Population Replacement in Neolithic Britain

In listening to podcasts about disease affecting history, and writing that up a bit myself, I wondered about the rapid turnover of population in the British Isles near the beginning of the 3rdMillennium BC. 90% genetic turnover in a few centuries is a lot.  To get the time frame into your imagination, the peoples that started building Stonehenge in 3000 BC were not closely related to those who put the final touches on it in 2000 BC. It is the crossover from Neolithic to Bronze Age.

Anthropological debates can get oversimplified into Pots, not People – or its reverse. Sometimes the same studies will be used to back up either point of view.  Did the ideas and techniques spread from one tribe to another, or did tribes move into new areas, taking over land once held by others? As we can extract DNA from more and more remains, we are now awash in new information.  Most anthropologists lean toward one interpretation or the other, but few to exclusivity.  There are instances where clear imitations, but inferior ones, of one type of pottery shows up at the other end of an empire suddenly, which is excellent evidence that it was the idea that moved, not the people.  At other sites we can find mass graves of people with evidence of damage from weapons, with DNA quite distinct from those who we know came after, clearly suggesting one population group flat-out replaced another.  But other evidence can be ambiguous.  If the y-chromosome lines largely changed but the mtDNA remains the same we suspect the men were killed and the women taken as mates, with unknown level of cooperation about that.  Yet without a timeline it may at least partly be that the men were outcompeted for mates in a few generations because the new arrivals had horses, or cattle, or other wealth.  Whether a percentage was sold into slavery, or whether a conquering people were only an elite group that ruled and extracted resources without leaving much genetic mark is difficult to discern.

I’m looking around for any discussion of the possibility that the new population entering the British Isles were invaders bearing diseases as much as swords.  (Those work hand in hand, though.  A population cut in half is ripe for conquest, with perhaps even more diseases coming in tow, as happened to the native populations of the Americas. The Four Horsemen of the Apocalypse often ride together.) I can’t find any mention of it.  I will likely go looking for a place to throw that into a comment section of someone smarter than me. 90% turnover in a few centuries seems to me an at least plausible result of diseases coming in, followed by conquest.  As armies on the move scoop up the food and other resources from the countryside, this could also bring in famine, further weakening defenses against disease.  If you know anything, fill me in.