Science and Tech

From white to black

On the one hand, there was a team of researchers from the University of Liverpool in England, who studied the British moths for four years trying to identify the genes that allowed these insects to adapt to new conditions in order to survive.

Before the Industrial Revolution, peppered moths were white, speckled with black, but they subsequently turned completely black. The tree bark that was their habitat had turned dark due to soot adhering to it, making it imposible for the light-colored moths to camouflage themselves, and making them easy prey for predators.

“Thus, the so-called carbonaria (black) moths, which could better camouflage themselves, became more abundant. This is an example of natural selection, where the organism that survives is that which is better equipped to face changing environmental conditions,” explains Carolina Pardo, principal professor at El Rosario and expert in evolutionary genetics.

Pardo participated in the consortium, on the team that studied the application of natural selection in the specific case of the South American butterflies. The consortium included scientists from Cambridge, Sheffield, and York Universities in the United Kingdom; Harvard University in the United States; the National Museum of Natural History in France; the Smithsonian Institute for Tropical Research in Panama; the University of Adelaide, in Australia, and the Department of Biology of the Faculty of Natural Sciences and Mathematics of the Universidad del Rosario in Colombia.

“This team discovered that the cortex gene, as opposed to how it worked in the moths, had enabled the butterflies to take on bright colors to attract mates and warn predators of their toxicity,” explains Mauricio Linares, Dean of the Faculty of Natural Sciences and Mathematics at the Universiad del Rosario and director of the research group on Evolutionary Genetics, Phylogeography, and Ecology of Neotropical Biodiversity, in which Pardo and Salazar both participate. He adds that the two projects provided evidence that despite having been separated from a common ancestor 100 million years ago, the moths and butterflies use the same genetic region to adapt in different fashions to their environments in order to survive.
 

Evolution over hundreds, not millions of years

Another finding surprised the researchers in both teams. While the cortex gene enabled the adaptation of the butterflies millions of years ago, in the case of the British moths it did so only 200 years back. According to scientists at the University of Liverpool, the change took place in 1819.

Furthermore, as British media pointed out, white moths with black markings are increasing in frequency today, since pollution, and the soot it left on trees, has decreased.

“This shows us that evolutionary changes can occur over very short periods of time. We don’t necessarily have to wait thousands or millions of years to see them. It is also evidence that many environmental changes generated by humans can affect nature,” adds Salazar. The Dean of the Faculty of Natural Sciences and Mathematics underlines that having found that the same gene is used in different ways by different organisms to adapt to such dissimilar ecological environments may teach us an evolutionary principle.
 

“It may take a long time, often millions of years, for evolution to generate biological molecules that perform certain complex functions.

But once evolution ‘nails’ a useful and successful molecular structure, it is easier to slightly modify the gene that produces it so that it will perform new functions and allow new adaptations to begin, rather than wait millions of years for the appearance of another molecule that will perform a similar function,” explains Linares.

For this reason, he affirms that is very important to continue this research. “It gives us the opportunity to clarify the molecular and functional details of how the cortex gene works, and helps us understand the evolutionary origin of these biological adaptations, not only in insects but also in human beings, since very similar functional and regulatory mechanisms may be behind many of the biological marvels that characterize us, including many of our adaptive systems and organs,” he says.