Spin all you want, but until you read a few books on the subject you aren't even able to present a rational argument. Nor are you worth debating. Its like you were playing a game of chess and you demanded, "King me!"
And you mentioned vitamin D for a reason. It was supposed to support your argument for an "improved" skin color. You have not shown that. But my question was what was the color which was "improved" upon. It seems to me that you imply that lighter came from dark through not so dark. That would imply light is "improved" from dark. What is that "improvement"?
P.S. I don't care what you think you learned. What matters is what and how you argue. The operating word is "improvement" because you supported an statement about an accusation concerning DNA degradation. In fact, DNA is degraded continuously but it is repaired by cellular processes. You know that.