One of the world’s oldest cultivated plants, barley’s history stretches back over 10 millennia. Recent genetic research has unveiled a complex origin story for this vital crop, highlighting the influence of human involvement and environmental factors over millennia. A team of scientists has traced barley’s genome to contributions from five distinct wild populations located in the Fertile Crescent and its neighboring areas. This new discovery upends the conventional wisdom that barley developed from a single cradle. Rather, it proposes that a rich genetic tapestry of contributions shaped its domestication.
They studied 680 IPK genebank barley accessions and 380 wild barley samples from western and central Asia, with DNA sequencing. Her timing, flowering time, growing season. Their study provides new evidence for the timing and geography of barley cultivation. The researchers compared these wild samples with 302 domesticated barley varieties, revealing significant genetic diversity influenced by trade and human migration.
Historical Context and Archaeological Evidence
Barley’s metamorphosis from wild grass to global food staple started well before our ancestors lived in any type of agricultural civilization. Barley was among the earliest of crops domesticated, more than 27,000 years ago. This important step began with the report of the appearance of an important haplotype that is vital to its cultivation. This non-brittle ear haplotype promoted retention of barley grains on the plant – a helpful adaptation to make harvesting easier.
Located on the shores of the Sea of Galilee, the Ohalo site provides remarkable archaeological evidence. This body of evidence speaks to the extraordinarily early cultivation of barley. Excavations at this riverine site have revealed domesticated barley between 21,000 and 26,000 years ago. This glowing discovery agrees with the findings of genetic studies. That’s an amazing testament to the role of this region in the cradle of early agriculture.
“These discoveries strengthen and add a genomic dimension to our findings of the 23,000-year-old cereal agriculture at the Ohalo site,” – Prof. Ehud Weiss
A Mosaic Genome and Its Implications
The recent study reveals that barley’s genome is not derived from a single source but rather is a mosaic formed through contributions from five wild populations. This genetic diversity is a product of multiple domestications occurring in separate places. This upends the long-held assumption of a single point of origin.
Dr. Martin Mascher emphasized the importance of understanding this complexity. “Our study shows how closely human history is linked with the history of cultivated plants.” As he explained it, riding barley’s DNA is like reading millennia of human civilization. Our research indicates that gene flow from local wild populations and domesticated varieties was integral. This critical process has historically played a major role in increasing today’s genetic diversity in barley.
“Barley does not come from a single origin, as long assumed,” – Yu Guo
The Evolution of Barley Cultivation
The growing of barley had begun with the first Neolithic Revolution, long before our ancestors built permanent cities. Technical evidence almost conclusively puts the spread of the crop outside the Fertile Crescent through a more active process of trade and human migration. This expansion was by no means simple. It was influenced by continuous contact between wild ancestral populations and selectively bred domesticated strains.
In examining ancient barley grains from sites like Yoram Cave, Abi’or Cave, and a copper mine near Timna, researchers noted an increase in genetic diversity over time. These grains, which date from 2,000 to 6,000 years ago, provide additional evidence for how human actions shaped the development of barley.
“This expansion was shaped by repeated gene flow between local wild populations and already domesticated barley varieties—as well as by human migration and trade,” – Dr. Martin Mascher