The nematode C. elegans

The roundworm Caenorhabditis elegans is an organism that is used to systematically understand neural circuits and behavior. C. elegans has been used to discover different sensory pathways and study axon regeneration at a single neuron level. C. elegans have a comprehensive connectivity map containing around 302 neurons and 7000 synapses. 

C. elegans are an exceptional model for studying biological processes due to several reasons. Firstly, they have a three-day lifecycle which is useful for studying aging as they pass through distinct phases of life that can be observed both physiologically and genetically. Secondly, C. elegans are transparent which enables microscopy and use of laser surgery as all 959 cells in their body are accessible. Thirdly, they are genetically and molecularly tractable with multiple distinct techniques available for examining and altering their biology.

Some interesting facts about C. elegans are they hold the distinction of being the first multicellular organism to have its entire genome sequenced. Additionally, C. elegans are a type of non-parasitic free-living nematode that can be found everywhere, and they are approximately 1 mm long. They are abundant in microbe-rich environments, such as decomposing fruits and stems. Another fun fact is C. elegans have been sent into space multiple times to study the impact of microgravity on aging and muscle degeneration.

There are databases that display the anatomical features of C. elegans and their cells. Visit wormbase, wormatlas, or wormwiring for more information about C. elegans.