The Earliest Plant Genome Comes From a Stone Age Watermelon

Scientists have successfully sequenced what’ll become known as the earliest plant genome on record. While many might believe it comes from wheat or barley, it actually comes from watermelon. The plant’s seeds are believed to have been eaten during the Stone Age by sheepherders. Its location of origin is peculiar, too. The earliest plant genome comes from the Sahara desert.

How the Watermelon Seeds Were Found

The Earliest Plant Genome Comes from a Stone Age Watermelon
The watermelon seeds were found to be 6,000 years old. They were discovered in the 1990s during an archeological dig of a cave site called Uan Muhuggiag. The site is in the Sahara desert in today’s Libya.

The conditions inside the cave were perfect for the preservation of the seeds. The air inside Uan Muhuggiag is dry and salty, thus preserving the watermelon seeds almost intact. They were so well-preserved that scientists from the Royal Botanic Gardens, located in Kew, UK., were able to sequence their DNA. Their finds were published in the Journal of Molecular Biology and Evolution.

Scientists who examined the seeds showed that they came from a wild watermelon species. It’s believed to be among Africa’s oldest crops. The discovery says a lot about the cultivation and domestication of today’s species. Scientists believe that the earliest species found may have contained a revoltingly bitter pulp. It’s in stark contrast to its modern-day relative, whose name means “to eat a sweet thing.”

Other Fascinating Revelations

The discovery of the earliest plant genome also throws light on Stone Age people’s lifestyle and dietary habits. During the study, researchers have sequenced the genome of countless watermelon species, all of which are part of the Kew Garden’s collections. It was discovered that the Saharan sheepherders must have intentionally cultivated or collected the seeds.

That revelation is consistent with the oldest seeds collected in Sudan. They were found with teeth marks on them. So, the bitter-fleshed watermelon must have been part of Stone Age people’s diet, at least at some point.

What remains a mystery is when the ancient bitter fruit started to resemble today’s species. Additionally, scientists believe the species might have been cultivated primarily for its seeds.