An unassuming butterfly called the Atlas blue has been confirmed to have the greatest known number of chromosome pairs of any animal.

The elusive species ( Polyommatus atlantica ), which is native to the mountains of North Africa, possesses as many as 229 pairs per cell.

To put that in perspective, most other butterflies have 31 or 32 pairs. We humans have 23 pairs in the nucleus of each of our cells.

Some plants have more chromosomes than the Atlas blue, like the Adders-tongue fern ( Ophioglossum reticulatum ) with 720 chromosomes per cell. But that's because they can have up to ten sets of DNA – the Atlas blue has but two.

"When we set out to start to understand evolution in butterflies, we knew we had to sequence the most extreme, and somewhat mysterious, Atlas blue butter

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