At https://www.dnaweekly.com/blog/a-map-of-europe-based-on-haplogroups/ … the map at the link shows the genetic composition of the countries of Europe – and how migration into the continent has created different haplogroup clusters in different countries and regions. Haplogroups occur on the female, mt DNA side, and the male, Y-DNA side. The former seems to have a greater role for older European ancestry – even back into the Mesolithic. The Y-DNA, on which this map is based, highlights influxes and invasions that have occurred, usually in the period from the Neolithic to the Iron Age.
At https://phys.org/news/2023-05-dna-year-old-plague-discoveredthe-oldest.html … researchers at the Francis Crick Institute have identified three cases of plague going back around 4000 years ago – the oldest evidence, so far, of plague in Britain. Two were found in a mass burial site in Somerset and another one in a ring cairn in Cumbria. Plague has previously been identified at various sites across Europe and the steppe zone and is dated variously between 5000 and 2500 years ago [3000 to 500BC]. The new victims fit into that general pattern – and more especially, into known migration movements out of the steppe zone. Plague is first recorded around 3000BC, coinciding with movement out of the steppe towards eastern and central Europe. The find around 4000 years ago may indicate the Beaker Folk, with ultimate steppe descent, brought it across to Britain. On the other hand, scientists may yet find evidence of plague in Britain around 3000BC, and another source of the plague would be required.