A Roundworm May Help Us Explain How We Perceive Gravity
- Humans depend on gravity to determine orientation and maintain balance.
- Gravity is important for life to exist on Earth.
- However, the effect of gravity at the molecular level is poorly understood.
- Among animals, anatomical differences are clearly evident but there is notable conservation across different animals at the molecular level.
- Caenorhabditis elegans is appropriate for discovering genes that may help identify gravity sensing mechanism at the molecular level.
- C. elegans is a free-living nematode or roundworm that lives in temperate soil environments.
- Half of C. elegans‘ genes are similar to humans which allows genetic studies to determine genes responsible for the similar traits in humans.
- No study has been reported that C. elegans can detect the direction of gravity.
- A team in Penn Engineering led by Professor Haim Bau and Professor David Raizen did a research that may explain the mystery of gravity sensing.
- Researchers found that motile C. elegans swim in the direction of gravity while immobile C. elegans do not.
- Regardless of the density of a solution, C. elegans position themselves downward.
- Gravitaxis is not significantly affected by the animal’s gait but requires sensory cilia, dopamine transmission, as well as motility.
- Gravitaxis is the directional movement of an organism in response to gravity.
- Gravitaxis does not require genes related to body touch response.
- Gravitaxis is not mediated by passive forces like the hydrodynamics of the solutions where the C. elegans are swimming in.
- The results suggest that gravitaxis is mediated by active neural processes that involve dopamine and sensor cilia.
- C. elegans can be used as a genetically tractable system for research studies involving molecular and neural mechanisms of sensing gravity.
Chen, WL., Ko, H., Chuang, HS. et al. Caenorhabditis elegans exhibits positive gravitaxis. BMC Biol 19, 186 (2021). https://doi.org/10.1186/s12915-021-01119-9