Hybridization drove the evolution of Heliconius elevatus. – YORK UNIVERSITY
April 18 () –
Researchers have shown that an Amazon butterfly is a hybrid species, formed by two other species that They bred together almost 200,000 years ago.
The discovery, made by an international team led by scientists from the York University and Harvard University, demonstrates how the formation of new species can be more complex than science assumed.
Species are often thought of as the tips or leaves of a “tree of life.” In this model, tips divide over thousands or millions of years and new species are produced.
However, scientists now understand that the branches of the tree of life are tangled and that genes are transferred from one species to another through occasional interbreeding. In theory, this can result in the formation of a new species; a process known as hybrid speciation.
However, proving that hybrid speciation is possible in animals is a difficult task, as scientists need to show that reproduction between two species actually triggers the formation of an entirely new species that is genetically distinct from both parents.
The team of scientists, which includes researchers from several South American countries, has now found an example of a hybrid species between the colorful Heliconius butterflies of the Amazon.
In a decade-long study, researchers amassed genetic and ecological evidence showing that nearly 200,000 years ago, the ancestor of modern-day Heliconius melpomene and Heliconius pardalinus contributed parts of their genomes to produce a third distinct species, Heliconius elevatus.and that all three species now coexist in the Amazon rainforest.
Professor Kanchon Dasmahapatra, from the Department of Biology at the University of York and lead author of the study, said it's a statement: “Hybrid speciation may not be that uncommon, but it is really difficult to find convincing examples of hybrid animal species.
“In the few examples that exist, either the supposed hybrid species have only existed for a few generations and may be short-lived entities, or the hybrid species does not live alongside its parent species, which makes it difficult to know if it is actually a new species.”
Lead author Dr. Neil Rosser, a postdoctoral researcher at York University and now at Harvard University, spent several years in the Amazon crossing species involved in discovering the genetic basis of multiple traits that are important to maintain the distinctive character of a species. These traits included color pattern, wing shape, host plant preference, sex pheromones, mate choice, and flight.
Dr Rosser said: “Surprisingly, we found that in Heliconius elevatus, the parts of the genome that control these important traits are often derived from Heliconius melpomene.
This finding is key to demonstrating that hybridization drove the evolution of Heliconius elevatus, because it endowed the species with a unique combination of traits that prevent it from interbreeding with either of its parents“.
Professor Dasmahapatra added: “As the distribution of species changes rapidly due to human actions and climate change, opportunities for hybridization or mixing between species are likely to increase, which has important implications.
“This increased mixing will likely cause more genes to move between species, leading in some cases to species being swamped by genes from other species and, in other cases, possibly to the formation of new hybrid species in the future.”
The research is published in the journal Nature.
