The first European farmers were pretty restricted in their environmental range. Earlier in the chapter, it explains this is the cause of WHG survival in the other areas, and why EEF and WHG intermarried so little.
In this thread, EEF is Early European Farmer, WHG is Western Hunter Gather, and IE is Indo-European. They are three ancient races that played a large role in European prehistory.
WHG+EHG=SHG. A paper last year found the hunter gatherers from Western Europe to Eastern Siberia were part of the same cline
EEF (with some WHG admixture) replaced the SHG in Sweden. The more effective fishing based economy of the WHG in the Baltic led them to hold out against the EEF.
SHG by this time had an advanced naval tradition - perhaps their language survives in the non-Indo-European vocabulary relating to seafaring in the Germanic languages
Small WHG population isn’t surprising, but large EEF in Britain population settling in Britain is. Seems like a state organized large scale settlement, otherwise they’d have had high ROH from bottleneck
Shift towards pastoralism a few hundred years before IE showed up is an important insight from the book. Cattle ranching is a more mobile way to transport food and wealth than agriculture
Book doesn’t have much new for those that have followed ancient DNA scene for the last few years, but it is a nice compilation with everything in one well organized and presented book.