Europe's two inland seas, the Black Sea and the Caspian Sea, are separated by a strip of land, consisting of the Caucasus Mountains and adjacent steppe lowlands,  that connected the people that lived on their shores for millennia. Archaeologists have been aware that the inhabitants of the land between the two seas travelled far and wide  during the Stone Age and the Early Metal Ages (Eneolithic/Copper Age and Early Bronze Age), but the full extent of their travels only became apparent with the latest analysis of the area's ancient genomes. The presence of carriers of the North Caucasus-Lower Volga (CLV) genetic ancestry¹ was revealed  in individuals as far as the Hungarian Valley and was detected in all inhabitants of the North Pontic, from the Neolithic fisher-hunter-gatherers of the Dnipro Valley to the Ukraine's Eneolithic farmers of Trypillia. Many of these populations also harbored genetic ancestry of Early European farmers, which was known and expected to be found in Trypillians, but came as a surprise having been discovered in  the Neolithic Black Sea (Pontic) foragers. 

Through this study, it became apparent that in traversing the Carpathian Mountains early Trypillians came into contact with the CLV travelers in the Danube-Dniester delta interfluve, and a new archaeological culture, known as Usatove, had emerged from these interactions. The Usatovans, being genetically half Trypillians and half CLV, buried their dead at elaborate ritual centers, as well as at sanctuaries constructed in the North Pontic steppe before Usatove came into existence. One such sanctuary lies beneath the Revova Kurgan 3 in the Odesa region of Ukraine, built at a strategic point on a river valley to be seen for many kilometers around². The Revova sanctuary combined architectural elements from the Balkans and the Caucasus, reflecting the integrated nature of the communities in the area where it was constructed. The partition of the ritual space at Revova suggests the sanctuary had an astronomical function.

The Revova kurgan is part of a kurgan chain extending from one of the Usatove's ritual sites due north, to a concentration of Trypillian mega settlements at the steppe-forest steppe boundary in south-central Ukraine. Trypillian mega settlements are a still not well-understood Eneolithic phenomenon where thousands of ancient farmers congregated at sites displaying evidence of an almost modern city-type neighborhood planning, with a circular arrangement of individual households and a communal center with a large communal building and a probable common area in the middle. The main burial of the southernmost kurgan in the chain (Katarzhyno Kurgan 1) belongs to an Eneolithic female possibly of  Caucasus  genetic ancestry who stood about 185 cm tall³, nearly 20 cm taller than her European male contemporaries⁴, and the burial position of the main burial at the northernmost kurgan of this kurgan chain nearest to the mega settlements is shared with a Yamna culture burial in eastern Ukraine displaying an Usatove-like genetic ancestry. 

The Yamna succeeded the rich tapestry of Eneolithic archaeological cultures of the North Pontic by the end of the Eneolithic. The Yamna is known for its incredible speed of advance, bringing along new genes and new cultural elements such as the Indo-European languages and associated religious system to all corners of Europe and substantial parts of Asia approximately  five thousand years ago. It has been estimated that 80% of the Yamna's ancestry comes from CLV populations and 20% is from the Neolithic inhabitants of the Lower Dnipro and Middle Don valleys¹. The present paper suggests that a long-sought birthplace of the Yamna people may be in the Lower Dnipro Valley, around a famous Mykhailivka archaeological site.

The Yamna buried their dead under earth mounds (kurgans) and covered the interred with ample amounts of ochre, like their predecessors from the Caucasus Piedmont, to a point where  ochre saturated the ground around the buried. The use of ochre in burial rites is a millennia-old tradition in the Ponto-Caspian region. The Neolithic ancestors of the Yamna from the Dnipro Valley  used ochre to a similar extent. Graves of the Eneolithic CLV people in the North Caucasus and the North Pontic are even referred to as Ochre Graves by some scholars⁵ because of the overabundance of ochre in the burials.

The origin of the kurgan burial tradition in the Pontic steppe is not a well understood subject. Katarzhyno Kurgan 1 is among the oldest kurgans in the region. There is a more than 700-year gap between the main burial (#10) at Katarzhyno and the next burial (#13) in the kurgan, the latter being one of  the earliest Yamna burials in the North Pontic. It is not possible to determine if individuals in the two burials are related. All that can be gathered is that their mitochondrial DNA (mtDNA) lineages belong to subdivisions of macrohaplogroup U. Yamna individuals in the Katarzhyno Kurgan 1 did share genetic ancestry at the whole genome (being part of the Core Yamna genetic group) and uniparental lineage levels. Such as, individuals in burials 13 and 1, buried 400 years apart, shared both mtDNA (haplogroup U4a) and Y chromosomal (haplogroup R-Z2108) lineages. 

Many of the North Pontic kurgans served as burial sites for hundreds, sometimes thousands, of years. The last burial in the Katarzhyno 1 Kurgan was made at around the 22^nd century BCE, while the most recent burial in the Revova 3 kurgan dates to the 19^th century CE. Such ritual continuity is not unique in the North Pontic region. Vertebra Cave, a ritual site of the Trypillia culture containing some of the very few human remains of Trypillians ever found, was likely in a near continuous use by Trypillians for almost 1000 years⁶, continuing to be utilized in the Late Bronze Age, the Iron Age, and the Roman period. The so-called Mariupol-type cemeteries of extended burials left by the Neolithic fisher-hunter-foragers of the Dnipro Valley were continuously used from the end of the Last Ice Age till the Early Bronze Age, six thousand years in total. Some scholars refer to this remarkable ritual continuum as the "continuity of sacred spaces."²

The study of these unique monuments of human heritage was interrupted by the Russian invasion of Ukraine. In the course of the invasion many monuments and museums housing precious archaeological artifacts were damaged or destroyed. The fate of Ukrainian heritage collections in the territories occupied by Russia remains uncertain. As the war rages on, the entire cultural history of the North Pontic region stands at risk. The human tragedy that resulted from this aggression is reasonably front and center and must end. As the people of Ukraine will begin the process of rebuilding their lives, they will undoubtedly resume a vigorous and secure examination of their ancient history, and new exiting discoveries will be sure to follow. Until then, the Genomic History of the North Pontic Region paper offers a captivating glimpse into a remarkable journey of the people who inhabited Europe's crossroads during a turning point in its history, which was discovered during a critical juncture in its present. 

References

1. Lazaridis, I. et al. The genetic origin of the Indo-Europeans. Nature https://doi.org/10.1038/s41586-024-08531-5 (2025).
2. Ivanova, S. et al. The continuity of sacred spaces in the North Pontic steppe: A case study of the Revova Kurgan 3 (Odesa Region, Ukraine). Manuscript under review.
3. Nikitin, A. G., et al. Subdivisions of haplogroups U and C encompass mitochondrial DNA lineages of Eneolithic–Early Bronze Age Kurgan populations of western North Pontic steppe. J Hum Genet https://doi.org/10.1038/jhg.2017.12 (2017) .
4. Marciniak, S. et al. An integrative skeletal and paleogenomic analysis of stature variation suggests relatively reduced health for early European farmers. PNAS 
   https://doi.org/10.1073/pnas.2106743119 (2022).
5. Govedarica, B. Zepterträger, Herrscher Der Steppen: Die Frühen Ockergräber Des Älteren Äneolithikums Im Karpatenbalkanischen Gebiet Und Im Steppenraum Südost-Und Osteuropas. (Verlag Philipp von Zabern, Mainz am Rhein, 2004).
6. Nikitin, A. G., Sokhatsky, M. P., Kovaliukh, M. M. & Videiko, M. Y. Comprehensive Site Chronology and Ancient Mitochondrial DNA Analysis from Verteba Cave – a Trypillian Culture Site of Eneolithic Ukraine. Interdisciplinaria Archaeologica. Natural Sciences in Archaeology. 1, 9–18 (2010).