Some very specific prosodic innovations affected the Balto-Slavic linguistic community, probably at a time when it already showed internal dialectal differences. Whether those innovations were related to archaic remnants stemming from the parent Proto-Indo-European language, and whether that disintegrating community included different dialects, remains an object of active debate.
Experienced researchers, particularly those interested in population structure and historical inference, typically present STRUCTURE results alongside other methods that make different modelling assumptions. These include TreeMix, ADMIXTUREGRAPH, fineSTRUCTURE, GLOBETROTTER, f3 and D statistics, amongst many others. These models can be used both to probe whether assumptions of the model
Some interesting excerpts from the introduction (emphasis mine):
In the 17th century BC the northern reaches of the Únětice culture oecumene experienced a structural crisis and a settlement hiatus; no such interruption in development occurred in the southern or western regions, or further west in the circle
A manuscript co-authored by Angel Carracedo, from the University of Santiago de Compostela, and (always according to him) pre-accepted in Nature, will offer more insight into the population substructure of Spain, based on autosomal DNA.
Carracedo’s lecture about DNA (in Galician), including his summary of the paper (from december 2017):
Some of the points made in the video:
The study shows a situation parallelling – as expected – the expansion of Spanish Medieval kingdoms during the Reconquista (and subsequent repopulation).
In it, the biggest surprise seems to be the greater substructure found in Galicia, the north-western Spanish
Fernando López-Menchero and I have published our first draft on the North-West Indo-European proto-language. Our contribution concerns mainly phonetics, and namely two of its most controversial aspects: a common process of laryngeal loss and two series of velars for PIE.
There is also an updated linguistic model for the Corded Ware substrate hypothesis, which seeks to explain certain similarities between Germanic and Balto-Slavic, and between Balto-Slavic and Indo-Iranian, and potential isoglosses between the three.