The same book states:
"DNA evidence shows that millions of people are descended from a single ancestor who travelled across Asia at this time [late 12th / early 13th century A.D.]. It is most likely that this was Genghis Khan himself, who, after centuries in which his descendants have multiplied, is literally the father of Asia."
–"The World: A Family History of Humanity" by Simon Sebag Montefiore