According to GeneBase I carry yDNA D(M174), which is almost completely Japanese. I'm a blue eyed, fair skinned, Caucasoid. My closest match, according to GeneBase is a Japanese man who carries yDNA R1a, and we shared a common ancestor, at the most, 150generations ago (500 years ago, is that correct?). How can I have yDNA D having regard to my physical characteristics, and an a match who shares a different yDNA Hpg?