My gunslinging ancestor
Ancestry magazine has an article on uses of aliases by ancestors, and my gunslinging judge great-grandfather got a prominent mention. My online tale of him is here. Outlaw Nat Hickman, who became Judge Charles Hardy of Arizona Territory.
UPDATE: same issue has an article on DNA and all that. Studies have shown that over 16 million people have Genghis Kahn's DNA. About 80% of England has Edward III's DNA. I read somewhere that DNA work shows we have twice as many female ancestors as male ones. Throughout history, men took chances. The unsuccessful ones often died. The successful ones averaged two women apiece.
It also has an article on "pedigree collapse." You'd expect a person to have four grandparents, eight great grandparents, etc.. But if cousins marry, at some point their ancestry overlaps and they have common ancestors, so the total count drops. They list one recent king who, due to intermarriage of the royalty, had only half the theoretic number of great great grandparents.