A group of more than 100 international researchers mapped the genome of the centipede, an arthropod characterized by an elongated body and numerous legs.
The move marks the first genome sequencing of a myriapod, which includes more than 13,000 terrestrial species such as millipedes and centipedes. The researchers said that their findings offer an insight on the evolution of life on Earth.
Ariel Chipman from the Alexander Silberman Institute of Life Sciences at the Hebrew University of Jerusalem, together with colleagues, sequenced the genome of Strigamia maritime, a northern European centipede, and found that while centipedes may have numerous legs, the number of their genes is nowhere near that of humans. Centipedes have only about 15,000 genes, which is about 7,000 fewer than the genes of humans.
Chipman said that the genetic data shows show centipedes transitioned from their original habitat in the sea to becoming terrestrial creatures.
"The use of different evolutionary solutions to similar problems shows that myriapods and insects adapted to dry land independently of each other," Chipman said. "Comparing the centipede and insect genomes shows that they independently evolved different solutions to the same problem shared by all land-dwelling creatures -- that of living in dry air."
The research likewise revealed that while centipedes are closely related to insects, they do not have the olfactory gene family that insects use to smell the air, and this prompted centipedes to expand other gene families to develop their own air-sniffing ability.
"The genome provides access to many aspects of myriapod biology that have not been studied before, suggesting, for example, that they have diversified receptors for smell that are quite different from those used by insects," the researchers wrote.
The researchers also found the Strigamia maritime centipedes have lost the genes that encode light receptors and the genes that control circadian rhythm, otherwise known as the body clock. Centipedes were, however, able to keep their enhanced sensory capabilities, allowing them to recognize their environment and capture prey.
Study researcher Michael Akam said that the creatures live underground and do not have eyes, so it isn't surprising that many of the genes for light receptors are missing in these animals.
"They behave as if they are hiding from the light. They must have some alternative way of detecting when they are exposed," Akam said.
