When used properly, Principal Component Analysis (PCA) is an extraordinarily powerful tool and one of the best ways to study fine-scale genetic substructures within Europe. The PCA plot below is based on Global25 data and focuses on the genetic relationship between Wielbark Goths and Medieval Poles, including from the Viking Age, in the context of present-day European genetic variation. I'd ..read more

Years of blogging about population genetics has seriously eroded my faith in the peer review process. During the past decade I've witnessed an inordinate amount of crap published in basically all of the major science journals. Often the work is misguided in some way, sometimes even quite strange, and occasionally outright wrong. Back in 2014, a team of scientists from the UK published a paper ..read more

I've just been sent a fascinating thesis on the mtDNA of Iron Age and Medieval samples from Poland. It suggests direct genetic continuity between Iron Age samples belonging to the Przeworsk and Wielbark Cultures, of what is now West and Central Poland, and present-day Poles. Here's the English summary, and a map of the sites under study: For many years the origin of the Slavs has been the ..read more

This is a continuation of my ChromoPainter analysis of Europeans from north of the Pyrenees, Alps and Balkans (see here). To obtain the most accurate results possible on my laptop, I increased the burn-ins and iterations in fineSTRUCTURE to 500K each (5 hour run in all, which is all I'm willing to put this machine through). The end product looks very similar to my initial analysis, in which I ..read more

I have some preliminary results from a new intra-North Euro cluster analysis, using a cutting edge tool called ChromoPainter. More than 400 samples and 270K SNPs were tested, in linkage mode, and then the output processed in fineSTRUCTURE at 200K burn-ins and iterations. Like I say, the results should be treated as preliminary, but they already look better than any other cluster analysis I've ..read more

Case in point, here's a quote from a recent paper at the Journal of Human Genetics (emphasis is mine): The Mordovian and Csango samples have a moderate to slight orientation toward the Central-Asian and Siberian Turkic groups. This could suggest the more significant East Eurasian or Turkic ancestry of these populations, which should be further investigated. German samples are inhomogeneous, and ..read more

A new preprint featuring hundreds of Viking Age genomes has appeared at bioRxiv [LINK]. Titled Population genomics of the Viking world, it looks like a solid effort overall, although I'm skeptical about its conclusions. I might elaborate on that in the comments below, but I'll have a lot more to say on the topic if and when I get to check out the ancient genomes with my own tools. Details about ..read more