India may be the leading producer, exporter, and user of chili peppers, but these widely enjoyed spices were first cultivated by ancient farmers in Central America and South America.

This is according to University of California (UC) Davis plant scientist Paul Gepts and his team in their study published in April in the Proceedings of the National Academy of Sciences, a journal of research papers on biological, physical, and social sciences.

Evidence suggests that these Capsicum annuum (C. Annuum), which are used for culinary, medicinal and even ornamental purposes, originated in central-east Mexico, particularly in the region that extends from southern Puebla and northern Oaxaca to southeastern Veracruz, to further down south. The species has a variety of shapes and sizes of peppers, flavored from mild to hot, that range from bell peppers to chili peppers.

"Identifying the origin of the chili pepper is not just an academic exercise," said senior author Gepts in a press release. "By tracing back the ancestry of any domesticated plant, we can better understand the genetic evolution of that species and the origin of agriculture -- a major step in human evolution in different regions of the world."

In order to shed light on the theories about the popular spice, scientists determined the genetic material of the farm-raised chili peppers and searched for archaeological evidence in parts of Mexico. They also looked into the ancient languages to learn which contained words that would describe chili peppers and explored the areas where chili peppers proved suitable for growth.

"This information, in turn, better equips us to develop sound genetic conservation programs and increases the efficiency of breeding programs, which will be critically important as we work to deal with climate change and provide food for a rapidly increasing global population," Gepts added.

Christine Hastorf, a researcher at the University of California Berkeley who studies ancient humans' use of plants, reviewed the researchers' study and commended its method of data gathering. However, she cited one detail.

"[T]he weakest link is the archaeological data by far," she said in an interview with Live Science.

Hastorf noted that the study mapped only two data points as C. annuum's archaeological evidence: one from Romero Cave in the Mexican state of Tamaulipas and the other from Coxcatlán Cave, farther south, in the state of Puebla, which are both to be around 7,000 to 9,000 years old. That is based on contextual evidence.

The study was funded by the Fulbright Program, the University of California Institute for Mexico and the UC Davis Department of Plant Sciences.

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