Nov 4, 2022 05:59 PM
https://www.smithsonianmag.com/science-n...180981008/
EXCERPTS: About 6,000 years ago, a band of herders corralled their sheep into a cave in northern Africa. As the group settled in for the night, they probably munched on seeds, gossiped and gazed at the cave walls, which were adorned with paintings of spear-wielding hunters and dashing prey. The weary nomads wouldn’t have noticed when some of the seeds fell to the ground.
In most cases, the snacks would have decomposed, their story ended. But the cave’s dry, salty air preserved the remains like cured meat. Millenniums later, the seeds resurfaced with other botanicals, bones and artifacts when 20th-century archaeologists excavated the site, known as Uan Muhuggiag, in the Sahara of present-day Libya.
And now, a team of scientists has sequenced one of the seed’s DNA—the oldest-yet genetic code recovered from a plant. The genome reveals the seeds belonged to a 6,000-year-old wild watermelon, which probably had sickeningly bitter pulp. It seems Saharans first consumed watermelon seeds, long before the fruit evolved into the sweet, domesticated crop grown today on farms worldwide. The findings, recently published in Molecular Biology and Evolution, provide clues for archaeologists piecing together the history of watermelon domestication. And understanding the fruit’s past diversity could help genetic engineers design future melons.
[...] Decades ago, Dorian Fuller put forth the idea that savory seeds, rather than sweet pulp, initially attracted foragers to certain wild melons and gourds. “The seed is high in edible fats, and it’s storable and transportable,” he says. “We often think of watermelon seeds or pumpkin seeds as snacks, but there’s no reason why in some cases they might be cultivated in part primarily for the seed.”
Yet, archaeologists have struggled to discern how early cultivators used the fruit. Some of the oldest evidence for watermelon eating comes from Egypt during the time of the pharaohs. In a 4,300-year-old tomb, a mural depicts a green-striped, oblong fruit that looks like Citrullus lanatus. Because the melon rests on a table laden with grapes and other sweet fruits, the scene suggests Egyptians ate watermelon for its pulp by this time. However, a millennium later, the 3,300-year-old tomb of the pharaoh Tutankhamun included 11 baskets stocked with a mix of jujube and watermelon seeds.
“I don’t think it was expected that King Tut would have planted these watermelons,” says Susanne Renner, a plant biologist at the University of Munich in Germany. More likely, Renner explains, the king was supposed to eat the seeds as he journeyed to the afterlife.
[...] botanists thought only four species of watermelon existed and that the sweet one, Citrullus lanatus, was domesticated in southern Africa...
[...] Chomicki ... discovered the sweet watermelon type specimen was not a sweet watermelon. [...] Native to deserts of southern Africa, citron melon is a relative of Citrullus lanatus, but it’s not the closest cousin. The sweet crop shares more DNA with wild watermelons growing in other parts of Africa, Chomicki and Renner reported in a 2015 study.
“Until our paper … everybody, all the texts and web pages and so on, said the [domesticated] watermelon was from South Africa,” says Renner.
Through similar studies, analyzing modern and centuries-old specimens, the researchers discovered that sweet watermelon’s closest relative sprouts in Sudan today. So northeast Africa is a good guess for where its domestication occurred. But scientists can’t definitively pinpoint the area because the habitats suitable for watermelon may have shifted as Africa’s environment changed across the past 10,000 years. Also, finding the crop’s closest kin doesn’t answer why past humans started cultivating the plant.
[...] The scientists ... obtained seeds from a site along the Nile River in present-day Sudan. Some 3,000 years ago, the spot held a desert encampment near a larger town ruled by Egyptian pharaohs...
The team managed to extract DNA from both sites’ seeds. “It’s just amazing,” says Renner. The Uan Muhuggiag genome lacked key mutations that determine sweetness and red color. “It was not a watermelon as we know it now,” she explains.
The fruit likely had a bitter, white interior. Considering the bite-like cracks, it’s probable Saharans munched these seeds. The pulp’s fate remains a mystery. Perhaps the cave visitors discarded the unpalatable stuff, fed it to livestock or cooked it in a stew, [...] The seed from Sudan didn’t yield the stretch of DNA necessary to check for sweetness and color mutations. But both seeds offered enough genetic code to compare them to more recent melons...
[...] The archaeological seeds from Libya and Sudan contained stretches of DNA that matched different modern watermelons. The Uan Muhuggiag seed was genetically closest to egusi watermelons eaten for their seeds today in West Africa. The findings support the idea that past Saharans enjoyed bitter fruits for their tasty seeds... (MORE - missing details)
EXCERPTS: About 6,000 years ago, a band of herders corralled their sheep into a cave in northern Africa. As the group settled in for the night, they probably munched on seeds, gossiped and gazed at the cave walls, which were adorned with paintings of spear-wielding hunters and dashing prey. The weary nomads wouldn’t have noticed when some of the seeds fell to the ground.
In most cases, the snacks would have decomposed, their story ended. But the cave’s dry, salty air preserved the remains like cured meat. Millenniums later, the seeds resurfaced with other botanicals, bones and artifacts when 20th-century archaeologists excavated the site, known as Uan Muhuggiag, in the Sahara of present-day Libya.
And now, a team of scientists has sequenced one of the seed’s DNA—the oldest-yet genetic code recovered from a plant. The genome reveals the seeds belonged to a 6,000-year-old wild watermelon, which probably had sickeningly bitter pulp. It seems Saharans first consumed watermelon seeds, long before the fruit evolved into the sweet, domesticated crop grown today on farms worldwide. The findings, recently published in Molecular Biology and Evolution, provide clues for archaeologists piecing together the history of watermelon domestication. And understanding the fruit’s past diversity could help genetic engineers design future melons.
[...] Decades ago, Dorian Fuller put forth the idea that savory seeds, rather than sweet pulp, initially attracted foragers to certain wild melons and gourds. “The seed is high in edible fats, and it’s storable and transportable,” he says. “We often think of watermelon seeds or pumpkin seeds as snacks, but there’s no reason why in some cases they might be cultivated in part primarily for the seed.”
Yet, archaeologists have struggled to discern how early cultivators used the fruit. Some of the oldest evidence for watermelon eating comes from Egypt during the time of the pharaohs. In a 4,300-year-old tomb, a mural depicts a green-striped, oblong fruit that looks like Citrullus lanatus. Because the melon rests on a table laden with grapes and other sweet fruits, the scene suggests Egyptians ate watermelon for its pulp by this time. However, a millennium later, the 3,300-year-old tomb of the pharaoh Tutankhamun included 11 baskets stocked with a mix of jujube and watermelon seeds.
“I don’t think it was expected that King Tut would have planted these watermelons,” says Susanne Renner, a plant biologist at the University of Munich in Germany. More likely, Renner explains, the king was supposed to eat the seeds as he journeyed to the afterlife.
[...] botanists thought only four species of watermelon existed and that the sweet one, Citrullus lanatus, was domesticated in southern Africa...
[...] Chomicki ... discovered the sweet watermelon type specimen was not a sweet watermelon. [...] Native to deserts of southern Africa, citron melon is a relative of Citrullus lanatus, but it’s not the closest cousin. The sweet crop shares more DNA with wild watermelons growing in other parts of Africa, Chomicki and Renner reported in a 2015 study.
“Until our paper … everybody, all the texts and web pages and so on, said the [domesticated] watermelon was from South Africa,” says Renner.
Through similar studies, analyzing modern and centuries-old specimens, the researchers discovered that sweet watermelon’s closest relative sprouts in Sudan today. So northeast Africa is a good guess for where its domestication occurred. But scientists can’t definitively pinpoint the area because the habitats suitable for watermelon may have shifted as Africa’s environment changed across the past 10,000 years. Also, finding the crop’s closest kin doesn’t answer why past humans started cultivating the plant.
[...] The scientists ... obtained seeds from a site along the Nile River in present-day Sudan. Some 3,000 years ago, the spot held a desert encampment near a larger town ruled by Egyptian pharaohs...
The team managed to extract DNA from both sites’ seeds. “It’s just amazing,” says Renner. The Uan Muhuggiag genome lacked key mutations that determine sweetness and red color. “It was not a watermelon as we know it now,” she explains.
The fruit likely had a bitter, white interior. Considering the bite-like cracks, it’s probable Saharans munched these seeds. The pulp’s fate remains a mystery. Perhaps the cave visitors discarded the unpalatable stuff, fed it to livestock or cooked it in a stew, [...] The seed from Sudan didn’t yield the stretch of DNA necessary to check for sweetness and color mutations. But both seeds offered enough genetic code to compare them to more recent melons...
[...] The archaeological seeds from Libya and Sudan contained stretches of DNA that matched different modern watermelons. The Uan Muhuggiag seed was genetically closest to egusi watermelons eaten for their seeds today in West Africa. The findings support the idea that past Saharans enjoyed bitter fruits for their tasty seeds... (MORE - missing details)