Extracts
Researchers Revamp the Mollusks Family Tree
Seemingly simple animals like snails and squid have ransacked the genetic toolkit over the last half billion years to find different ways to build complex brains, nervous systems and shells.
Using genomics and computational approaches, an international team of researchers, including a UF neuroscientist with the Whitney Laboratory for Marine Bioscience, has reconstructed the evolutionary history of the entire phylum Mollusca. Mollusca includes more than 100,000 living species, ranging from giant squid to microscopic marine worm-like creatures.
One of the surprising outcomes of the study suggests that the formation of a complex brain in mollusks has independently occurred at least four times during the course of evolution — a finding that may prove useful to regenerative medicine scientists trying to develop new ways to help people with degenerative brain diseases.
By looking at the genomic data collected from the various classes and families of mollusks, the scientists were able to better understand the relationships between worm-like aplacophorans, slugs and snails, octopuses and squid, and a variety of shell-producing creatures.
Researchers extracted RNAs from dozens of marine organisms for sequencing and backed that information with all publicly banked data, revealing for the first time a blueprint of the molluscan life history on Earth.
The study noted that cephalopod mollusks — octopuses and squid that are known for intelligence — represent one of the earliest branches of shelled mollusks, while simpler mollusks such as clams and oysters evolved later.
Organisms like sea slugs and the octopuses are thought to be good biomedical models for understanding learning, memory and disease in people, the researchers said.