This may be old news to those of you who follow developments around DNA, but I first heard the story this weekend when I happened to catch the re-broadcast of a Radiolab episode on NPR. A genetic study disclosed that about one in 200 living men carry the same Y chromosome, meaning they descend from the same ancestor - which was likely Genghis Khan. Genghis Khan (1162-1227) was a Mongol Emperor known for his brutality. He conquered nearly 12 million miles of Eurasia, from the Pacific coast of China and west to Uzbekistan. He may have killed as many as 40 million people. Along the way he had many wives, not to mention his penchant for pillaging and raping in the conquered areas. He probably had hundreds of children.

After Khan's death, his sons continued to expand the Mongol Empire into Europe and had many children of their own. Today, 16 million men living in the boundaries of the old Mongol Empire share this same genetic marker. To prove Genghis Khan was their common ancestor would require a sample of his DNA, but how and where Khan died is a giant mystery. One story says he expired from injuries after falling from a horse. In any case, those he left behind took great pains to keep his grave a secret.

Other kings, including the royal family of Tara, passed their genetic material to many descendants. The O'Neills ruled Ireland from 956 to the early 1600s. Tradition has their common ancestor as a fifth-century warrior known as Niall of the Nine Hostages. O'Neill means grandson of Niall. Y-DNA testing suggests that Niall contributed his genetic marker (M222 sub-clade) to one in five men living in northwestern Ireland today. Like Khan, none of Niall's DNA is available for testing, but the prevalence of the O'Neill surname with  the M222 pattern seems to point to the connection. One should definitely NOT conclude that Genghis Khan or Niall of the Nine Hostages carried "superman" genes. One writer suggests "they were in the right place at the right time with the right personal qualities to become kings." It was a situation of historical selection as opposed to natural selection.  The offspring of powerful men were likely seen as more valuable than other children and as a consequence received better treatment and nutrition. They survived to spawn another generation.