Answers to Quora Questions by Yair Davidiy (20 December 2017, 2 Tevet , 5778)
Will DNA testing prove I have Jewish heritage in my maternal line?
Hopefully others will give you the technical details. Usually commercial DNA testing gives you an option of mtDNA, YDNA, and some form of autosomal (i.e. general) DNA. The first one, mtDNA, is what is passed on from mother to daughter, generation after generation, without (at least in theory) influence from the male side. There is a certain type of mtDNA held by about 60% of Jewish females of the Ashkenazic community. This is similar to that of Tuscany in northern Italy but, in theory, distinguishable from it. This does not mean that whoever has this mtDNA haplogroup had a Jewish ancestress but it raises the chances. There are also other types of mtDNA found among Jews. You can take your results and compare them to the mtDNA of others. This may done on the web or through DNA testing companies. If you find you have similar mtDNA to people who are Jewish or have Jewish names etc you may have clues worth following up on. Nevertheless, DNA findings are not enough in themselves to establish Jewish ancestry.