Prehistoric gars: Ancient fish DNA offers insights into evolution

ST. PAUL, Minn. (FOX 9) - If a massive 7-foot alligator gar fish being released in Louisiana looks prehistoric to you, you're basically right.

"Gars date back to the late Jurassic period," said Solomon David, an assistant professor at the College of Food, Agricultural and Natural Resource Sciences (CFANS) at the University of Minnesota and principal investigator of GarLab. "They are older than Tyrannosaurus rex."

That’s part of the reason David has been fascinated with gars since he was a kid, and has been studying them for more than 20 years. He says gars get a bad rap. 

"Rest assured they are not going to come after you," David said.

Of the seven species of gars, only two much smaller 3-6 foot species are native to Minnesota rivers and lakes: the long nose and short nose gars, plus their closest cousins, the bow fin. Gars are known to many anglers for snapping lines and not being easy to eat.

"If you feel the scales, they are rock hard, so you can’t fillet them like you would a bluegill or a walleye," David said. 

David is part of a study led by Yale University, and includes researchers from the University of Minnesota, University of Buffalo, Chinese Academy of Sciences in Beijing and the University of Southern Mississippi. Together, they have spent the last few years studding gar DNA, specifically comparing rates of molecular evolution in gars to more than 700 other organisms, most considered so-called "living fossils", ranging from turtles to sharks. 

Research recently published found gar DNA has the slowest molecular evolution rates among anything with a jaw and backbone, and basically hasn't changed in 100 million years.

"You can kind of think of it as a telephone where you start off with a message and by the end of a long chain, it’s completely different," David said. "With gars, it's correcting any changes as it goes through that process."

Now the new goal is figuring out how the gar DNA is repairing itself so well, and for so long.

"It’s just the beginning, because if we can identify that mechanism for DNA repair, we might be able to look at applications to human disease," David said.

"All the problems we have as humans, cancer, you have a problem with a mutation, maybe with your p10 gene. So this is really cool really applicable thing to humans," said Rob Blair, a professor at CFANS, and department head of the Department of Fisheries, Wildlife, and Conservation Biology.

As the library of fish specimens at the Bell Museum of Natural History has long shown, gars look the same going back several decades. 

"We can take a look at has morphology changed at all using those older specimens to the ones we collect today," said Kassie Ford, curator of fishes. 

Even a long nose gar from 1899 looks the same as those today.

"They are some of the oldest specimens we have here," said Ford.

Sealed in glass and untouchable, looking at a 125-year-old fish will only get scientists so far. It’s the evidence in the DNA David is celebrating. While work will continue collecting gars alongside the  Minnesota Department of Natural Resoruces this spring, the potential gars could offer a new perspective to what’s considered trash versus treasure.

"I think it’s neat these fish a lot of us have hated over the years might actually turn around and be very helpful to us," said David.