Lampreys look like something out of a horror movie, with their pitiful mouths packed with teeth, eel-like bodies, and parasitic behavior. These “water vampires” are like an evolutionary branch point between vertebrates and invertebrates, and scientific debate about how closely related we are to these carnivorous fish is undergoing new developments.
Scientists have found some evidence that lampreys have a rudimentary sympathetic nervous system, which is thought to control the fight-or-flight response of vertebrates. For more information on the survey results, please visit The study was published April 17 in the journal Nature And it may prompt a reconsideration of the origins of the sympathetic nervous system.
lamprey It is the closest organism that scientists can study to study the ancestors of fish that evolved from vertebrates. Approximately 550 million years ago. They belong to an ancient lineage of vertebrates called. angnathids – or fish without jaws. Some scientists believe that these are the earliest group of vertebrates still alive and may provide an evolutionary window into the ancestry of all vertebrates. Other scientists have questioned this theory due to the lack of evidence for lampreys in the fossil record.
[Related: Giant prehistoric lamprey likely sucked blood—and ate flesh.]
Scientists previously thought lampreys lacked sympathetic nerves. These neurons are sympathetic nervous systemthe nervous system that targets internal organs throughout the body. intestines, pancreas, heart. The systems work together to respond to dangerous or stressful situations.It also helps maintain the body of living things. homeostasismake sure your heart keeps pumping, your digestive system keeps working, etc.
In this new researchThe researchers used lampreys to examine how developmental changes drove the evolution of vertebrate traits such as fight-or-flight. They found evidence of the type of stem cells that eventually form sympathetic neurons. The presence of these cells in lampreys may modify when the sympathetic nervous system began to evolve.
“More than 100 years of literature suggests that lampreys lack a sympathetic nervous system,” said study co-author Marian Bronner, a biologist at the California Institute of Technology. stated in a statement. “Surprisingly, we found that sympathetic neurons are indeed present in lampreys, but that they occur much later in development in lampreys than expected.”
Bronner and her team studied Neural crest cells. These are a type of stem cell unique to vertebrates that give rise to multiple cell types found throughout the body. Scientists previously thought that lampreys lacked the neural crest-derived precursors, or ancestors, that would eventually build the sympathetic nervous system.
According to Bronnerresearchers previously sympathetic nervous system Lampreys develop too quickly compared to other animals. For example, the sympathetic nervous system is formed in the first 2-3 days of a bird’s development.
[Related: You might have more in common with the sea lamprey than you realize.]
Study co-author Brittany Edens, an evolutionary biologist at the California Institute of Technology, observed neural crest-derived progenitor cells in lampreys that eventually give rise to sympathetic neurons. She found that neural crest-derived ancestors appeared much later in lampreys than in other animals. It may appear within a month after fertilization. Also, the cells do not fully mature into neurons until about 4 months of development during the fish larval stage.
it is not yet known Whether the sympathetic nervous system of lampreys controls fight-or-flight behavior as in other vertebrates. According to the teamthese findings suggest that the developmental program controlling the formation of sympathetic neurons remains in all vertebrates, from lampreys to mammals.
