The Fascinating Phenomenon of Evolution Backtracking: A Case Study of Wild Tomatoes in the Galapagos Islands
The concept of evolution backtracking is not entirely novel, but witnessing it in action is a rare occurrence. Recently, researchers have documented a compelling example of wild tomatoes thriving on the black rocks of the Galapagos Islands, showcasing a species adapting by reverting genetic changes that have evolved over millions of years.
A team of scientists from the University of California, Riverside (UC Riverside) and the Weizmann Institute of Science in Israel have unveiled evidence that species can reverse changes that have occurred through the process of evolution.
Through an analysis of 56 tomato samples collected from the Galapagos, encompassing both the Solanum cheesmaniae and Solanum galapagense species, researchers delved into the production of alkaloids in these plants – toxic chemicals intended to deter predators.
Interestingly, the Solanum cheesmaniae tomatoes displayed varying alkaloids across different regions of the islands. While the plants in the eastern islands exhibited alkaloids akin to those found in cultivated tomatoes worldwide, those in the western islands showcased an older, more ancestral form of these chemicals.
Further laboratory tests and modeling pinpointed a specific enzyme responsible for this alkaloid production, with just a minor alteration in a few amino acids triggering the switch in alkaloid production.
This evolutionary reversal, known scientifically as genetic atavisms, has been observed in other instances such as experiments on chickens reverting to ancestral traits. However, the unique aspect here is the widespread propagation of critical changes throughout entire populations, suggesting significant selection pressures at play.
Remarkably, this phenomenon has occurred in the younger and more inhospitable western parts of the Galapagos islands, indicating that environmental factors may have been instrumental in driving this regression in evolutionary history.
Aside from being a captivating illustration of evolutionary dynamics, this research paves the way for advanced genetic engineering with precise control over altering plant chemistry for various benefits. Insights gained from this study could aid in developing new medicines, enhancing pest resistance, and producing safer agricultural products.
This groundbreaking research, shedding light on the intricate mechanisms of nature’s evolutionary processes, has been published in Nature Communications.
