The First Potatoes
The mystery of potatoevolution has been solved—and it involved a tomato.
The potato is a globalfood staple. It was first cultivated thousands of years ago in the Andes ofSouth America before it spread worldwide starting in the 16thcentury. But its evolution has long been a puzzle, until a recent analysisfinally unraveled its origins.
Scientists say that thepotato lineage emerged approximately nine million years ago in South America,through a natural interbreeding event between a wild tomato plant and apotato-like species. This discovery is based on the genomic analysis of 450cultivated types of potatoes and 56 wild species.
This ancienthybridization event led to the appearance of the potato plant’s distinctivetuber—the enlarged structure housing nutrients underground. While the ediblepart of a tomato plant is its fruit, the potato’s value lies in thissubterranean growth. Researchers also identified two crucial genes involved intuber formation, which deepens our understanding of this crop.
Potatoes are one of themost remarkable food staples, combining versatility, nutritional value, andcultural ubiquity. Around the world, people eat potatoes using virtually everycooking method. Although stereotyped as carbohydrates, potatoes offer vitaminC, potassium, fiber, and resistant starch. They are gluten-free, low-fat, andsatiating. They are a nutrient-dense calorie source.
Resistant starch is atype of carbohydrate that resists digestion in the small intestine and fermentsin the large intestine. This means it feeds beneficial bacteria in the gut.
The scientific name formodern a potato plant is Solanum tuberosum. Its two parents wereancestors of a potato-like species now found in Peru named Etuberosum(which closely resembles the potato plant but lacks a tuber) and the tomatoplant. These two plants shared a common ancestor that lived about 14 millionyears ago, so they were able to interbreed when the hybridization eventoccurred five million years after they had diverged.
The hybridization ledto genes being reshuffled so that the lineage produced tubers, which allowedthese plants to expand into the cold, dry habitats of the rising Andes mountainchain. During the rapid uplift of the Andes, the potato plant could adapt tothe changing environment and thrive in the harsh conditions of the mountains.The tubers stored nutrients for cold adaptation and enabled asexualreproduction to counter the reduced fertility in cold conditions. Therefore,the plant could survive and rapidly expand.
The study’s findingsmay improve cultivated potato breeding to address environmental challenges thatcrops presently face. There currently are roughly 5,000 potato varieties.Potatoes are the world’s third most important food crop for humans, after rice andwheat. China is the world’s leading potato producer.
It is hard to removeall harmful mutations in potato genomes when breeding, but this study may showhow to make a potato free of harmful mutations using the tomato as the chassisof synthetic biology. It may also lead to a new crop species that would producetomato fruit above ground and potato tubers below ground.
The potato and tomatobelong to the nightshade family of flowering plants, which also includestobacco and peppers, among others. The study did not investigate the evolutionof other tuberous root crops that originated in South America such as the sweetpotato and yuca, which belong to different families of flowering plants.
Although the parts ofthe tomato and potato plants that people eat are quite different, the plantsare very similar. If you look at the flowers or leaves of these plants, theyare very similar. And if you let your potato plant produce fruits, those fruitslook like little green tomatoes. But don’t try to eat them; they are prettyyucky.
