Interesting little article in the Independent. Apparently our Neolithic forbears were of Mediterranean/Middle Eastern origin and were 90% were wiped out by plague carried by 'Beaker' incomers. Now that's something that I hadn't considered for the large cultural shift during the Bronze Age. The article states that that only Sardinia has remnants of it's original Neolithic population.
Also in the Daily Tory
http://www.dailymail.co.uk/sciencetech/article-5413607/Neolithic-farmers-wiped-Beaker-people.html
Different mag suggests that Bronze Age plague not spread by fleas.
http://www.sciencemag.org/news/2015/10/bronze-age-plague-wasnt-spread-fleas
Cambridge Archaeology
http://www.cam.ac.uk/research/news/plague-in-humans-twice-as-old-but-didnt-begin-as-flea-borne-ancient-dna-reveals
A couple of other articles worth a butchers too...