There is very little of Jōmon history that is conclusive, however, starting in the 1990s, rapid advances in genetic analyses revealed much more than was previously known. It appears that the ancestors of the Jōmon people walked into the Japanese archipelago as much as 38,000 years ago, when great swathes of the earth’s land surface was covered by gargantuan ice sheets, via a land bridge from northeast Asia (modern-day Siberia). This would time their arrival in Japan at about 10,000 years before modern humans are thought to have begun to migrate to North America via the Bering Strait land bridge. It also seems likely that the ancestors of the Jōmon people were following migrating megafauna like woolly mammoths when they crossed the land bridge to Japan. It has also been proposed that the ancestors of the Jōmon people may have followed a southern route into Japan.

Today, the indigenous Ainu of Northern Japan and the Ryukyuan people of Okinawa are the most closely related to the ancient Jōmon people. Furthermore, most modern Japanese share about 9% to 13% of their DNA with the ancient Jōmon people, so there clearly was contact between the Jōmon people and the modern Japanese who arrived from the Asian mainland starting just over 2,000 years ago. As science continues to make advances in the study of DNA, it is certain that we will learn even more about the ancient Jōmon people.