The succeeding culture, named after its own distinctive pottery style, the Bell Beaker, has been discovered to be about 70% Yamnaya in its ancestry. Percentages of ancestry vary quite a bit, by region; showing that there was quite a bit of chance involved in these meetings of natives and immigrants.
This passage shows that the Bell Beaker culture was largely descended from the Yamnaya people, with about 70% of their ancestry coming from them. It also notes that ancestry percentages differed by region, suggesting random variation in how native and immigrant groups mixed.