I am Baal Teshuva and my father’s fathers died when my father was very young. My father had no idea where his father was from. I therefore took on my Mother’s family minhagim.
Of course we don’t change minhagim due to DNA testing. The idea is to show that minhagim change and people move around. If not, how could the entire Chasidische velt take on Nusach Sefard?