Archaeologists digging at an ancient, abandoned settlement at Gurga Chiya in Iraqi Kurdistan had a simple way to tell what was mud wall and what was the interior of a room. The dirt that had filled the settlement’s chambers in the thousands of years since its abandonment was packed – simply packed – with lentils.
"The lower 30cm (12in) of the room fill is black with lentils; large parts are pretty much 100% lentil," wrote archaeologist Mary Shepperson in a 2017 piece for The Guardian about the excavation in Iraqi Kurdistan. And this is far from the only lentil cache to be found by archaeologists in the Middle East. In 1983, at a site in Israel dated to around 10,000 years ago, more than a million lentils were uncovered.
Wheat and barley get a lot of play as some of the first plants domesticated at the beginning of agriculture in the Fertile Crescent region. But the lentil was there, too. How long has this humble legume been with us, and when and why was it tamed?
Civilisations began to farm lentils at about the same time as wheat and barley, says Hugo R Oliveira, a geneticist who studies the diminutive pulse at the Universidade do Algarve in Portugal. They are part of a pattern around the world where people first turned to agriculture, rather than hunting and gathering. "In all of them, there's always a cereal and there's always a legume," Oliveira says. He numbers them off: In Mesoamerica, maize and beans; in West Africa, sorghum and cowpeas; in East Asia, rice and soybeans. And in the Middle East? Wheat, barley and lentils.
That's likely because the cereals and grains pack a carb-heavy punch for quick energy, Oliveira says, while the legumes give protein – protein is behind around 25% of lentils' calories. You can build a complex society on that pairing, and many times over the course of human history, people have. In the ancient Middle East, lentils were one of the main sources of protein, far more important in most people's diets than meat or animal products.
"That is still relevant for today's world," said Oliveira. "In the developed world, we tend to think the main source of protein is meat. But in low and middle-income countries, the main source of protein is still plant-based." The Ancient Egyptians were likely the same; the pyramids were built by people who were fuelled by lentils, peas and chickpeas.
The DNA information they've generated may help researchers identify the genetic underpinnings of traits like resistance to extreme heat and diseases
Curious about the process that took the lentil from wild plant to the foundation stone of civilisation, Oliveira and his colleagues sequenced the DNA of domesticated lentils held in gene banks, as well as numerous wild relatives. They found that today's crop is the descendant of a single wild species, Lens orientalis, and domestication was centred in the Fertile Crescent, though the data doesn't allow us to pinpoint exactly where lentils were first grown as a crop.
What's more, the DNA information they've generated may help researchers identify the genetic underpinnings of traits like resistance to extreme heat and diseases.
Plant breeders are increasingly turning to the wild relatives of crops for abilities like these. Recently, potato breeders in Peru released a variety of spud armed with genes from wild potatoes that enable it to resist late blight, a devastating disease. In Morocco, a drought-tolerant wheat that's also the result of cross breeding has also just become available, and not a moment too soon: six years of drought have brought the country’s reservoirs to critically low levels.
As people are urged to replace meat in their diets with plant-based foods as a way to reduce their climate impact – the UK's Climate Change Committee argues for a 20% reduction in meat and dairy consumption by 2030 – lentils have the potential to once again take centre stage.
Source: BBC