Anywhere but the steppe

Last week Scientific Reports put out a paper by Sarno et al. on the population history of Sicily and South Italy. I didn't blog about it at the time because I felt that it was generally a weak effort and not worth advertising. But people keep bringing it up in the comments section, so here goes.

If you download the PDF and do a search for "Africa", you'll see that the only time it comes up is in the bibliography. "Maghreb" doesn't come up at all.

Can anyone explain this? I can't. If you're doing a paper on the population history of Sicily and South Italy and you don't take a close look at the fairly recent North African admixture there, then at best you're naive and confused.

Also, the authors try to enter the Proto-Indo-European (PIE) homeland debate. They basically argue that Indo-European (IE) languages could not have arrived in Southeastern Europe from the Pontic-Caspian steppe because modern-day Southeastern Europeans overall don't pack much Bronze Age steppe admixture. They also claim that based on their admixture dating efforts (which may or may not be accurate) the steppe ancestry by and large arrived in the east Mediterranean during the early Middle Ages with Slavic migrations. Thus, they suggest that a better PIE homeland alternative to the Pontic-Caspian steppe might be West Asia.

These are very weak arguments for a number of important reasons. For instance, language change can happen without massive migrations from afar. Case in point: the Etruscans were a sizable non-IE speaking population in Southeastern Europe until historic times, and discarded their Etruscan language in favor of the IE Latin by being subsumed into the Roman Empire. Indeed, Southeastern Europe has been a bit of a hotspot for this type of thing; Razib has a little more on that and the admixture dating here.

Also worth positing is the likely scenario in which much of the Bronze Age steppe ancestry in Southeastern Europe has been diluted by more recent admixture from the Near East and North Africa. It's hard to say for sure to what extent without direct evidence from ancient DNA, but this is something that should have been considered in the paper.

I won't be blogging much from now on about population history papers based on modern-day samples, because such papers aren't usually worth blogging about.

Reference...

Sarno et al., Ancient and recent admixture layers in Sicily and Southern Italy trace multiple migration routes along the Mediterranean, Scientific Reports 7, Article number: 1984, (2017), doi:10.1038/s41598-017-01802-4

See also...

Italians are interesting people (Raveane et al. 2018 preprint)

Bronze Age Sicilian vs modern-day Sicilians

Late PIE ground zero now obvious; location of PIE homeland still uncertain, but...