For Krumlauf, the sea lamprey evokes a fundamental question: How did the brain evolve? The Krumlauf Lab has identified that the same genes are involved in guiding not only head-to-tail body patterning but also in building the hindbrain—the brain region controlling vital functions like blood pressure and heart rate—for both humans and sea lampreys. And both the Krumlauf and Sauka-Spengler Labs are seeking to identify first principles, or rules guiding how conserved vertebrate traits arise, like the hindbrain, in their jawless vertebrate counterparts.
Genes do not act autonomously. Rather, genes are part of interconnected networks or circuits where they interact with regulatory elements and molecular signals, turning on and off at the appropriate times to inform cell fate. Studying sea lampreys is essentially like taking a time machine into the distant past to gain insight into the circuitry we share with these ancient ancestors, and it may help us identify short circuits underlying disease.
Sea lamprey’s great invasion of the Great Lakes
Carnivorous and predatory, in the 20th century, sea lamprey’s list of attributes expanded to include “parasitic” when these Atlantic Ocean-dwelling creatures migrated inland. Manmade channels and canals allowed them to colonize, and catastrophically demolish fish populations in the Great Lakes.
Their invasion, amplified by an abundance of prey and a lack of predators, was devastating to fisheries and water recreation—so much so that multiple government initiatives were deployed to combat the crisis. Collaboratively, the Great Lakes Fishery Commission, the U.S. Geological Survey, the U.S. Fish and Wildlife Service, the Canadian government, and research partnerships established methods to control sea lamprey parasites.
Biologists even developed a lamprey-specific pesticide called a lampricide. Along with traps, nets, and careful monitoring efforts, it reduced sea lamprey populations in the Great Lakes by 90%. This successful collaboration has largely restored the swimming conditions enjoyed by fish and people alike.
However inconvenient the sea lamprey can be, they are valuable for exploring evolution.
“We have this picture of the ugly face of a sea lamprey and next to a mouse or a human, it is hard to imagine they are related,” Krumlauf said. “Yet basic parts of their brains and heads are formed in exactly the same way as ours.”