Prehistoric HBV in the Japanese Archipelago

FUKASAWA Makusu*, KANZAWA‑KIRIYAMA Hideaki, KAWAI Yosuke, TANAKA Tomohisa, MORIISHI Kohji, OKUDA Shujiro, and ADACHI Noboru

The Jōmon people were hunter‑gatherers who prospered in the Japanese archipelago for over 10,000 years before largely disappearing, leaving only faint genetic traces in modern‑day Japanese populations. Since much remains enigmatic regarding the dispersal of early Homo sapiens across East Asia, Southeast Asia, and Oceania during the Late Pleistocene, the homeland of the Jōmon people has remained uncertain and has often been tentatively assumed to be Southeast Asia. Analysis of Hepatitis B virus (HBV) obtained from Jōmon individuals indicates similarity to strains found in gibbons and orangutans in Southeast Asia, as well as evidence of recombination with a genotype specific to Australian Aboriginal populations. The results of this viral analysis suggest the possibility of interbreeding, interaction, or shared ancestral groups among early human populations. These findings provide new insights into prehistoric human mobility and biological interaction networks across the Asia-Pacific region.