Medieval DNA From Russia

Medieval ancient DNA from Eastern Europe is consistent with the historical and linguistic narrative of the peoples who make up the Russian state.

The foundation of the first ancient Rus’ state occurred as a result of the consolidation of diverse communities inhabiting Eastern Europe during the second half of the first millennium CE. Historical sources imply that these communities mostly include East Slavs, whose settlement across a vast territory led to the emergence of the East Slavic/Rus’ culture within the Rus’ state. 

We generated genomic data for 200 medieval individuals from different locations to elucidate the origin and genetic structure of the Rus’ population during the early stages of the state formation. Our findings reveal a genetic continuum predominantly shaped by two key genetic groups: a broad Slavic-related continuity of different genetic subclusters of Rus’ occupying the enormous European Plain area, and a Fenno-Ugrian (Uralic)-related component in the Northern Rus’ region. Importantly, both groups have a shared genetic substrate inherited from preceding ancient Baltic region populations. 

To scale Scandinavian ("Viking") heritage, we traced minor Scandinavian genetic lineages that did not make up the dominating genetic stratum of the early Rus’ state. 

Our study presents the first comprehensive genomic image of the medieval Rus’, highlighting the intricate cultural and genetic interactions between Slavic, Fenno-Ugrian, and other groups that formed the first Rus’ state affecting Europe’s history.

Andreeva et al., Genetic history of Rus’, bioRxiv (December 30, 2025), doi: https://doi.org/10.64898/2025.12.30.695215 (Hat tip to Davidski at Eurogenes).

The Widest Galaxy

The galaxy with the greatest diameter ever observed (IC1101) has a diameter of 520 kiloparsecs (1.7 million light years), and it is still growing. By comparison, our Milky Way galaxy has a diameter of about 100,000 light years (about 31 kiloparsecs).

More On Wide Binaries

A paper claims to see MOND in a reanalysis of wide-binary star data. I'm still on the fence.

Wide binary stars provide natural laboratories for directly probing gravity in the low-acceleration regime, as dark matter inferred from any viable gravity has negligible effects on their internal dynamics. Various recent studies including Bayesian 3D analyses have shown that wide binaries with separations greater than several thousand astronomical units experience MOND-type gravity with a boost factor of γ≈1.3−1.6. However, results claiming preference for, or no deviation from, standard gravity have also been published during the same period, particularly highlighting the roles of data quality control and realistic modeling of multiple-star (i.e., triple and higher-order) systems that host hidden companion stars. 

Here we carefully reexamine the issues of data quality control and modeling multiple-star systems in statistical gravity tests based on sky-projected 2D velocities of wide binary stars. Through extensive tests including the acceleration-plane test, the ṽ -distribution test, and the median-ṽ -profile test (where ṽ is the sky-plane 2D relative velocity normalized by the Newtonian circular velocity between the two stars), we show that proper data quality control or reasonable variation in multiple-star modeling cannot remove the low-acceleration gravitational anomaly but confirms the MOND-type gravitational anomaly, particularly consistent with recent realistic MOND solutions of wide binary orbits. 

We find that studies claiming no evidence for the low-acceleration gravitational anomaly are consequences of bypassed calibration of the fraction of multiple-star systems using the Newtonian-regime data, bias-introduction in data quality control that is not taken into account in gravity tests, or insufficient statistics in the low-acceleration regime.

Kyu-Hyun Chae, Youngsub Yoon, "Revisiting Data Quality Control and Multiple-star Modeling in Wide Binary Gravity Tests: Confirmation of MOND-type Gravitational Anomaly at Low Acceleration" arXiv:2607.14450 (July 16, 2026) (submitted to the AAS journals).