Study reveals genetic signatures of chickpea cultural crossroads

With its nutty flavor and dense nutrient profile, the humble chickpea has captivated palates and fueled civilizations for millennia. From its ancient origins to its widespread use in modern kitchens and restaurants around the world, this legume demonstrates both culinary versatility and cultural significance. Despite the importance of traditional cuisines on several continents, the origin, diversification and spread of chickpeas in the Middle East, South Asia, Ethiopia and the Western Mediterranean have remained a mystery.

A new study in Molecular biology and evolution titled “Historical routes for domesticated chickpea diversification inferred from landrace genomics” highlights the profound effects of human migration and trade on chickpea gene pool.

The study – led by Anna Igolkina of Peter the Great Polytechnic University in St. Petersburg, Eric von Wettberg of the University of Vermont and Sergey Nuzhdin of the University of Southern California – used genetic data from more than 400 chickpea specimens collected in the 1920s and 1930s. The collection included both desi and kabuli subtypes, which differ in color and size, despite having no clear geographic or genetic boundary between the two.

The chickpea samples came from nine different geographical regions: Northern Mediterranean, Southern Mediterranean, Turkey, Lebanon, Ethiopia, Black Sea, Western Uzbekistan, Eastern Uzbekistan and India. To analyze the data, the researchers developed two new models, which they named popdisp (popularregulation displayersals) and migadmi (Merations and admittedlight fixtures).

The authors used the popdisp model to understand how chickpeas dispersed in each of the geographic regions. They compared two scenarios, one in which chickpeas spread along routes easier for humans to cross (i.e. possible historic trade routes), and the other in which Chickpeas disperse over distances in a simple linear fashion, regardless of geographical barriers in between.

According to Igolkina, “Our study reveals an intriguing finding regarding genetic relatedness between local chickpea races in different geographic regions. Contrary to the hypothesis that genetic similarity is determined by linear distance, our results suggest that it is influenced more by human travel costs. This implies that the spread of chickpea in each region occurred primarily along trade routes, rather than by simple diffusion.”

Using the migadmi model, scientists sought to uncover the origin of the Ethiopian desi population. “Ethiopian chickpeas have a unique flavor,” says von Wettberg, “with the tartness of the desi black chickpeas found in the Indian varieties, but also a hint of sweetness.”

Previous studies have suggested two possible origins for Ethiopian chickpeas – either an Indian origin supported by morphological similarities, or a Middle Eastern origin given evidence of human migration from western Eurasia to Africa. from the east about 4,500 years ago. Interestingly, the results revealed that both scenarios may be true, finding that Ethiopian chickpeas share ancestry with Indian, Lebanese, and Black Sea source populations.

von Wettberg notes “For me, the most exciting discovery is that Ethiopian chickpeas are a mixture of Middle Eastern and South Asian ancestry. The cultural connection of Ethiopians to the Middle East is widely known, exemplified by their heritage Less well known is the extent and importance of the Indian Ocean trade routes, which were both an important Silk Road sea route and a means by which agricultural and cultural exchange occurred between South Asia and East Africa.

The migadmi model also revealed the possible origin of the kabuli type from a local population of desi chickpeas in Turkey. This disputes the linguistic suggestion that the Kabuli type arose in Central Asia and is named after the city of Kabul (in modern Afghanistan).

While these findings offer fascinating insight into the natural history of chickpea and its interconnection with trade routes and human migrations, the implications of this study extend far beyond chickpeas alone.

“The importance of this work lies not only in expanding our knowledge of the history of chickpea, but also in developing the two new models, popdisp and migadmi,” notes Igolkina. “These models can be applied together or separately to analyze migrations and admixtures in other species. The basic modeling technique used in these models, analysis of compositional data, allows their extension to model multiallelic genetic markers This is of particular interest when analyzing structural variants, the analyzes of which are becoming increasingly common.”

von Wettberg agrees: “A central part of our work is to develop new tools to examine complex migration patterns. natural species. »

Provided by SMBE Journals (Molecular Biology and Evolution and Genome Biology and Evolution)