The study of lampreys has revealed surprising similarities between these primitive vertebrates and more complex ones, such as humans. Lampreys possess nerve cells responsible for the “fight or flight” response, challenging previous assumptions about the evolution of this aspect of the nervous system. This discovery places lampreys closer to complex vertebrates and suggests that the blueprint for the sympathetic nervous system has been around since before lampreys diverged from the main vertebrate line.
Sea lampreys, belonging to jawless vertebrates, were thought to lack nervous system characteristics seen in jawed vertebrates, such as the sympathetic nervous system. However, a closer examination of lamprey embryos showed the presence of sympathetic neurons that control the fight or flight response. These neurons originate from the neural crest, similar to more complex vertebrates, indicating that the lamprey’s sympathetic nervous system is rudimentary compared to mammals.
Research conducted by neuroscientists at Caltech has illuminated the development of the sympathetic nervous system in lampreys, shedding light on the evolutionary origins of this system across vertebrates. By using advanced techniques to track the genetic factors associated with sympathetic neurons, the team identified clusters of cells lining the heart and trunk of lamprey embryos that exhibit characteristics of sympathetic neurons found in other vertebrates.
Comparisons of the lamprey’s sympathetic nervous system with those of more complex vertebrates reveal key differences in the timing and size of cell clusters. Despite these differences, the presence of sympathetic neurons in lampreys suggests that this system has deep evolutionary roots and was not an innovation of jawed vertebrates. The findings challenge existing ideas about the evolution of the vertebrate nervous system and point to the ancient origins of complex neural structures seen in humans.
These results prompt further exploration into the evolutionary history of the vertebrate nervous system, encouraging researchers to investigate invertebrates to understand how sympathetic neurons evolved. By unraveling the evolutionary changes that occurred from invertebrates to vertebrates, scientists hope to gain insights into the development of complex nervous systems. This study underscores the importance of studying primitive vertebrates like lampreys to uncover the ancient origins of neural structures seen in more complex organisms.
Overall, the findings from this research highlight the remarkable evolutionary connections between primitive lampreys and more complex vertebrates, challenging conventional beliefs about the origins of the sympathetic nervous system. By unraveling the genetic and developmental pathways underlying the development of the sympathetic nervous system in lampreys, scientists have gained valuable insights into the deep evolutionary history of nervous system structures across vertebrates. Further investigations into invertebrates and ancient organisms may provide additional clues about the evolution of complex neural systems in vertebrates.
