The Genes That Make Monarch Butterflies Basically Superheroes

Scientists have sequenced the genomes of 101 monarch butterflies to find the secret to their thousand-mile migration.

North American monarch butterflies migrate for thousands of miles every year.

Jaap de Roode

They go all the way from the northern United States and southern Canada in the summer, to Mexico in the winter.

That's a very long way!

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Basically, they're superheroes.

There are other populations of monarch butterflies who don't migrate, but permanently live in warm tropical climates.

Sonia Altizer

So what makes some butterflies want to take to the skies and others happy to stay put?

Flickr: lunasinestrellas / Creative Commons

Marcus Kronforst, University of Chicago, US, and colleagues have sequenced the genome of 101 butterflies and discovered genes that might answer that very question.

Jaap de Roode

A single amino acid makes all the difference to the migratory butterfly's muscle protein and make them much more suited to long distance flight than their home-loving cousins.

It looks like extreme distances required of monarchs selected for greater flight efficiency as they evolved.

Kronforst and colleagues also discovered much more genetic diversity in the migratory monarchs, suggesting that the tropical, home-loving butterflies evolved from a migratory species.

This is a bit weird, as migrating birds usually evolve from a species which stays put, not the other way around.

Scientists still have many questions about these butterflies, such as how they know the way on their great migration, and how they known when to leave.

Jaap de Roode

No butterfly does the migration twice, as they don't live that long, so it is still a mystery as how the newly hatched butterflies know to fly north in the spring. The butterflies even return to the same trees each year.