The potato love story

I didn’t know that hybridization in plants and animals can lead to sterility in many cases. Well-known examples include the mule (a cross between a horse and a donkey) and ligers (a lion-tiger hybrid). But sometimes these chance encounters can lead to remarkable evolutionary innovations like potatoes.

Apparently, on a bright sunny day 8-9 million years ago, the roots of a tomato plant and a flowering plant called Etuberosum touched for the first time. This was no ordinary encounter. Normally, tomato plants wouldn’t find other plants that attractive, but today something was different. There was erotic love in the air, or rather, in the soil.

One thing led to another, and soon, the tomato plant and Etuberosum were engaging in furious underground sex. Fast forward some years, they had a baby that was unlike anything the world had seen before—they called their new child “potato.” Fast forward more decades and centuries, and the potato family grew, and today there are 107 wild potato species.

Solanum etuberosum

Why was this love story special?

In most hybrid love stories, the offspring are biologically neutered—they can’t have babies, but the potato was different. The tomato ancestors of potatoes made fruits above the ground, while the Etuberosum ancestors made underground stems. Potatoes inherited the right genes that allowed them to form tubers, or those underground organs that allow them to store nutrients.

So the next time you dip fries in tomato ketchup, you are engaging in an act of cannibalism.

From this fun article in The Atlantic:

Knapp and her colleagues have found in a new study, appears to be the case for the world’s third-most important staple crop: The 8-to-9-million-year-old lineage that begat the modern potato may have arisen from a chance encounter between a flowering plant from a group called Etuberosum and … an ancient tomato.

Tomatoes, in other words, can now justifiably be described as the mother of potatoes. The plant experts I interviewed about the finding almost uniformly described it as remarkable, and not only because dipping fries into ketchup just got a little more mind-bending. Potatoes represent more than the product of an improbable union; they mark a radical feat of evolution. Neither of the first potato’s parents could form the underground nutrient-storage organs we call tubers and eat in the form of sweet potatoes, yams, and potatoes. And yet, the potato predecessor that they produced could. Tubers allowed the proto-potato plant to flourish in environments where tomatoes and Etuberosum could not, and to branch out into more than 100 species that are still around today, including the cultivated potato. It’s as if a liger weren’t just fertile but also grew a brand-new organ that enabled it to thrive on a vegan diet.

From this Wiki entry:

Species are reproductively isolated by strong barriers to hybridization, which include genetic and morphological differences, differing times of fertility, mating behaviors and cues, and physiological rejection of sperm cells or the developing embryo. Some act before fertilization and others after it. Similar barriers exist in plants, with differences in flowering times, pollen vectors, inhibition of pollen tube growth, somatoplastic sterility, cytoplasmic-genic male sterility and the structure of the chromosomes. A few animal species and many plant species, however, are the result of hybrid speciation, including important crop plants such as wheat, where the number of chromosomes has been doubled.

Hat tip to Jason Kottke for the link.

By the way, I built this small aggregator that pulls articles from some of the best Substacks and blogs that I read regularly:

https://papertrails.rabbitholes.garden