A Shocking Twist in Evolution

On the volcanic islands of the western Galápagos, evolution seems to be taking a surprising turn. Wild tomato plants are rediscovering a toxic concoction of chemicals that vanished from their lineage millions of years ago.

To everyone's astonishment, these tomatoes are starting to produce molecules reminiscent of eggplants rather than contemporary tomatoes. Scientists at the University of California, Riverside, are diving into this strange case of what they are calling "reverse evolution."

Tomatoes Walk Back in Time

While evolution is typically seen as a one-way street leading to improvements, these Galápagos tomatoes are seemingly looping back to ancient traits. Historically, once an evolutionary path is taken, regaining lost traits is considered highly unlikely—until now.

Adam Jozwiak, a molecular biochemist and the study's lead author, expressed disbelief, stating, "It’s not something we usually expect, but here it is, happening in real time on a volcanic island."

Chemical Revelations from the Past

This research revealed that these unique tomatoes are synthesizing not just any alkaloids, but an ancient version, different from those found in today’s cultivated varieties.

Over 30 tomato samples were collected across the islands. The older eastern islands produced familiar modern alkaloids, while the younger western islands shocked researchers with a different molecular structure—one found only in long-ago tomato ancestors and their eggplant relatives.

Nature's Tough Love: The Catalyst

So why this surprising evolutionary twist? Researchers propose the harsh conditions of the newer islands could be urging the plants to revert to a more robust form of chemical defense. Jozwiak suggested, "The ancestral molecule may provide better protection in these tougher conditions."

The Mechanics of Revival

A slight modification in enzyme chemistry—four amino acid changes—has transformed the way these tomatoes construct their defensive alkaloids. The study even replicated these ancient alkaloids in tobacco plants by inserting the relevant enzyme genes.

The Potential Implications of Reverse Evolution

Dubbed a bold claim, this idea of reverse evolution in Galápagos tomatoes opens the floor for exciting discussions. Rare examples exist in nature, but the precise genetic evidence makes this instance particularly compelling. Acknowledging skepticism, Jozwiak confirmed, "The mechanisms are there. It happened."