The Boscombe Bowmen

I'm thinking that the Boscombe Bowmen site in Wiltshire, southern England, might be a valuable case study of how the Bell Beaker population, and thus also the present-day western European gene pool, came to be.

Dated to 2500–2140 BCE, this isn't an especially early Bell Beaker grave, but its inventory is intriguing. It includes seven All-Over-Cord (AOC) beakers and one Cord-Zoned-Maritime (CZM) beaker.

Maritime beakers are quintessential Bell Beaker gear, and they're named as such because most of them have been recovered from sites along the Atlantic and Mediterranean coasts. However, strictly speaking, AOC beakers aren't Bell Beaker artifacts. Rather, their origin is said to be in the Single Grave culture, which is, of course, the northwestern European variant of the Corded Ware culture.

Genotype data for two samples from the Boscombe cemetery were analyzed in and published along with last year's Olalde et al. Beaker paper. In tune with the archeological data, one of these individuals came out very Corded Ware-like, with a lot of steppe ancestry, and the other rather southern, with among the lowest level of steppe ancestry for a Beaker dated to later than ~2500 BCE.

To take a closer look at their genetic affinities, I put together the graph below based on a couple of D-stats of the form D(Mbuti,X)(Yamnaya_Samara)/D(Mbuti,X)(Barcin_N,WHG). The bowmen are labeled I2416 and I2417, and the relevant datasheet is available here.

Considering these results, I2416 and I2417 may have been migrants, or the descendants of migrants, from such relatively far flung places as, say, what are now northern Germany and western France, respectively. [Edit: as per the comments below, these individuals are probably third-degree relatives, which makes it unlikely that they're migrants to the region, although it's still possible that their recent ancestors may have been migrants]

Note also that almost all of the populations are basically sitting between the two bowmen. This indeed suggests to me that the cultural processes and resulting population mixtures that took place at the Boscombe site also played out across the width and breadth of the Beaker realm, giving rise to heterogeneous Beaker groups almost everywhere within it and, eventually, the present-day western European gene pool.

Most of the Scandinavians, as well as the closely related British Anglo-Saxons, are slightly pulled above the red trend line by their excess genetic affinity to Western European Hunter-Gatherers (WHG). This phenomenon appears to date back to at least 2275-2032 BCE, because Nordic_LN:RISE98 is clearly affected by it and dated to this period.

My guess is that Single Grave populations from what is now Denmark and surrounds harbored much higher levels of WHG-related ancestry than the more easterly Corded Ware (aka Battle-Axe) Scandinavian groups, and they passed this onto present-day Scandinavians. Nordic_LN:RISE98, although from a burial site in what is now southern Sweden, might well be of Danish Single Grave origin.

See also...

Single Grave > Bell Beakers

Dutch Beakers: like no other Beakers

Hungarian Yamnaya > Bell Beakers?