Scientists have found evidence that evolution has relied on the same genetic “cheat sheet” for more than 120 million years, raising the possibility that life on Earth is more predictable than once thought.
An international group of researchers led by the University of York and the Wellcome Sanger Institute focused on butterflies and moths that live in the rainforests of South America. Although these species are only distantly related, many share strikingly similar feather color patterns that act as warning signals to predators. This phenomenon is known as mimicry.
Common genes behind butterfly and moth mimicry
The researchers set out to determine which genes control common color patterns across seven distantly related species. The researchers found that despite their evolutionary distance, both butterflies and moths repeatedly rely on the same two genes, ivory and optics, to produce nearly identical warning colors.
Rather than changing the genes themselves, evolution acted on regulatory elements, often called genetic “switches,” that control when and where these genes are activated. In butterflies, these switches were modified in a similar manner across species. Scientists have discovered a surprising change in moths. It used an inversion mechanism (large chunks of DNA flips backwards) that is very similar to the strategy seen in one butterfly species.
Evidence that evolution is predictable
“Convergent evolution, where many unrelated species independently evolve the same trait, is common across the tree of life, but there are few opportunities to investigate the genetic underpinnings of this phenomenon,” said Kanchon Dasmahapatra, professor of biology at the University of York.
“Our study of seven butterfly lineages and diurnal moths shows that evolution is surprisingly predictable and that butterflies and moths have repeatedly used the exact same genetic tricks to acquire similar color patterns since the time of the dinosaurs.”
The survey results were published in a magazine PLoS Biologysuggesting that evolution is not necessarily a random process. Instead, a recurrent genetic pathway can be followed.
Why does the warning color repeat?
Professor Joanna Meyer from the Wellcome Sanger Institute added: “These distantly related butterflies and moths are both poisonous and unpleasant to the birds that try to eat them. They are very similar because if birds have already learned that a certain color pattern means ‘don’t eat us, we’re poisonous’, it’s beneficial for other species to display the same warning color.”
“Here we show that these warning colors are particularly ideal. With a highly conserved genetic basis over 120 million years, it would be very easy to evolve these same color patterns.”
What this means for evolutionary predictions
Understanding that evolution often follows established genetic pathways can help scientists predict how species will respond to environmental changes and climate change. If nature tends to reuse the same biological solutions, predicting future adaptations may be more feasible than previously thought.
