Analysis shows butterfly and moth genomes are mostly unchanged despite 250 million years of evolution

The most extensive analysis of its kind shows how butterfly and insect chromosomes have remained largely unchanged since their last common ancestor 250 million years ago. This stability exists despite the incredible diversity seen today in wing patterns, sizes and caterpillar shapes of more than 160,000 species worldwide.

Researchers at the Wellcome-Saenger Institute and their colleagues at the University of Edinburgh analyzed and compared more than 200 high-quality chromosome-level genomes in butterflies and moths to better understand their evolutionary history.

They further revealed rare groups of species that broke these genetic rules and underwent genetic rearrangements, including chromosome fusion — where two chromosomes join — and fission — where one chromosome splits.

facts and evidence, published I Nature Ecology and Evolution, highlighted the tight constraints governing genome evolution in these ecologically important insects. They also offer insight into the factors that have enabled selected species to defy these rules of evolution. These insights can inform and enhance. Conservation efforts By incorporating genetic information into broader conservation efforts to guide targeted strategies, monitor ecosystem health, adapt to climate change, and improve conservation.

The work is part of the Darwin Tree of Life project, which aims to sequence all 70,000 species in the UK and Ireland, and contributes to the larger Earth Biogenome project to sequence all 1.6 million named species on Earth.

The study raises broader questions about how chromosomal changes shape biodiversity over time. Researchers will continue focused efforts to sequence all 11,000 European butterfly and insect species as part of the newly launched Project Psyche.

Butterflies and moths—collectively known as Lepidoptera—represent 10% of all described animal species and are extremely important pollinators and herbivores in many ecosystems.

In this new study, Wellcome-Singer Institute researchers and their colleagues set out to understand the processes driving the evolution of the chromosomes of this highly diverse group.

They identified 32 ancestral chromosome building blocks, named “marine elements” after the 17th-century entomologist Maria Sibylla Marian, that since their last common ancestor 250 million years ago, most butterflies and are maintained across insect species.

Barring an ancient fusion event between two chromosomes that led to the 31 chromosomes seen in most species today, the chromosomes of most extant species correspond directly to these ancestral merian elements. The team found that not only were the chromosomes incredibly stable, but so was the order of genes within them.

The team found some species with minor changes, mainly involving the fusion of short autosomes and sex chromosomes. This highlights the role of chromosome length as a driver of evolutionary change.

However, the researchers discovered a group containing a rare subset of species such as blue butterflies — Lysandra — and cabbage white butterflies — Pears — that defy these constraints of genome structure. These groups underwent extensive chromosomal rearrangements, including chromosome breakage, and large-scale rearrangements by fission and fusion.

This work adds to the understanding of the factors that lead to genetic diversity within these insects. It can guide conservation and conservation efforts for specific species facing unique challenges and environmental changes. Climate change.

“The chromosomes of most butterflies and moths alive today can be directly traced back to 32 ancestral Merian elements that existed 250 million years ago,” said Charlotte Wright, first author of the study at the Wellcome Sanger Institute. It is surprising that despite the wide diversity of species, their chromosomes are remarkably conserved.”

“This challenges the idea that stable chromosomes can limit species diversity. In fact, this feature may be a basis for building diversity. We hope to find clues in rare groups that have followed these principles.” What has been avoided.”

Professor Mark Blaxter, senior author of the study and head of the Tree of Life Program at the Wellcome Sanger Institute, said, “Studies like this, which allow us to understand these evolutionary processes, are only possible with measures like Darwin’s tree. LIFE project that produces high-quality, publicly available genome assemblies. We are expanding these efforts in Project Psyche, which aims to sequence all 11,000 butterfly and insect species in Europe with colleagues across the continent. to give.”

“As important pollinators, herbivores, and food sources in various ecosystems, as well as powerful indicators of Ecosystem healthA deeper understanding of butterfly and insect biology through Project Psyche will inform future studies on adaptation and hypothesis for biodiversity conservation.”