Scientists have confirmed that the Atlas blue butterfly, also known as Polyommatus atlantica, carries more chromosomes than any other animal.
Genetic sequencing revealed that this insect possesses 229 chromosome pairs, significantly more than its close relatives, which typically carry 23 or 24 pairs.
First complete genome of the Atlas blue butterfly
The research, published in Current Biology, marks the first time the butterfly’s genome has been sequenced. Experts from the Wellcome Sanger Institute and the Institute of Evolutionary Biology in Barcelona produced a gold-standard reference genome for this species.
This reference allows comparisons with other butterflies and moths. It provides new insights into how species form. They evolve and adapt over millions of years.
Chromosomes split, not duplicated
Unlike most genomic changes, the butterfly’s chromosomes did not duplicate but instead split into smaller sections. Researchers found that chromosome breakups occurred at points where DNA is less tightly wound. This process dramatically increased chromosome numbers from 24 to 229 in around three million years, a short evolutionary period.
Implications for evolution and adaptation
These chromosomal changes are thought to play a role in species formation and environmental adaptation. Splitting chromosomes could create greater genetic diversity by allowing more frequent shuffling of genetic material. Although species with many chromosomes may adapt faster, they could also face higher vulnerability due to the complexity of their genomes.
Links to human cancer research
Chromosomal rearrangements are not unique to butterflies. Similar processes occur in human cancer cells, where genome reshaping contributes to disease progression. By studying the Atlas blue butterfly’s DNA, researchers hope to uncover mechanisms that could eventually inform strategies for cancer treatment and prevention.
Conservation concerns for a fragile species
The Atlas blue butterfly inhabits the mountain ranges of Morocco and northeast Algeria. Although it has thrived for millions of years, it now faces threats from climate change, deforestation, and overgrazing. Understanding its genome may help scientists predict how the species will respond to rising temperatures and habitat destruction, supporting future conservation efforts.
Scientific perspectives on the discovery
Dr Roger Vila from the Institute of Evolutionary Biology emphasized the significance of the finding. He explained that although chromosome breakups are seen in other butterflies, they have never occurred at this scale, suggesting important evolutionary advantages.
Dr Charlotte Wright from the Wellcome Sanger Institute highlighted the collaborative effort that enabled the sequencing of this rare butterfly. She noted that exploring how chromosome splits affect adaptation could provide lessons for both conservation and human health research.
Professor Mark Blaxter, senior author at the Wellcome Sanger Institute, stressed the importance of genomic studies for understanding life on Earth. He said that sequencing extreme species like the Atlas blue butterfly allows scientists to explore both evolutionary history and future resilience.
Broader impacts of the research
This groundbreaking research not only confirms the Atlas blue butterfly’s unique genetic structure but also opens new avenues for understanding evolution, adaptation, and health. By connecting butterfly chromosome splits with processes in human cancer, scientists are bridging ecology and medicine.
Moreover, the findings underscore the importance of preserving species with extraordinary genetic features. Protecting the Atlas blue butterfly means protecting a key chapter in the story of biodiversity and evolution.