This parallels the practice of the Cucuteni-Trypillia culture, and is in contrast with the later Yamnaya culture, which practiced tumuli burials. In Serednii Stih culture, the deceased were laid to rest on their backs with the legs flexed. The use of ochre in the burial was practiced, as with the kurgan cultures. For this and other reasons, Yuri Rassamakin suggests that the Serednii Stih culture should be considered as an areal term, with at least four distinct cultural elements co-existing inside the same geographical area. Language In the context of the modified Kurgan hypothesis of Marija Gimbutas, this pre-kurgan archaeological culture could represent the Urheimat (homeland) of the Proto-Indo-European language. Others associate this with the later Yamnaya culture. Physical type Examination of physical remains of the Serednii Stih people has determined that they were Europoid. A similar physical type prevails among the Yamnaya, who were tall and powerfully built. People of the neighboring Khvalynsk culture were less powerfully built. People of the preceding Dnipro–Donets culture were even more powerfully built than the Serednii Stih and Yamnaya. Genetics Mathieson et al. (2018) included a genetic analysis of a male buried at Olexandria (Ukraine) and dated to 4153-3970 calBC, ascribed to the Serednii Stih culture. He was found to be carrying the paternal haplogroup R1a1a1, and the maternal haplogroup H2a1a. He carried about 80% Western Steppe Herder (WSH) ancestry and about 20% Early European Farmer (EEF) ancestry. This Seredny Stig male was thought to be the first steppe individual found to have been carrying EEF ancestry. As a carrier of the 13910 allele, he was supposed to be the earliest individual ever examined who has had a genetic adaptation to lactase persistence. However, the recent publication by David Reich Lab, October 2021, presented another date from a different sample of the same individual, 2134–1950 cal BC, which could actually belong to Srubnaya culture period, as Haplotree Information Project considers this sample I6561 is from around 3650 ybp (c. 1700 BC), and belongs to Y-DNA R1a-F2597*, corresponding to R1a-Y3. The WSH genetic cluster was a result of mixing between Eastern Hunter-Gatherers (EHGs) from Eastern Europe and Caucasus hunter-gatherers (CHGs). This mixing appears to have happened on the eastern Pontic–Caspian steppe starting around 5,000 BC. A preprint by Matilla et al. (2022) presented whole-genome analysis of a Serednii Stih individual, dated to 4320-4052 calBC, from the Deriivka II archaeological site in the Middle Dnipro