Show Notes
Ishiya K et al., PNAS - This episode examines a PNAS study that reports two high-coverage ancient human genomes from mainland Japan (an Initial Jomon >67× and a Middle Yayoi >46×). The genomes enable diploid genotyping, demographic reconstructions, ancestry modeling, and AMY1 copy-number analysis that reshape understanding of Jomon and Yayoi histories. Key terms: ancient DNA, Jomon, Yayoi, AMY1, population history.
Study Highlights:
The authors sequenced two low-contamination, high-coverage genomes from mainland Japan (IY1, Initial Jomon; DO, Middle Yayoi) enabling diploid analyses and CNV inference. Demographic reconstructions show divergent post-LGM trajectories: long-term stability with no expansion in the Jomon lineage and gradual sustained growth in the Yayoi-related ancestral population. Admixture and f-statistics indicate substantial continental Northeast Asian ancestry in the Yayoi individual and genetic continuity between the Yayoi and present-day mainland Japanese. High AMY1 copy numbers (~9–10) in both individuals suggest starch-relevant variation existed before large-scale rice farming.
Conclusion:
High-coverage ancient genomes from mainland Japan reveal contrasting population histories for Jomon and Yayoi lineages and show that elevated AMY1 copy-number variation relevant to starch consumption predates intensive rice agriculture, refining models of Japanese population formation.
Music:
Enjoy the music based on this article at the end of the episode.
Article title:
High-coverage ancient genomes reveal divergent population histories and prehistoric starch-related genetic variation in Japan
First author:
Ishiya K
Journal:
PNAS
DOI:
10.1073/pnas.2606162123
Reference:
Ishiya K., Mizuno F., Gojobori J., Kumagai M., et al. High-coverage ancient genomes reveal divergent population histories and prehistoric starch-related genetic variation in Japan. Proc Natl Acad Sci U S A. 2026;123(30):e2606162123. doi:10.1073/pnas.2606162123
License:
This episode is based on an open-access article published under the Creative Commons Attribution 4.0 International License (CC BY 4.0) – https://creativecommons.org/licenses/by/4.0/
Support:
Base by Base is independent and ad-free — no sponsors, no paywall. If an episode was worth your time, chip in and keep the papers audited and the original songs coming:
❤️ Support monthly: https://buy.stripe.com/cNifZhclVebvagk2JDgEg01
☕ One-time donation: https://donate.stripe.com/7sY4gz71B2sN3RWac5gEg00
More at basebybase.com
On PaperCast Base by Base you'll discover the latest in genomics, functional genomics, structural genomics, and proteomics.
Episode link: https://basebybase.com/episodes/high-coverage-ancient-genomes-japan
QC:
This episode was checked against the original article PDF and publication metadata for the episode release published on 2026-08-06.
QC Scope:
- article metadata and core scientific claims from the narration
- excludes analogies, intro/outro, and music
- transcript coverage: Audited the transcript sections describing (1) sampling of two high-coverage genomes (IY1 and DO), (2) authenticity checks and sequencing depth, (3) demographic inferences (PSMC/SMC++), (4) AMY1 copy-number findings, (5) ancestry and admixture contexts, (6) admixture timing, and (7) the dual-structure model; excluded n
- transcript topics: Two high-coverage mainland Japan genomes (IY1 Jomon, DO Yayoi); Petrous bone sampling and ancient DNA authentication; PSMC/SMC++ demographic inferences post-LGM; AMY1 copy-number variation and starch-diet adaptation; Ancestry and continental admixture in Yayoi vs Jomon; Admixture timing via LD decay and related methods
QC Summary:
- factual score: 10/10
- metadata score: 10/10
- supported core claims: 5
- claims flagged for review: 0
- metadata checks passed: 4
- metadata issues found: 0
Metadata Audited:
- article_doi
- article_title
- article_journal
- license
Factual Items Audited:
- Two high-coverage ancient genomes from mainland Japan were analyzed: IY1 (Initial Jomon) and DO (Middle Yayoi).
- IY1: ~67-fold autosome coverage; DO: ~46-fold autosome coverage.
- AMY1 copy-number is high in both individuals: IY1 ~9 copies; DO ~10 copies.
- Yayoi individual DO shows continental Northeast Asian ancestry; Jomon individual IY1 shows basal East Asian ancestry.
- Admixture between Jomon and Yayoi occurred roughly 65–79 generations ago.
- Present-day Japanese are modeled as a dual-structure mixture of Jomon and Yayoi lineages.
QC result: Pass.
