Historians dismiss the claim that Adolf Hitler has a Jewish ancestry.
However, let us discuss, how the claim came to be. It all started with Hitler's grandmother, Maria Anna Schicklgruber. Maria worked as a housekeeper to a Jewish family. Hitler's father, Alois Hitler, was an illegitimate son of Maria Anna. Speculations were that Alois was an illegitimate son of Anna to one of the male members of the Jewish household, Leopold Frankenberger. However, no records of such person was to be found during the time her grandmother worked as a housekeeper in the Jewish family, leading to the dismisal of the claim.
In 2010, however, a scientific evidence to Hitler's Jewish ancestry was discovered in the form of DNA markers -- a chromosome called Haplogroup E1b1b1 which is very rare in western Europe and common only to certain groups including Ashkenazi and Sephardic Jews. The DNA test, hence, reveal that Hitler 'might have' a Jewish and African ancestry.