Heliconius melpomene genome sequenced: butterflies crossbreed to survive

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Lev Bely, 18.05.2012 16:43

More than 70 scientists from 9 institutions including The Smithsonian Tropical Research Institute, sequenced the genome of the Postman butterfly (Heliconius melpomene), a favorite one among collectors and researchers since the very Victorian times. The study results were published in the reputed “Nature” journal.

Panama's Heliconius melpomene genome explains the incredible variety of tropical butterflies colors and patterns. Butterflies of Heliconius genus are of loathsome taste and predators are aware of that thank to insects' bright colors. So did some other species eventually copy their wing patterns. The question is, how?

While exploring the genome sequence, researchers found out that different butterfly species copied wing patterns by exchanging genes what actually happened very rare, especially in animals. Some wild species could crossbreed but their offspring is often non-reproductive. Hybrids happen to get useful genes that help them to adapt to changing conditions, so Heliconius hybrids gain more apposite wing patterns that increase their survival rates.

Kanchon Dasmahapatra, the lead author of the study and a former Smithsonian fellow who worked with Jim Mallet at University College London, notes: “What we discovered is that one butterfly species can gain its protective colour pattern genes ready-made from a different species by hybridizing with it — a much faster process than having to evolve one’s colour patterns from scratch.”

Few more genes in the sequence also surprised researchers. Butterflies of this genus have been always considered as “visual” insects, yet they appear to have a rich array of genes for smelling and sensing chemicals in their environment, what may indicate some connection between perception and the origins of new species. The analysis carried out at the University of California by co-author Adriana Briscoe, showed that butterflies in fact have a wider array of genes responding to chemical communication than moths, who are led by chemical signals for finding partners to mate and host plants.

This study starts off a new period in genome biology whilst it's also a headway for the Smithsonian Institute to a better understanding of the world's biodiversity and ways of its saving. Nowadays low-cost genetic sequencing allows researchers to work in small groups or even individually, and to sequence entire genomes what's formerly been barely possible but in major labs supported by government funds.

“Assembling a genome from scratch is still hard work: think Humpy-Dumpty,” said Owen McMillan, geneticist and Academic Dean at the Smithsonian Tropical Research Institute, “but it is getting easy, inexpensive, and is transforming how we do science. At the core, having a reference genome opens up new research possibilities and reveals previously unimagined connections”.

Smithsonian Science, http://smithsonianscience.org

Photo: a part of the Heliconius melpomene wing, Mathieu Joron, http://www.eurekalert.org

Heliconius melpomene male courting a female