The evolving Japanese: the dual structure hypothesis at 30

Area of Science:

• Anthropology
• Population Genetics
• Bioarchaeology

Background:

• The population history of Japan is a long-standing anthropological enigma.
• Kazurō Hanihara's 1991 dual structure hypothesis proposed modern Japanese are an admixture of Neolithic and Bronze Age Korean migrants.
• This hypothesis emerged from a growing consensus in the 1980s.

Purpose of the Study:

• To critically evaluate Hanihara's dual structure hypothesis using recent multidisciplinary research.
• To assess the validity of the hypothesis's core assumptions after three decades.
• To identify areas needing further investigation in Japanese population studies.

Main Methods:

• Review of recent findings in biological anthropology.
• Analysis of new research in historical linguistics.
• Integration of updated archaeological evidence.

Main Results:

• Recent research supports the major assumptions of Hanihara's dual structure hypothesis.
• New findings necessitate a re-evaluation of specific aspects of the model.
• Key areas for future research have been identified.

Conclusions:

• The dual structure hypothesis remains a robust framework for understanding Japanese population history.
• Ongoing research highlights the complexity of population admixture.
• Further investigation, particularly in ancient DNA and archaeology, is crucial for a comprehensive understanding.