Nav: Home

A little squid sheds light on evolution with bacteria

January 07, 2019

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.

"The Hawaiian bobtail squid has served as a model organism for studying symbiosis for over 30 years," notes Nyholm. "Having the genome will help researchers who study these interactions, as well as those studying diverse areas of biology, such as animal development and comparative evolution."

Many animals have organs that house bacteria. The human gut houses trillions of bacteria that play important roles in digestion, immune function, and overall health. Understanding how these relationships are maintained by identifying genes that help animals cooperate with bacteria lays the groundwork for furthering knowledge of the human body. The Hawaiian bobtail squid is an excellent model for identifying these genes because of its symbiotic relationships with beneficial microbes, and its use by a number of scientists to study communication between bacteria and animals.

The Hawaiian bobtail squid has two different symbiotic organs, and researchers were able to show that each of these took different paths in their evolution. This particular species of squid has a light organ that harbors a light-producing, or bioluminescent, bacterium that enables the squid to cloak itself from predators. At some point in the past, a major "duplication event" occurred that led to repeat copies of genes that normally exist in the eye. These genes allowed the squid to manipulate the light generated by the bacteria.

Another finding was that in the accessory nidamental gland, a female reproductive organ, there was an enrichment of genes that are "orphan genes" or genes that have only been found in the bobtail squid and not in other organisms.

"Squid and octopus showed very unique genome structure, unlike in any other animals," says Simakov, "corroborating previous reports of their unusual nature and complexity."

Foster notes that teasing out these unusual and complex details is directly applicable to the study of other bacteria/animal relationships.

"Microbes are major drivers of the evolution of animals and their tissues," she says. "The results of our study have helped identify the 'origin story' of those tissues that house an animal's microbes, and will help tease apart the genetic processes by which these different types of innovation can happen in animals."
-end-
P>

University of Connecticut

Related Bacteria Articles:

How bees live with bacteria
More than 90 percent of all bee species are not organized in colonies, but fight their way through life alone.
The bacteria building your baby
Australian researchers have laid to rest a longstanding controversy: is the womb sterile?
Detecting bacteria in space
A new genomic approach provides a glimpse into the diverse bacterial ecosystem on the International Space Station.
Hopping bacteria
Scientists have long known that key models of bacterial movement in real-world conditions are flawed.
Bacteria uses viral weapon against other bacteria
Bacterial cells use both a virus -- traditionally thought to be an enemy -- and a prehistoric viral protein to kill other bacteria that competes with it for food according to an international team of researchers who believe this has potential implications for future infectious disease treatment.
Drug diversity in bacteria
Bacteria produce a cocktail of various bioactive natural products in order to survive in hostile environments with competing (micro)organisms.
Bacteria walk (a bit) like we do
EPFL biophysicists have been able to directly study the way bacteria move on surfaces, revealing a molecular machinery reminiscent of motor reflexes.
Using bacteria to create a water filter that kills bacteria
Engineers have created a bacteria-filtering membrane using graphene oxide and bacterial nanocellulose.
Probiotics are not always 'good bacteria'
Researchers from the Cockrell School of Engineering were able to shed light on a part of the human body - the digestive system -- where many questions remain unanswered.
A chink in bacteria's armor
Scientists have untangled the structure of a recently discovered bacterial wall-building protein, found in nearly all bacteria.
More Bacteria News and Bacteria Current Events

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Rethinking Anger
Anger is universal and complex: it can be quiet, festering, justified, vengeful, and destructive. This hour, TED speakers explore the many sides of anger, why we need it, and who's allowed to feel it. Guests include psychologists Ryan Martin and Russell Kolts, writer Soraya Chemaly, former talk radio host Lisa Fritsch, and business professor Dan Moshavi.
Now Playing: Science for the People

#538 Nobels and Astrophysics
This week we start with this year's physics Nobel Prize awarded to Jim Peebles, Michel Mayor, and Didier Queloz and finish with a discussion of the Nobel Prizes as a way to award and highlight important science. Are they still relevant? When science breakthroughs are built on the backs of hundreds -- and sometimes thousands -- of people's hard work, how do you pick just three to highlight? Join host Rachelle Saunders and astrophysicist, author, and science communicator Ethan Siegel for their chat about astrophysics and Nobel Prizes.