Significant research uncovers origins of Indo-European languages spoken by 40% of the global population

A duo of groundbreaking studies, released Wednesday in the scientific journal Nature, has ultimately pinpointed the creators of the Indo-European family comprising over 400 languages, which are now articulated by more than 40 percent of the globe’s populace.

Genetic evidence situates them in contemporary Russia during the Eneolithic era approximately 6,500 years in the past. These linguistic forebears populated areas from the steppe plains adjacent to the lower Volga River to the northern slopes of the Caucasus Mountains, thus researchers have named them the Caucasus Lower Volga group. Genetic analyses indicate they integrated with diverse populations in the locality.

“This signifies an early representation of certain cultural practices that subsequently disseminated throughout the steppe,” remarked lead author David Reich, a genetics professor at Harvard Medical School and in the Department of Human Evolutionary Biology in the Faculty of Arts and Sciences.

This study offers the crucial element to a long-standing linguistic enigma.

Academics first recognized resemblances among the distant languages of Latin, Greek, and Sanskrit in the late 1700s. The so-called steppe hypothesis, developed in the 1800s and solidified in the 1950s, suggested that speakers of the ancestral language of the Indo-European family resided on the Eurasian steppe. Scholars utilized linguistic reconstructions and archaeological findings to place them in regions where modern Russia and Ukraine exist.

The famed Yamnaya people arose as the primary candidates for the origins of this language family. The impactful 2007 publication “The Horse, the Wheel, and Language: How Bronze-Age Riders from the Eurasian Steppes Shaped the Modern World” by anthropologist David Anthony explored the Yamnaya’s influence in propagating a proto-Indo-European language predating written communication.

These nomadic herders were pioneers in “utilizing the bioenergy of the Eurasian grasslands,” clarified Anthony, an emeritus educator at Hartwick College in New York. The Yamnaya were likely the first to manage livestock on horseback and among the early adopters (if not inventors) of oxen-drawn carts.

“I believe it’s impossible to fathom how it would have appeared to others spotting a wagon approaching,” expressed Anthony, a co-lead author of the recent study and a visiting scholar in the Reich laboratory during 2019-2020. “It moved across the terrain, creaking and groaning, towing a ton of equipment. People had never witnessed anything like this before.”

With larger livestock and enhanced mobility, the Yamnaya began exporting their economic system—and their language—approximately 5,000 years ago. “They migrated from the steppes north of the Black and Caspian seas all the way to Mongolia on one side and to Ireland on the other—spanning 6,000 kilometers!” Anthony remarked.

Nick Patterson, deputy director of Reich’s Harvard-based lab and an associate in the Department of Human Evolutionary Biology (HEB), recalls perusing the book and discussing it at a conference a few years post-publication.

Reich’s lab has been investigating proto-Indo-European speakers for over 15 years. In 2014, they presented crucial revelations in a Nature article on what Reich termed “the significant mixing event” that defined modern Europeans, the majority of whom descended from three distinctly separate populations.

The subsequent year, the lab’s researchers delivered a more comprehensive view of the Yamnaya ancestral lineage across the continent. “They revolutionized the population structure of Europe, causing substantial shifts in Germany, Spain, Italy, and Hungary,” explained Reich. “In Britain, over 90 percent of the population was replaced within mere decades.”

The 2015 Nature publication attributed the spread of Indo-European languages across Europe and the Indian subcontinent to the Yamnaya. Subsequent studies from Reich’s lab and others traced their genetic origins to Greece, Armenia, India, and China.

“It resembles a tracer dye,” Reich noted. “You can genuinely observe Yamnaya lineage in all the areas these languages migrated to.”

However, researchers faced a setback within the Yamnaya lineage in the Anatolian peninsula. An extinct group of Indo-European languages was utilized there during the Bronze Age. Linguists have historically assumed they signify an early divergence from proto-Indo-European. In the 21st century, similar conclusions began to surface from ancient DNA studies.

“We know that groups such as the Hittites utilized Anatolian as evidenced by cuneiform tablets,” stated Reich. “However, these individuals did not possess Yamnaya ancestry. We conducted extensive research, analyzing copious amounts of data. We found nothing. Thus, we posited that a deeper population might be the primary source of Indo-European languages.”

The individuals from the Caucasus Lower Volga seem to be that original source, revealing newly identified connections to both the Yamnaya and the ancient Indo-Anatolian speakers who lived in an area that is currently part of Turkey. This discovery represents a collaborative accomplishment that builds on decades of efforts by linguists, archaeologists, and geneticists.

“Currently, it’s quite challenging for Ukrainian researchers to collaborate with Russian scholars,” Reich commented.

The initial paper delineates various lineages stemming from the Caucasus Lower Volga people, including the Yamnaya and the Anatolians, while the samples examined in the second paper offer a wealth of new context regarding the “Yamna” (the Ukrainian term for Yamnaya). Evidence suggests that this culture may have taken root near the small town of Mykhailivka in Southern Ukraine, which has been heavily affected by the ongoing conflict.

“Where the fiercest fighting is occurring right now — that’s the Yamnaya homeland,” Anthony noted.

What has now become evident is that a group from the Caucasus Lower Volga migrated westward and began intermingling with the local populations, thus forming the distinctive Yamnaya genome.

“We can observe that there was a small cluster of villages existing between 5,700 to 5,300 years ago, consisting of only a few thousand breeding individuals,” Reich explained. “Following that, there was a significant population explosion, with these individuals dispersing widely.”

The Yamnaya inherited not only language but also certain traditions from their Caucasus Lower Volga ancestors. Both groups practiced burial in kurgans, or massive earthen tombs. These burial sites, which continue to scatter the region’s flat terrain, have drawn generations of archaeologists and have now facilitated “the genetic reconstruction of their creators’ origins presented here,” as Lazaridis articulated in the initial paper.

“Consider that had the Yamnaya adopted a different cultural practice,” Patterson speculated. “If, for instance, they had opted to cremate their deceased, we might not even possess knowledge of this pivotal culture in human history.”

A portion of the research for these papers received support from the National Institutes of Health and the National Science Foundation.