Squid, octopus, and cuttlefish are wonderfully weird creatures. Known as the soft-bodied or coleoid cephalopods, they have the most extensive nervous system of any invertebrate, complex behaviors such as instantaneous camouflage, arms studded with dexterous suckers, and other evolutionarily unique traits.
Now, Scientists dug into the cephalopod genome to understand how these unusual animals came to be. Along the way, they discovered cephalopod genomes are as weird as the animals are. Scientists from the Marine Biological Laboratory (MBL) in Woods Hole, the University of Vienna, the University of Chicago, the Okinawa Institute of Science and Technology, and the University of California, Berkeley, reported their findings in two new studies in Nature Communications.
In Albertin et al., published this week, the team analyzed and compared the genomes of three cephalopod species – two squids (Doryteuthis peace iiEuprymna scolopes) and an octopus (Octopus bimaculoides).
Sequencing these three cephalopod genomes, never mind comparing them, was a tour de force effort funded by the Grass Foundation for several years in labs worldwide.
“Probably the greatest advance in this new work is providing chromosomal-level assemblies of no less than three cephalopod genomes, all of whable for study at the MBL,” said co-author Clifton Ragsdale, professor of Neurobiology and Biology and Anatomy at the University of Chicago.
Other gene families are unusually expanded (where there are additional gene copies), such as the genes for protocadherins. These are call-adhesion molecules expressed mainly in the nervous system that seem to be involved in both the development and function of the nervous system.
“Cephalopods and vertebrates independently have duplicated their protocadherins, unlike flies and nematodes, which lost this gene family over time,” explains AlberAlbertis duplication has resulted in a rich molecular framework that ved in the independent evolution of large and complex nervous systems in vertebrates and cephalopods.”