It is widely acknowledged that the ancestors of all the non-African (Eurasian) populations migrated out of the African continent approximately 70-60 kya (Vallini et al. 2022). During their initial expansion into Eurasia, possibly somewhere in the Near East, they interbred with the Neanderthals, resulting in an estimated 2-3% Neanderthal admixture in the majority of the later populations (Posth et al. 2023). This initial group of Eurasian population further split into West and East Eurasian groups, believed to have occurred between 45 to 38 thousand years ago.

The oldest Homo Sapiens specimen sequenced to date is a female individual from Zlaty Kun (Czech Republic) is radiocarbon dated to over 45 ka. The Zlaty Kun individual represents an ancestral lineage that is basal to both West and East Eurasians (Vallini et al. 2022). In contrast, the second oldest human samples from the Bacho Kiro cave in Bulgaria, dated around 45 thousand years ago, exhibit a closer genetic affinity with ancient and contemporary East Asians than with Europeans. Moreover, individuals from Bacho Kiro display a notably higher proportion of Neanderthal admixture, suggesting recent interbreeding with Neanderthals within the last few generations (Vallini et al. 2022). On the other hand, the genetic positioning of the Ust’Ishim individual (45 ka) from Omsk Oblast, Russia, contemporaneous with Bacho Kiro, remains ambiguous. Nevertheless, statistical support leans towards the East Eurasian lineage for Ust’Ishim (Vallini et al. 2022, supplementary information).

So, to summarise, the latest findings on the oldest human samples indicate that the initial migration wave out of Africa, as represented by Zlaty Kun, had already populated Europe prior to 45 ka. Around 45 ka, individuals with a genetic affinity to East Eurasians emerged in locations such as Bacho Kiro cave in Bulgaria and Ust’Ishim in Russia. Subsequently, Oase1 in Romania (40 ka, likely descended from Bacho Kiro) and the Tianyuan individual in China (40 ka) also displayed similar genetic profiles. 

It is also noteworthy that the ancestral lineage represented by individuals predating 40 ka (with the exception of Tianyuan) appears to have either become extinct or assimilated into later migrating populations (Posth et al. 2023). 

Some time after the appearance of the East Eurasian related samples, we see the occurrence of the samples carrying ancestries that derive primarily from the lineage leading to present-day Europeans (West Eurasian). The oldest human genomes reflecting this lineage include Kostenki 14 (38 ka) from western Russia and GoyetQ-116-1 (35 ka) from Goyet cave in Belgium. The ancestral signature found in Kostenki 14 later contributed to the Vestonice cluster (named after the Dolní Věstonice site in Czechia), associated with the archaeologically defined Gravettian Culture (33-36 ka). This ancestral lineage was shared among individuals from the Gravettian Culture in Central and Southern Europe but disappeared after the Last Glacial Maximum (LGM). 

Conversely, the ancestry related to GoyetQ-116-1 reappeared after the LGM in individuals associated with the archaeological Magdalenian Culture (19-14 ka) from Iberia across Central Europe to Eastern Europe. This lineage was later largely replaced by the Epigravettian-associated (24-12 ka) Villabruna (WHG) cluster (Posth et al. 2023).