Germanic lineage arrived from the east?

[Jaska]

McColl et al. 2024: "Steppe Ancestry in western Eurasia and the spread of the Germanic Languages"
https://www.biorxiv.org/content/10.1101/...3.584607v1

The genetic part is discussed over here:
https://genarchivist.com/showthread.php?tid=639

...but I think it is clearest to discuss the linguistic part on this linguistic subforum. Here are some interesting quotes from the study:

“Linguistically, the Late Bronze Age is the period during which Palaeo-Germanic donated vocabulary to Finno-Saamic in the east and adopted vocabulary from Celtic in the south, suggesting that it was spoken widely among East Scandinavians distributed between Sweden and Denmark, and possibly also in the Nordic Bronze Age communities in Finland and Estonia.” (Page 34)

“At any rate, the persistent genetic border between Southern and Eastern Scandinavians throughout the Iron Age suggested that the Proto-Germanic speech community united these different populations until its dissolution around 2000 BP.” (Page 35)

“Our results demonstrate the arrival of a strong component of North German IA ancestry, in combination with a series of ancestries previously associated with Celtic-speaking groups and populations carrying European Farmer (in addition to GAC) ancestry from north-western Europe. In the Danish islands, the shift amounts to a virtually complete population replacement.” (Page 36)

“In Denmark and Sweden we show strong genetic evidence suggesting that observed archaeological and linguistic changes are linked to the migration of Iron Age Danes. Based on the genetic heterogeneity of the migrating population and the inability to identify a suitable source population, it appears that between 1500 and 1200 BP was likely the outcome of an amalgamation among several migrating and local groups, comparable to the formation processes among Germanic groups on the continent. In contrast, in Norway, the adoption of Old Norse and similar social changes as seen in South Scandinavia occurred with limited genetic impact from Southern Scandinavian and must have been more cultural in nature. With the exception of a single early Viking sample, the majority of Viking Age Norwegians appear either to carry local ancestry, or to reflect back migrations from Celtic regions of Britain and Ireland. Of note, the border between the East and West Norse languages closely corresponds closely to that of the Southern Scandinavians and Western Scandinavians clusters during the Viking Period (Figure 6).” (Page 37)

“Our results additionally call for a reappraisal of the linguistic evidence concerning the hypothetical migration of Germanic from the Baltic into Scandinavia and its trajectory of this linguistic subgroup from the Indo-European steppe. The formation of East Scandinavians out of Baltic populations finds an evident linguistic analogue in the isoglosses shared between the Germanic and Balto-Slavic branches of the Indo-European language family, which point to prehistoric borrowing, a linguistic subclade, or both. On the other hand, the relatively late, Bronze Age arrival of agriculture in the Baltic vs the presence in Proto-Germanic of agricultural terms inherited from Indo-European raises a question on the suitability of the archaeological context of this area as a linguistic stepping stone during the Late Neolithic.” (Page 39)

“S6.4.2. Y-chromosome analysis
Haplogroup I1a-DF29 first appears in Scandinavia in the Bronze Age, and its vast number of local descendant lineages seem to indicate an in situ diversification and point of origin (Figure S3). Haplogroup I1a2a (I1a-Z59) is most the common variant of I1a-DF29 among both 0_1_2 SouthScan and 0_1_3 EastScan clusters, but when restricting to individuals older to 2,800 BP, all four are in the Eastern Scandinavian cluster (Figure S4). This likely indicates that its presence in the South Scandinavian cluster to be associated with the later mixture from an Eastern Scandinavian source.”