The monarch butterfly is one of the most iconic insects in the world, best known for its distinct orange and black wings and a spectacular annual mass migration across North America. However, little has been known about the genes that underlie these famous traits, even as the insect’s storied migration appears to be in peril.
Sequencing the genomes of monarch butterflies from around the world, a team of scientists has now made surprising new insights into the monarch’s genetics. They identified a single gene that appears central to migration – a behavior generally regarded as complex – and another that controls pigmentation. The researchers also shed light on the evolutionary origins of the monarch. They report their findings Oct. 1 in Nature.
To study the genetic basis for migration, the team compared the genomes of migratory butterflies against the three non-migratory populations. They identified more than 500 genes – most of which are involved in muscle, developmental and neural function – that differed to some degree. But a single gene disparity stood out.
Migratory butterflies expressed greatly reduced levels of collagen IV α-1, a gene involved in flight muscle formation and function. The team discovered that migratory monarchs consumed less oxygen and had significantly lowered flight metabolic rates, which likely increases their ability to fly long distances compared to non-migratory butterflies.
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“Migration is regarded as a complex behavior, but every time that the butterflies have lost migration, they change in exactly the same way, in this one gene involved in flight muscle efficiency,” said Kronforst. “In populations that have lost migration, efficiency goes down, suggesting there is a benefit to flying fast and hard when they don’t need to migrate.”
Read full original article: Genetic secrets of the monarch butterfly revealed
