Proto-Georgians (Proto-Kartvelians) settled in Caucasus 50,000 years ago and provided half of the necessary DNA for the Yamnaya people in 3300-2600 BC. For many years, there has been a common belief among scientists that there were three different groups that made up modern-day Europeans – Middle Eastern agriculturalists, indigenous hunter-gatherers, and the Yamnaya tribes from the Pontic-Caspian steppes. Generally, the belief has been that they arrived in Europe around 5,000 years ago during the Bronze age. However, this is now set to change thanks to new reports. In Western Georgia, two separate burials were found both with a minimum age of 10,000 years. By assessing the DNA within, we can now suggest that there was a fourth group in Georgia who lived in the Caucasus Mountains and they provided half of the necessary DNA for the Yamnaya people.

According to Jones et al. (2015) and Haak et al. (2015), autosomic tests indicate that the Yamnaya people were the result of a genetic admixture between two different hunter-gatherer populations: distinctive "Eastern European hunter-gatherers" (also known as "Eastern Hunter-Gatherers" or "EHG") with high affinity to the Mal'ta–Buret' culture or other, closely related people from Siberia and a population of "Caucasus hunter-gatherers" (CHG) who probably arrived from the Caucasus. Each of those two populations contributed about half the Yamnaya DNA. According to co-author Andrea Manica of the University of Cambridge:

The question of where the Yamnaya come from has been something of a mystery up to now ... we can now answer that, as we've found that their genetic make-up is a mix of Eastern European hunter-gatherers and a population from this pocket of Caucasus hunter-gatherers who weathered much of the last Ice Age in apparent isolation.

Several genetic studies performed since 2015 have given support to the Kurgan theory of Marija Gimbutas regarding the Indo-European Urheimat – that Indo-European languages spread throughout Europe from the Eurasian steppes and that the Yamnaya culture were Proto-Indo-Europeans. According to those studies, haplogroups R1b and R1a, now the most common in Europe (R1a is also common in South Asia), would have expanded from the Pontic–Caspian steppes, along with the Indo-European languages. They also detected an autosomal component present in modern Europeans which was not present in Neolithic Europeans, which would have been introduced with paternal lineages R1b and R1a, as well as Indo-European languages in the Bronze Age.

Recent studies display genetic continuity between the paternal lineages of the Dnieper-Donets culture and the Yamnaya culture, as the males of both cultures have been found to have been mostly carriers of R1b, and to a lesser extent I2. While the mtDNA of the Dnieper-Donets people is exclusively types of U, which is associated with the Eastern Hunter-Gatherers (EHGs) of Eastern Europe and the Western Hunter Gatherers (WHGs) of Western Europe, the mtDNA of the Yamnaya also includes types frequent among Caucasian Hunter-Gatherers (CHGs) and Early European Farmers (EEFs). This admixture is referred to as Western Steppe Herder (WSH), and has earlier been found among the Sredny Stog culture and the Khvalynsk culture, who preceded the Yamnaya culture on the Pontic–Caspian steppe. Unlike their Khvalynsk predecessors however, the Y-DNA of the Yamnaya is exclusively of EHG and WHG origin. This suggests that the leading clans of the Yamnaya were of EHG and WHG paternal origin. Admixture between EHGs and CHGs is believed to have occurred on the eastern Pontic-Caspian steppe starting around 5,000 BC, while admixture with EEFs happened in the southern parts of the Pontic-Caspian steppe sometime later. As Yamnaya Y-DNA is exclusively of the EHG and WHG type, the admixture appears to have occurred predominately between EHG males, and CHG and EEF females. According to David W. Anthony, this implies that the Indo-European languages were the result of "a dominant language spoken by EHGs that absorbed Caucasus-like elements in phonology, morphology, and lexicon."(spoken by CHGs)