A Single Gene Affects a Butterfly's Ability to Migrate

Everyone knows about the monarch butterfly and most of us believed that it migrates south every year when it gets colder - but not every monarch butterfly migrates.  A study of butterflies, including 92 monarch butterflies, has shown that only some are migratory - the others were non-migratory.  In the study, there was a correlation between a single gene called Collagen IV alpha-1 and a monarch's ability to migrate.  Research shows that this gene affects the muscle building component and metabolism of a monarch butterfly, therefore affecting its ability to fly long distances.  When the monarchs are not migrating, there is no observed difference between those that have the gene and those that don't.

In addition to researching Collagen IV alpha-1, scientists studied the genome of migratory monarchs and determined that they did not originate in South America, but originated in North America or Mexico 1 to 2 million years ago.  The population began to grow about 20,000 years ago after the Last Glacial Maximum when milkweed became more readily available for consumption.

Lastly, researchers looked into the genes behind the orange and black coloring of the monarch butterfly.  When comparing a normal looking monarch butterfly to the black and white variety found in Hawaii, a gene called DPOGS206617 had a strong correlation with wing coloration.  This gene is similar to the one found in mice that gives their coats coloration.

This article initially caught my interest simply because the monarch butterfly brought back memories of my first grade class when we raised monarchs from the time they were caterpillars until they grew into butterflies.  I was intrigued when I read that not all monarch butterflies are migratory - I thought that all monarchs migrated!  It was interesting to learn that this is caused most likely by a single gene.