A handful of unremarkable bone fragments from caves in southern Siberia have turned out to hold an extraordinary evolutionary story. According to an online report by Phys Org, ancient DNA recovered from the remains has revealed a previously unknown bovine species that lived across the region for hundreds of thousands of years and shared a distant ancestry with modern yaks. The discovery, published in Current Biology, adds another chapter to the complex history of Ice Age biodiversity in the Altai region.
A species hidden in small bones
The discovery emerged from fragments recovered from Denisova Cave and other archaeological sites across southern Siberia. Many of the bones were too incomplete or poorly preserved to identify by appearance alone. Genetic analysis, however, offered a much clearer picture, claims the online report.Researchers from the Center for Paleogenetics in Stockholm, the University of California, Santa Cruz, and the University of Vienna analyzed 20 ancient genomes spanning roughly 200,000 years. Comparison of these genomes with those of modern and extinct bovines revealed that the remains represented a previously unrecognized lineage. The animal was related to modern yaks but had followed an independent evolutionary trajectory for a remarkably long period. Genetic evidence suggests that its lineage began separating from that of modern yaks around 400,000 years ago and became fully distinct roughly 250,000 years ago, the Phys Org report adds.
Climate may have influenced its evolution
The timing of the split provides clues about how climate affected the evolution of the species. Around 400,000 years ago, the region experienced a particularly strong warm climatic period. Changes in temperature and habitat may have separated populations, eventually allowing them to evolve independently.The comparison is striking because the estimated age of this divergence is similar to the period when brown bears and polar bears are thought to have begun following separate evolutionary paths, the report adds.The genetic record also points to another major environmental shift. During the last interglacial warm period, around 120,000 years ago, the newly identified bovine appears to have undergone a population replacement accompanied by declining genetic diversity. For an animal adapted to cold conditions, prolonged warming may have created significant ecological pressure.
Another mystery from the Altai
The discovery adds to the growing reputation of the Altai region as an important refuge for biodiversity during repeated Ice Age cycles. Denisova Cave has already produced evidence of Denisovans, an archaic human population identified through genetic analysis of fossil remains.The new bovine discovery reveals the region’s significance extended way beyond human evolution. It may have served as a long-term refuge where animal populations survived dramatic climatic fluctuations and developed into distinct lineages.Interestingly, researchers found little evidence that the newly identified bovine interbred with other large bovines living in the region, including steppe bison and aurochs, the wild ancestors of modern cattle.
An extinction still shrouded in mystery
The youngest specimen examined in the study dates to around 27,000 years ago. The species disappeared sometime after that, but researchers cannot yet determine exactly when or why it became extinct. Modern wild yaks are now restricted largely to high-elevation areas of the Tibetan Plateau, making the Siberian lineage a fascinating reminder of how much broader the historical range of yak-like animals once was.For now, the species remains without a formal scientific name. DNA evidence can reveal its evolutionary identity, but researchers need to compare the genetic findings with previously described yak-like fossils from the region before determining whether those remains belong to the same animal. Further work could eventually put a name, appearance and clearer ecological history to this long-lost Siberian bovine.Images Courtesy: Phys Org
