{"id":476384,"date":"2026-02-18T19:39:14","date_gmt":"2026-02-18T19:39:14","guid":{"rendered":"https:\/\/www.newsbeep.com\/us\/476384\/"},"modified":"2026-02-18T19:39:14","modified_gmt":"2026-02-18T19:39:14","slug":"scientists-finally-solve-the-mystery-of-the-irish-potato-blights-origins-it-came-from-the-andes","status":"publish","type":"post","link":"https:\/\/www.newsbeep.com\/us\/476384\/","title":{"rendered":"Scientists Finally Solve the Mystery of the Irish Potato Blight\u2019s Origins. It Came From The Andes"},"content":{"rendered":"

\"Child <\/a><\/p>\n

In the mid-19th century, a microscopic invader swept across Ireland, leaving a trail of devastation in its wake. The potato blight, caused by the fungus-like pathogen\u00a0Phytophthora infestans, triggered a famine that killed over a million people and forced millions more to flee. For over a century, scientists have debated where this deadly organism first emerged. Was it the rugged Andes, where potatoes were first domesticated? Or was it the highlands of Mexico, a region teeming with similar pathogens?<\/p>\n

Now, a team of researchers claims to have settled the question. In one of the largest genetic studies of its kind, they have traced the origins of the potato blight to the Andes. The findings not only settle one of the darkest long-standing debates but also reveal a complex web of evolution, migration, and hybridization that shaped the history of one of the world\u2019s most infamous plant diseases.<\/p>\n

A Pathogen\u2019s Journey<\/p>\n

Even today, Phytophthora infestans continues to wreak havoc on potato and tomato crops worldwide, causing billions of dollars in losses each year. Learning where it originates could help scientists predict and combat future outbreaks.<\/p>\n

The debate over its birthplace has been fierce. Some researchers argued for a Mexican origin, pointing to the pathogen\u2019s sexual reproduction in the region. Others, citing genetic evidence, proposed an Andean origin. The new study, led by Allison Coomber and Jean Ristaino of North Carolina State University, brings a wealth of genomic data to the table. By 2026, this data has been integrated into global \u201cPathogen GPS\u201d systems, allowing farmers to track blight migration in real-time using handheld DNA sequencers.<\/p>\n

\"Underripe <\/a>The fungus-like organism Phytophthora infestans causes potato leaves to decay and tubers to rot. Credit: Wikimedia Commons.<\/p>\n

The team analyzed whole-genome sequences from\u00a0P. infestans\u00a0and six closely related species, including\u00a0P. andina\u00a0and\u00a0P. betacei, which are found in South America, and\u00a0P. mirabilis\u00a0and\u00a0P. ipomoeae, native to Mexico. They also included historic samples of\u00a0P. infestans\u00a0collected during the Irish Potato Famine.<\/p>\n

The results were clear. The Mexican species,\u00a0P. mirabilis\u00a0and\u00a0P. ipomoeae, formed distinct genetic groups, separate from\u00a0P. infestans. In contrast,\u00a0P. infestans\u00a0was closely intertwined with the Andean species\u00a0P. andina\u00a0and\u00a0P. betacei. These latter three species form a complex with indistinct boundaries. They\u2019re more like siblings than distant cousins.<\/p>\n

\u201cThis is how science works,\u201d said<\/a> Jean Ristaino, a co-author of the study and a professor at North Carolina State University. \u201cThere\u2019s a hypothesis, people question it, test it, present data. But over time, the evidence is really weighted in favor of the Andes, because the DNA doesn\u2019t lie. The genetics show ancestry in that region.\u201d Ristaino\u2019s team has used this \u201cancestral map\u201d to identify specific resistance genes in wild Andean potatoes that were previously overlooked.<\/p>\n

\"Fossilized <\/a>A 19th-century potato specimen from London\u2019s Kew Gardens herbarium, collected during the height of the Irish famine in 1847. Credit: Marco Thines\/Senckenberg Gesellschaft f\u00fcr Naturforschung.<\/p>\n

Historical records also point to the Andes. \u201cIn 1845, when this blight hit Europe and the U.S., people were immediately trying to figure out where it came from,\u201d Ristaino added during an interview with The Guardian. \u201cThere were reports that the disease had occurred and was known among the indigenous Andean Indians who grew potatoes.\u201d<\/p>\n

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The Andean Crucible<\/p>\n

According to the genetic analysis, the common ancestor of\u00a0P. infestans\u00a0and its Andean relatives diverged from the Mexican species around 5,000 years ago. Over time,\u00a0P. infestans\u00a0spread from the Andes to other parts of the world, including Mexico and Europe, thanks to increased overseas trade and globalization.<\/p>\n

The study also revealed surprising levels of gene flow between\u00a0P. infestans\u00a0and its Andean relatives. Migration rates between these species were much higher than those involving the Mexican species. This suggests that the Andean region is not just the birthplace of\u00a0P. infestans\u00a0but also a hotspot for ongoing evolution.<\/p>\n

One of the most intriguing findings was the blurred line between\u00a0P. infestans,\u00a0P. andina, and\u00a0P. betacei. These Andean species are so closely related that they often hybridize, creating new genetic combinations. It\u2019s like a melting pot with all these microbial species swapping genes, which could lead to new strains with different virulence traits \u2014 some of which could overcome plant resistance.<\/p>\n

Understanding where the devastating potato blight originated has major practical implications for managing this disease, which remains a global threat. <\/p>\n

Potato blight continues to wreak havoc worldwide. In Europe, fungicide-resistant and newly emerging heat-tolerant \u201cthermophilic\u201d strains have emerged, forcing farmers to seek new chemicals and methods.. New breeding and gene-editing methods could offer a long-term solution.<\/p>\n

The landscape shifted significantly in early 2026, as the European Union\u2019s new \u201cNew Genomic Techniques\u201d (NGT) regulations took effect. This policy shift, informed by the Andean origin study, allows for the expedited use of gene-edited crops. New breeding methods now focus on \u201ccisgenics\u201d\u2014transferring resistance genes from wild Andean potatoes directly into commercial varieties without using foreign DNA.<\/p>\n

\u201cWhen you know the center of origin of a pathogen, that\u2019s where you\u2019re going to find resistance to it,\u201d Ristaino said. \u201cIn the long run, the way to manage this disease is through host resistance. This work shows the focus on breeding efforts needs to happen back in the Andes.\u201d<\/p>\n

As of 2026, the first large-scale field trials of these \u201ctriple-R-gene\u201d potatoes are showing nearly 100% immunity to the blight, even in the dampest conditions.<\/p>\n

The findings appeared in the journal PLOS ONE<\/a>.<\/p>\n

This article was originally published in February 17, 2025, and has been edited to include additional information.<\/p>\n","protected":false},"excerpt":{"rendered":"In the mid-19th century, a microscopic invader swept across Ireland, leaving a trail of devastation in its wake.…\n","protected":false},"author":2,"featured_media":476385,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[34],"tags":[1155,97,1923,220466,51301],"class_list":["post-476384","post","type-post","status-publish","format-standard","has-post-thumbnail","category-health","tag-dna","tag-health","tag-ireland","tag-phytophthora-infestans","tag-potato"],"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/posts\/476384","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/comments?post=476384"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/posts\/476384\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/media\/476385"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/media?parent=476384"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/categories?post=476384"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/tags?post=476384"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}