From UPSC perspective, the following things are important :
Prelims level : Comb Jellies, Neurons, Neural Network
Mains level : Not Much
- Comb jellies, or ctenophores, are marine animals with jelly-like bodies and iridescent combs.
- They represent an ancient animal lineage and have a distinct nervous system.
- A recent study published in Science examined the comb jelly nervous system and made surprising discoveries.
What are Comb Jellies?
- Comb jellies, also known as ctenophores, are marine animals that belong to the phylum Ctenophora. They are fascinating creatures with a unique and delicate appearance.
- Despite their name, comb jellies are not actually true jellyfish.
- They have a gelatinous, transparent body that is often luminescent and adorned with rows of cilia, or comb-like structures, which give them their characteristic shimmering appearance.
Findings of the new study
- The researchers aimed to investigate how nerve net neurons in comb jellies connect.
- Contrary to expectations, synapses (junctions between neurons) were absent in the nerve net.
- Instead, nerve-net neurons were continuously connected by a single plasma membrane.
Significance of ctenophores
- In the 1950s, electron microscopy confirmed the separate-cell nature of neurons connected by synapses.
- Ctenophores challenge this notion by having a syncytial nerve net, as observed in the new study.
- Ctenophores attracted attention due to their status as a potential early animal lineage.
- Whole-genome sequencing studies supported the theory that ctenophores branched off early in animal evolution.
Evolution of ctenophore nervous systems
- The evolution of ctenophore nervous systems remains unclear to biologists.
- Leonid Moroz proposed a controversial theory of independent nervous system evolution in ctenophores and other animals.
- Ctenophores exhibit a unique nervous system lacking classical neurotransmitter pathways and common neuronal genes.
- The absence of muscle-based movement and reliance on cilia might have driven the evolution of a different signal conduction system.
Questions for further research
- Researchers aim to study the development of nerve net neurons in ctenophores.
- They seek to determine if adult ctenophores retain syncytial nerve nets or develop synapses.
- The uniqueness of ctenophore nervous systems provides valuable insights into the evolution of the nervous system.
- Comparative analyses of unique animal systems like ctenophores aid in understanding neuronal function and treating disorders.
- Understanding the functional and evolutionary significance of syncytial nerve net neurons in ctenophores requires further research.
- This study serves as a crucial foundation for investigating the evolution of nervous systems in animals.
- Comparative studies on small marine creatures like ctenophores offer insights into the fundamental principles of brain function.
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