Missing link in Indo-European languages' history found

Indo-European languages (IE), which number over 400 and include major groups such as Germanic, Romance, Slavic, Indo-Iranian, and Celtic, are spoken by nearly half the world's population today. Originating from the Proto-Indo-European (PIE) language, historians and linguists since the 19th century have been investigating its origins and spread as there is still a knowledge gap.

The new study published in Nature, also involving Tom Higham and Olivia Cheronet from the University of Vienna, analyzes ancient DNA from 435 individuals from archaeological sites across Eurasia between 6400-2000 BCE. Earlier genetic studies had shown that the Yamnaya culture (3300-2600 BCE) of the Pontic-Caspian steppes north of the Black and Caspian Seas expanded into both Europe and Central Asia beginning about 3100 BCE, accounting for the appearance of "steppe ancestry" in human populations across Eurasia 3100-1500 BCE. These migrations out of the steppes had the largest effect on European human genomes of any demographic event in the last 5000 years and are widely regarded as the probable vector for the spread of Indo-European languages.

The only branch of Indo-European language (IE) that had not exhibited any steppe ancestry previously was Anatolian, including Hittite, probably the oldest branch to split away, uniquely preserving linguistic archaisms that were lost in all other IE branches. Previous studies had not found steppe ancestry among the Hittites because, the new paper argues, the Anatolian languages were descended from a language spoken by a group that had not been adequately described before, an Eneolithic population dated 4500-3500 BCE in the steppes between the North Caucasus Mountains and the lower Volga. When the genetics of this newly recognized Caucasus-Lower Volga (CLV) population are used as a source, at least five individuals in Anatolia dated before or during the Hittite era show CLV ancestry.

Newly recognized population with broad influence

The new study shows the Yamnaya population to have derived about 80% of its ancestry from the CLV group, which also provided at least one-tenth of the ancestry of Bronze Age central Anatolians, speakers of Hittite. "The CLV group therefore can be connected to all IE-speaking populations and is the best candidate for the population that spoke Indo-Anatolian, the ancestor of both Hittite and all later IE languages," explains Ron Pinhasi. The results further suggest that the integration of the proto-Indo-Anatolian language, shared by both Anatolian and Indo-European peoples, reached its zenith among the CLV communities between 4400 BC and 4000 BC.

"The discovery of the CLV population as the missing link in the Indo-European story marks a turning point in the 200-years-old quest to reconstruct the origins of the Indo-Europeans and the routes by which these people spread across Europe and parts of Asia," concludes Ron Pinhasi.