Raible is member of both Arendt's group and a second EMBL lab, that of Peer Bork, whose specialty is analyzing genomes by computer. "Human genes are typically more complex than those of flies," explains Bork.
"Classically-studied species like flies have far fewer introns, so many scientists have believed that genes have become more complex over the course of evolution. There have already been speculations that this may not be true, but proof was missing. Now we have direct evidence that genes were already quite complex in the first animals, and many invertebrates have reduced part of this complexity."
Not only are the introns there ?the team also discovered that their positions within genes have been preserved over the last half a billion years. "This gives us two independent measurements that tell the same story," Raible explains. "Most introns are very old, and they haven't changed very much in slowly-evolving branches of life, such as vertebrates or annelid worms. This makes vertebrates into something like 'living fossils' in their own right."
The discovery that Platynereis also represents a slowly-evolving branch of animal life has important implications for the study of humans. "We've already learned an incredible amount about humans from studies of the fly," Arendt says. "The marine worm might well give us an even better look at important conserved processes. Anothe
Source:European Molecular Biology Laboratory