Posted on 04/13/2018 9:30:13 AM PDT by Red Badger
A Japanese variety of sweet potato
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At some point, sweet potatoes crossed the Pacific. This much we know. As for the rest—How? When? Why?—we’re just not sure.
Or, to be more clear, some people are sure they’re sure, and others disagree.
Sweet potatoes have been at the center of a massive archaeological debate for many decades now, and a new paper in Current Biology has only stoked the flames. It uses genetic data from sweet potatoes and their relatives to establish a phylogenetic tree of their evolution, thereby demonstrating that the tubers existed in Polynesia before humans lived there.
But let’s back up for a second. Why do we care so much about sweet potatoes?
The debate about sweet potatoes is, in a way, a debate about human contact (though to be honest, it’s also definitely about the taters themselves). Before Europeans colonized much of the world, native people on both sides of the Pacific traveled fairly long distances across the ocean. South Americans made it all the way out to the Galapagos Islands, which are upwards of 620 miles off the coast of Ecuador. Pacific Islanders, including the predecessors of modern-day Samoans, Tongans, and Maoris, also managed to spread across the myriad dots of land scattered around their patch of the ocean. Those islands, especially the much-larger New Zealand and Australia, are hundreds or thousands of miles apart, which means Pacific natives regularly ventured across the ocean to explore new lands.
All these people clearly shared an affinity for the sea and serious ship-building skills. But they also shared a love of sweet potatoes. They’ve been a core crop for thousands of years, predating Columbian-era exploration. But...how? Sweet potatoes originate in South America, which is thousands of miles away from most of Polynesia.
There are three basic ways this could be possible:
South Americans ventured over to Polynesia, bringing sweet potatoes with them. Native Polynesians then either deliberately cultivated this new crop, or the seeds accidentally got fertilized and sweet potatoes began to grow naturally.
Polynesians traveled to South America, then brought sweet potatoes back with them on their return trip, presumably with the intent to plant the seeds when they got home.
Sweet potatoes, or just their seeds, floated from South America to Polynesia, no human action required.
Again: it’s still not clear which of these is true, but archaeologists have used sweet potatoes as evidence to show that Polynesians and South Americans either definitely did or definitely did not have contact for years now, with varying views on who traveled in which direction.
Apart from historical accounts from native peoples themselves, there’s mostly no evidence either way for South Americans versus Polynesians doing the carrying—there’s just evidence for human transportation versus natural spread. (The accounts themselves suggest that Polynesians may have been the ones to venture out, returning much later with tater in tow.)
One key puzzle piece: what words we use to identify the tuber. Since sweet potatoes definitely originated in South America, researchers looked at the terms for the vegetable in use by native peoples, then examined how those terms compared to the words used in Polynesia and East Asia. In South America, for example, sweet potatoes are called kuala, kumara, cumal, and other words that bear a striking similarity to the terms used in much of the Pacific Islands: umala, kumala, kumara, and so on.
Central Americans called them camote or camotil, which is nearly identical to the terms used in East Asia (kamote, camote). In the Caribbean, sweet potatoes went by Spanish words: batata or aje, which is what they’re called in New Guinea and nearby islands.
These linguistic differences don’t precisely mirror sweet potato introduction, since old names can continue to apply to new varieties (in other words, you might name a delicious new treat after something pretty similar you’re more familiar with), and we know that the tubers were actually brought west multiple times—European explorers definitely brought some over.
Sweet potato spread according to the tripartite hypothesis
Infographic by Sara Chodosh _________________________________________________________________________________________________________________
Regardless of how many introductions there were, these patterns would all necessitate direct contact between native peoples on either side of the Pacific. But not all researchers agree. Just because the words are similar doesn’t mean that the initial introduction occurred between those two people—languages evolve, after all.
The recent paper in Current Biology argues that DNA evidence suggests the Pacific Island sweet potato family branched off from the American one long before humans were sailing. Thus, the seeds or the veggies themselves must have floated their way across the ocean.
This actually isn’t as crazy an idea as it sounds. It’s the primary way that biologists think coconuts spread from island to island—the coconuts float from shore to shore. One 2008 study actually modeled the possible paths from South America to various islands, based on observing ocean currents, to see whether it was even feasible. The answer: a resounding “yep!” Over the hundreds upon hundreds of years that sweet potatoes could have traversed the ocean, seeds certainly might have floated along with currents and found new homes on other islands. It’s still uncertain whether sweet potato seeds remain viable after the minimum 120 days that the researchers estimated the journey would take, but the theory remains feasible.
Some batátas
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This new paper shows that DNA from sweet potatoes and related crops suggest that early specimens collected from Polynesia must have diverged from other tubers more than 100,000 years ago, long before humans would have been sailing across the ocean. Even the earliest estimates of people-based transportation put it circa 1000 CE, or possibly a few hundred years before that.
Previous genetic evidence had actually argued the opposite. A PNAS paper from 2013 used DNA from chloroplasts (the little organelles plants use to convert sunlight to energy) to show that sweet potato lineages have actually been recombining across islands and oceans for a long time with human help. The more recent paper argues that chloroplast DNA isn’t necessarily an accurate way to estimate phylogeny, since chloroplast genomes can mix between species in ways nuclear DNA can’t.
Whatever the reality, the archaeological debate on human contact across the Pacific will likely rage on, with sweet potatoes remaining at its heart—and in all of our hearts, really. Long live the sweet potato and all its varieties. Long live the tuber.
Lots of real small lakes or real large ponds were populated with fish from eggs pooped out by seagulls......
Why can they get to the REAL question? Marshmallows or NO Marshmallows?
No Marshmallows................for me, anyways...........
What... is the air-speed velocity of an unladen sweet potato?
Sweet Potato Pie will never be the same..........................
To me those are YAMS. A SWEET POTATO has yellow skin and yellow inside. I bake them and put lots of butter on them and eat them like a baked potato.
We peel them, cube them, boil them with butter and brown sugar, then mash them up.......................
Yeah, what you said.
The only thing I’ve ever seen that becomes even more colorful when cooked are kudzu blooms, purple also, a very strong grape scent and flavor. People make kudzu jelly from those blooms, very purple, very grape-like flavor. The purple sweet potatoes still taste like sweet potatoes but have a little something else, a little tangy to the sweet almost like fruit of some kind, not grapes though.
Not sure where this fits in the sweet potato migration theory, but the Jomon peoples of Japan where transiting the Pacific on the Black Current 14,000 years ago.
I’ve raised sweet potatoes and I don’t believe what we normally think of as seeds could cross the ocean. Slips formed from sprouted pieces of the tuber are what I always used for seed potatoes.
All of the following was found on Wikipedia.
“Yam is the common name for some plant species in the genus Dioscorea (family Dioscoreaceae) that form edible tubers. A monocot related to lilies and grasses, yams are vigorous herbaceous vines, providing an edible tuber. They are native to Africa, Asia, and the Americas.
The sweet potato (Ipomoea batatas) is a dicotyledonous plant that belongs to the bindweed or morning glory family, Convolvulaceae. Its large, starchy, sweet-tasting, tuberous roots are a root vegetable. The origin and domestication of sweet potato is thought to be in either Central America or South America.
The sweet potato was grown in Polynesia before western exploration. Sweet potato has been radiocarbon-dated in the Cook Islands to 1000 AD, and current thinking is that it was brought to central Polynesia around 700 AD, possibly by Polynesians who had traveled to South America and back, and spread across Polynesia to Hawaii and New Zealand from there. It is possible, however, that South Americans brought it to the Pacific, although this is unlikely as it was the Polynesians, and not the native South Americans, who had a strong maritime tradition. The theory that the plant could spread by floating seeds across the ocean is not supported by evidence. Another point is that the sweet potato in Polynesia is the cultivated Ipomoea batatas, which is generally spread by vine cuttings and not by seeds.”
FYI
The oldest pottery ever found was made by the Jomon People
It is my opinion that the Polynesians got their robust size from the Jomon people.
basically, none.
A yam is a sweet potato
https://www.ncsweetpotatoes.com/sweet-potatoes-101/difference-between-yam-and-sweet-potato/
Looking at that map, there is one logical deduction to make—President Trump’s 2020 opponent has a name meaning Sweet Potato.
I suppose it seems unlikely that anyone would bring the stupid things from one continent to another.
So, we can blame sweet potatoes on the poor bathroom habits of birds?
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