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Researchers badyzing cultured cocoa genomes attributed their origin to a "unique domestication event" 3,600 years ago.
This discovery opens a new front in a long debate about when and where humans began to grow the chocolate source.
"This evidence allows us to better understand how human beings moved and settled in America," said Omar Cornejo, Washington State University Population Geneticist and author Main article on the study in Biology Communications. "It's important in itself, because it gives us time to ask questions that may be more delicate: how long did it take to make a good cocoa?" What was the strength of the domestication process? How many plants were needed to domesticate a tree? "
The study, which involved 18 scientists from 11 institutions, also revealed that cocoa domestication ended up selecting taste, disease resistance, and theobromine stimulant.
The researchers sequenced the genome of Theobroma cacao in 2010, which made it possible to define what Cornejo calls an archetype of the cocoa genome, while studying, by sequencing 200 plants, to detect the variations of the genome that can reveal the evolutionary history of the plant.
The researchers were interested in the "prince of cocoas", the Criollo – a rare, tasty product and the first to be domesticated. They discovered that it had been domesticated in Central America 3,600 years ago, but that it came from the Amazon Basin, near the present border between southern Colombia and the northern part of the country. Ecuador, from an old germplasm called Curaray. It is highly likely that it was introduced to Central America by traders, said Cornejo.
At the time, the population of this tree consisted of 437 to 2674 individuals, and most likely about 738.
The time of domestication there are 3,600 years, with margins of 2,481 and 10,903 years, is consistent with traces of theobromine found in Olmec pottery and large-scale badyzes of ancient and modern human DNA that locate colonization in the Americas there about 13,000 years old.
The researchers also benefited from support. for the badumption that domestication has a cost, because producers, by choosing plants with desirable characteristics, can eventually create plants that accumulate counterproductive genes – "deleterious mutations" – making them less fit.
The findings of the study could help identify specific gene characteristics that breeders may highlight, including yield.
"What we would like is a way to combine plants of high productivity populations – such as Iquitos – with plants of Criollo origin, while retaining all those desirable traits that make Criollo cacao the best in the world, "said Cornejo.
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