Genetic analysis of sweet potato testifies that it came from South America to Polynesia more than 100,000 years ago – without human intervention.
Sweet potato (Ipomoea batatas) has nothing to do with real potato. Sweet potato belongs to Convolvulaceae family, its close relatives are Ipomoea ornamental plants that are rather popular nowadays, inclusive of in Ukraine. China is the global leader as to the cultivation areas, Nigeria and Tanzania are further behind and take the second and third places, respectively.
Sweet potato’s relatives are well known as ornamental plants
One of the main mysteries of sweet potato is how it come to be present in Polynesia. After all, its homeland is South America, but it settled down in Polynesia long before the arrival of the Europeans.
There are two points of view on how this could happen. Proponents of the first point of view believe that sweet potato crossed thousands of kilometers only with the assistance of some person. Opponents of this point of view insist that this crop came to the islands of Polynesia with the help of natural forces and there we no human intervention in this process at all. The proof of the fact that sweet potato could not cross the ocean by itself will be a powerful argument suggesting that in ancient times there were some established contact between the residents of America and Polynesia.
To find out the truth about how did sweet potato find itself to be Polynesia was one of the tasks set by the team of researchers from the UK, the USA, and Peru. They have analyzed DNA of almost 200 specimens representing the sweet potato and its closest relatives, inclusive of herbaria sample of sweet potato collected by Joseph Banks in 1769, during Captain Cook’s expedition to Polynesia – this is the oldest known specimen of sweet potato from Polynesia.
Comparison of its DNA with the DNA of its closest relative from the American continent has shown that their ways parted some 100,000 years ago. Given the fact that people first landed in Polynesia much later, it is obvious that sweet potato moved across the ocean by itself – probably, on ocean currents.
It appears that the history of sweet potato does not confirm existence of any ties between the inhabitants of Polynesia and America in ancient times. But, nevertheless, it does not prove that there were no such ties at all.
Expedition of Thor Heyerdahl performed in 1947 aboard Kon-Tiki balsawood raft has proved that such ties are plausible. Research in the field of genetics and linguistics may conclusively prove or refute existence of these ties.