MC1R intronless gene encodes the receptor protein for melanocyte-stimulating hormone (MSH). The encoded protein, a seven pass transmembrane G protein coupled receptor, controls melanogenesis. Two types of melanin exist: red pheomelanin and black eumelanin. Gene mutations that lead to a loss in function are associated with increased pheomelanin production, which leads to lighter skin and hair color.
The MC1R gene provides instructions for making a protein called the melanocortin 1 receptor. This receptor plays an important role in normal pigmentation. The receptor is primarily located on the surface of melanocytes, which are specialized cells that produce a pigment called melanin. Melanin is the substance that gives skin, hair, and eyes their color. Melanin is also found in the light-sensitive tissue at the back of the eye (the retina), where it plays a role in normal vision.
So, here’s the question posed by people trying to understand their ethnicity.
If I have 3% Melanesian (or Middle Eastern, Indo-Tibetan or fill-in-the blank ethnicity), doesn’t that mean that one of my great-great-great-grandparents was Melanesian?
There are really two answers to this question. (I can hear you groaning!!!)
If the amount is 25% (for example) and not very small amounts, then the answer would be yes, that is very likely what this is telling you. Or maybe it’s telling you that you have two different great-grandparents who have 12.5 each – but those relatives are fairly close in time due to the amount of DNA that came from that region. See, that was easy.
However, the answer changes when we’re down in the very small percentages, below 5%, often in the 1 and 2% range. This answer isn’t nearly as straightforward.