The staging point, obviously

The quotes below refer to a couple of individuals buried in the Yampil Barrow Complex, in the forest-steppes of western Ukraine, who were featured recently in the Juras et al. paper on the maternal ancestry of the Corded Ware people (see here). In that paper they were labeled Late Eneolithic poz090 and Yamnaya poz224, respectively. Emphasis is mine:

The central burial of the oldest barrow,