Bacteria, which are vital for the health of all animals, also played a major role in the evolution of animals and their tissues. In an effort to understand just how animals co-evolved with bacteria over time, researchers have turned to the Hawaiian bobtail squid, Euprymna scolopes.

In a new study published this week in the Proceedings of the National Academy of Sciences, an international team of researchers, led by UConn associate professor of molecular and cell biology Spencer Nyholm, sequenced the genome of this little squid to identify unique evolutionary footprints in symbiotic organs, yielding clues about how organs that house bacteria are especially suited for this partnership.

The first squid genome was sequenced by Nyholm, along with Jamie Foster of the University of Florida, Oleg Simakov of the University of Vienna, and Mahdi Belcaid of the University of Hawaii. The team found several surprises, for instance, that the Hawaiian bobtail squid’s genome is 1.5 times the size of the human genome.

By comparing the genome of E. scolopes to its cousin, the octopus, the researchers show that the common ancestor of both the octopus and the Hawaiian bobtail squid went through a major genetic makeover, reorganizing and increasing the genome size. This “upgrade” likely gave the cephalopods opportunities for increased complexity, including new organs like the ones that house bacteria.

 

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Image via University of Connecticut.