"We find evidence of a previously unknown, large-scale Bronze Age migration within Scandinavia, originating in the east and becoming widespread to the west and south, thus providing a new potential driving factor for the expansion of the Germanic speech community. This East Scandinavian genetic cluster is first seen 800 years after the arrival of the Corded Ware Culture, the first Steppe-related population to emerge in Northern Europe, opening a new scenario implying a Late rather than an Middle Neolithic arrival of the Germanic language group in Scandinavia."
In 2000-1000 BC Scandinavia, they claim to find three populations:
-A Norweigan cluster primarily carrying Y-haplogroup R1a-Z284 (they call it Early Scandinavian)
-A Danish cluster primarily carrying Y-haplogroup R1b-U106 (they call it South Scandinavian)
-A Swedish cluster primarily carrying Y-haplogroup I1 (they call it East Scandinavian)
The paper suggests that Germanic originated in the "East Scandinavian" cluster, also known as the I1 cluster in the Allentoft paper. This is the same population with hunter-gatherer fathers that migrated into Denmark, bringing with them their Neolithic stone cist burial tradition, replacing the aforementioned Early and South Scandinavian populations.
Moreover, the I1 cluster, ancestral to the Germanic people, didn't just carry different Y-DNA haplogroups to the Early Scandinavian and South Scandinavian clusters, they had different ancestry on the whole. This was an entirely different genetic population.
The paper suggests that the East Scandinavian cluster (the I1 cluster) had a cross-Baltic maritime origin due to the samples being modelled as having 7% Latvian Hunter-Gatherer ancestry. However, based on strontium isotope analysis, it is more likely that they came from East Sweden, possibly Mälaren Valley.
I theorised back in December 2023 before the McColl and Allentoft papers were published that the founding population of the Nordic Bronze Age Scandinavians (now confirmed to be the I1 cluster) were not only of a non-WSH origin (carrying I1 Y-haplogroup lineages of hunter-gatherer origin), but even Germanic originated with these people. It is now settled that Germanic comes from the I1 cluster. First the Allentoft paper, now the McColl paper.