substantia nigra (the “black substance”), a darkly colored structure buried deep in the brain that makes dopamine. We also know that melanin- rich cells in the substantia nigra are the ones most likely to be destroyed in people who have Parkinson’s disease, resulting in tremors and rigidity. But whether this preferential destruction is due to some property of the neuromelanin or is the result of some other process that just happens to destroy neuromelanin-rich cells is not yet clear. What is clear is that.