For the first time, researchers have sequenced the full genome of a centipede and have found that having so many legs does not translate extra genes.
According to Reuters, a multi-institutional team of 106 international researchers collaborated on the study, published in the journal PLOS Biology. The team analyzed the Strigamia maritima, a venomous centipede from northern Europe.
"This is the first myriapod and the last of the four classes of arthropods to have its genome sequenced," study co-author Dr. Stephen Richards, an assistant professor in the Human Genome Sequencing Center at Baylor University, said in a press release. "Arthropods are particularly interesting for scientific study because they diverged into more species than any other animal group as they adapted in many ways to conquer the planet. The genome of the myriapod in comparison with previously completed genomes of the other arthropod classes gives us an important view of the evolutionary changes of these exciting species."
Despite what their name might suggest, no centipede has 100 legs and typically have 45 to 51 pairs of legs, though it is always an odd number of pairs.
"From fossil evidence, we know the myriapods are one of three independent arthropod invasions of the land (from the sea), in addition to the insects and spiders. So they had to find a way to smell chemicals in air, rather then taste them in water. The team identified large gene expansions of the gustatory (taste) receptors suspected to fill the olfactory role that olfactory (smell) receptors play in insects," Richards said. "This is a nice example of parallel evolution where different group of genes expanded, providing a different solution to the same problem."
They also learned that S. maritime have about 15,000 genes, which humans outnumber by some 7,000, and that the centipede lost its eyes more than 200 million years ago.
"Strigamia (centipedes) live underground and have no eyes, so it is not surprising that many of the genes for light receptors are missing, but they behave as if they are hiding from the light. They must have some alternative way of detecting when they are exposed," study co-author Dr. Michael Akam, of the University of Cambridge. "It's curious, too, that this creature appears to have no body clock - or if it does, it must use a system very different to other animals."
