17/09/2025
Sharing For Awareness Purposes
Humans have 23 pairs of chromosomes — experts just found a creature with 229.
That's more than any animal on Earth.
And scientists say it could hold clues to cancer and evolution.
A tiny butterfly from the mountains of North Africa has just shattered the record for the most chromosome pairs in any known animal.
The Atlas blue (Polyommatus atlantica), an elusive species long cloaked in genetic mystery, carries an astonishing 229 pairs of chromosomes per cell—nearly ten times more than most butterflies and far beyond the 23 pairs found in humans.
While some plants exceed this number, they do so through polyploidy (multiple DNA sets). The Atlas blue, by contrast, retains just two sets—making its sheer chromosome count a biological anomaly.
Researchers believe this extreme number is the result of rapid chromosome fragmentation over roughly three million years, with autosomes repeatedly splitting at weak points in the DNA structure. Interestingly, the butterfly’s s*x chromosomes remained largely untouched, hinting at evolutionary constraints. While such chromosomal reshuffling is often harmful, the Atlas blue has flourished. Scientists say studying this butterfly’s genetic architecture could offer insights into chromosome rearrangement—processes also seen in cancer cells. Its story, published in Current Biology, offers a new frontier in understanding genome stability, evolution, and possibly human disease.
paper
"Constraints on chromosome evolution revealed by the 229 chromosome pairs of the Atlas blue butterfly." Wright, Charlotte J. et al. Current Biology, Volume 0, Issue 0
image Roger Vila
