HomeScienceMeet the butterfly with the most chromosomes in the World – Here’s its incredible story

Meet the butterfly with the most chromosomes in the World – Here’s its incredible story

A tiny butterfly hides a giant secret in its DNA. Scientists uncover surprising genetic twists that could change our understanding of evolution and adaptation forever.

September 12, 2025 / 11:15 IST
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Image of the Atlas blue butterfly, captured by Roger Vila, senior author of the study. (Image: Dr Roger Vila / The Institute of Evolutionary Biology)
Image of the Atlas blue butterfly, captured by Roger Vila, senior author of the study. (Image: Dr Roger Vila / The Institute of Evolutionary Biology)

Scientists have uncovered a remarkable secret about butterflies. The Atlas blue butterfly carries more chromosomes than any other. Researchers at the Wellcome Sanger Institute and Barcelona’s IBE confirmed this discovery.

What Makes the Atlas Blue Butterfly Unique?

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The Atlas blue butterfly, scientifically named Polyommatus atlantica, has 229 chromosome pairs. Most related butterflies carry only 23 or 24 pairs. Scientists sequenced the butterfly’s genome for the first time. Their study was published in Current Biology on 10 September. This research produced a gold-standard reference genome. Experts can now compare its DNA with other species.

Instead of duplicating chromosomes, the butterfly’s chromosomes split over time. Scientists found splits occurred where DNA was less tightly wound. All chromosomes, except sex chromosomes, are divided into smaller sections. This increased the number from 24 to 229 in about three million years. Evolution usually works much slower.