Over 99% of Modern Potatoes Descend From Chilean Ones: The Lineage Chiloé Still Grows

Some inheritances carry no surname. They travel in a sack, get buried in a furrow and, a couple of centuries later, sit on tables all over the world without anyone asking where they came from. The potato is one of those inheritances. If you ask where potatoes come from, the honest answer is Peru: that is where the crop was domesticated, and it was domesticated only once. But the story has a second chapter, and that chapter is ours. According to the University of Wisconsin-Madison, more than 99% of modern potato varieties descend from potatoes that once grew in the lowlands of south-central Chile.

Scale helps to size this up. The Food and Agriculture Organization of the United Nations (FAO) describes the potato as the world's leading non-grain food crop: global production hit a record 383 million tonnes in 2023, and it is grown in more than 100 countries. The 99% figure is not about those tonnes. It is about varieties, meaning the types of potato planted today and who their ancestors are. And there the comparison is sharp. Peru holds the domestication, established in 2005 by a genetic study from David Spooner and his team. Chile holds the lineage that went on to fill the rest of the map. Europe saw the same thing on a smaller scale: the Andean type was predominant in the 1700s and was still being grown as late as 1892, but the Chilean potato was already there in 1811 and ended up as the predominant one.

Put another way: if we lined up one hundred modern potato varieties, the kind planted today, the American university's count would look like this.

Barely one cell is left unpainted, and the source says not even a full one: it speaks of more than 99%. The grid deserves a careful read, because the figure is precise about what it claims and what it does not. It claims ancestry: modern varieties are direct descendants of potatoes from the lowlands of south-central Chile. It does not claim the potato was born here, or that every potato harvested on Earth is Chilean. It is a number about kinship, not about production. Even read with that caution it remains enormous: the crop was domesticated in the Peruvian Andes, yet the version the world adopted is the one that passed through our soil.

This is not the first time one of our plants ended up belonging to everyone. It happened with the strawberry sold worldwide today, which also traces back to Chile. The difference is that the potato had to wait for DNA to speak, because for nearly eighty years the idea was only a hypothesis.

What 49 Herbarium Samples Said About 1811

The hypothesis was Russian and dated from 1929: scientists from that country proposed that the European potato had a Chilean origin. It sounded reasonable, but nobody could prove it. Over time an alternative explanation took hold, under which the Chilean potato only reached Europe as a response to late blight, a potato disease that appeared on that continent in the 19th century. Two accounts, no direct proof.

To settle it, Mercedes Ames and David Spooner, in work released by the University of Wisconsin-Madison and by the Agricultural Research Service of the United States Department of Agriculture (USDA-ARS), went looking where nobody had looked: in herbaria. A herbarium is a collection of dried, pressed and dated plants, and Europe's herbaria hold potatoes grown centuries ago. According to the university, Ames gathered material from 64 potato plants grown between 1700 and 1910 and successfully extracted DNA from 49. In those samples she searched for one very specific mark: a deletion, meaning a missing fragment, in the plastid DNA, the genetic material of plastids, the compartments of the plant cell where photosynthesis takes place. That gap is characteristic of the Chilean potato. If the mark showed up in a dried plant with a date on it, the Chilean potato was in Europe that year.

The result, published in 2008 in the American Journal of Botany, put the whole chronology in order. The Andean type was predominant in the 1700s. The Chilean potato appears in 1811. And it became the predominant type long before the blight. The USDA-ARS release summed it up in one sentence:

"While the genetic makeup of today's European potato is indeed Chilean, the landrace was introduced to Europe 34 years before late blight first struck."

Thirty-four years. That number takes the old explanation apart: our potato did not enter Europe as an emergency replacement, it arrived earlier and stayed. The Russian hypothesis of 1929 had to wait 79 years for its proof, and the proof was sitting in museum drawers. The full sequence fits in seven milestones.

Read from top to bottom, the line shows a handover. For decades the two lineages shared European soil: the Andean one was still being grown in 1892, 81 years after the first Chilean record. The last milestone is the one that closes the case. In 2019, a team published in the journal Nature Ecology & Evolution the genomes of 88 individuals, among them landraces, modern cultivars and historical herbarium samples, including specimens collected by Charles Darwin during the voyage of the Beagle. It was no longer a single marker, it was the whole genome. And the result pointed the same way: European potatoes collected between 1650 and 1750 were closely related to Andean landraces, and after their introduction to Europe they admixed with Chilean genotypes.

There is something very typical of science in this story: the decisive evidence had been stored for generations, waiting for the right tool. The same happened to us with the global drug that came out of a soil sample from Rapa Nui: the valuable thing was already there, and someone had to learn how to read it.

Chiloé, One of 6 Pilot Sites Worldwide Where That Lineage Lives On

The underlying question remains: why did the Chilean lineage win and not the Andean one, which was the original and the first to reach Europe? The answer lies in light. The potato forms its tubers, the part we eat, in response to day length. In its Andean home range it does so under short days, as the 2019 study describes. Europe and North America sit at latitudes where the growing season brings long days. That is where the work published in 2017 by Hardigan and colleagues in the Proceedings of the National Academy of Sciences (PNAS) comes in: migration from the Andes to coastal Chile yielded a long-day-adapted group, called Chilotanum, which later contributed much of the genetic background of commercial cultivars throughout the world. The same study identified 2,622 genes as under selection and found that only 14% to 16% of them are shared by North American and Andean cultivars. They are relatives, but selection took them down different roads.

Side by side, the two lineages tell opposite stories on three fronts: where they arise, how they respond to light and what place they hold in today's potato.

The table shows that the Chilean advantage was never about seniority. It was about fit. The Andean lineage holds the origin, and nobody takes that away. Ours came later, derived from it, but with the long-day adaptation that the latitudes of Europe and North America demanded. In agriculture, matching the environment weighs more than getting there first.

And Chiloé? The sources behind the 99% speak of the lowlands of south-central Chile, not of one island in particular, and that precision should be respected. The bridge to Chiloé comes from another study, published in 2014 in the journal Plant Genetic Resources by a team from INRA, in France. They compared 350 worldwide varieties or breeders' lines with 30 Chiloé Island landraces, using genetic markers, and found no clear genetic structure separating the modern group from the Chiloé potatoes. In plain terms: the potatoes we grow in Chiloé and the ones planted across the rest of the world are still, genetically, the same family. The lineage was not left filed away in a herbarium. It is still in the ground.

That heritage has formal recognition. FAO runs a programme called Globally Important Agricultural Heritage Systems (GIAHS, or SIPAM by its Spanish acronym), devoted to territories whose traditional agriculture matters to the whole world. According to Chile's Ministry of Agriculture, Chiloé was one of the 6 pilot sites of the initiative worldwide, and FAO recognised Chiloé agriculture as a site of the programme in 2011. Six on the entire planet. One is ours.

And what gets recognised gets safeguarded. On 2 June 2025, Chile's Agricultural Research Institute (INIA) opened the Potato Germplasm Bank in Osorno. Germplasm is the living material, seeds or tissue, that allows a variety to be conserved and reproduced. The bank receives a collection of more than 450 accessions of native potatoes (an accession is each registered and identified sample within the collection) and provides for cryopreservation, meaning storage at ultra-low temperatures, with a 100-year horizon. Osorno lies in the same Los Lagos Region as Chiloé, so scientific custody and traditional farming operate in the same territory.

That is why this story can be told without inflating it. We did not invent the potato: that credit is Andean, and it is right that the record says so. Ours is something else. It is having been the land where that crop adjusted to long days, having kept growing that lineage in Chiloé, having become one of FAO's 6 pilot sites in the world and having built in Osorno a bank designed for 100 years. That is where what we sow meets what we plan for the long term. Back home we have a word for this, bacán, the Chilean word for something that earns your admiration. More than 99% of modern potato varieties carry that mark, according to the University of Wisconsin-Madison, and when the data speaks this clearly, there is only one thing left to say: we are bacán.