WormClassroom

Why study C. elegans over other, more advanced organisms? The two main reasons are commonalities with other organisms, and ease of operation.

Commonalities

Organisms often share similar genes and biological principles. These commonalities enable researchers to extrapolate their findings from one organism to others.

For example, in human leukemia, large numbers of immature white blood cells (WBCs), which normally die before getting into the blood stream, are found in patients’ blood circulation. The study of Programmed Cell Death (PCD, or apoptosis) in C. elegans might help us to understand why these immature WBCs didn’t undergo PCD.

Although it is primitive and small, C. elegans shares many fundamental cellular/molecular structures and biological characteristics with more advanced organisms.

• It is eukaryotic just like us. (more about prokaryotes vs. eukaryotes)
• It has DNA as genetic materials. It produces RNA and protein as well.
• It is a multicellular organism.
• It develops from an embryo (sperm + egg) to adult using developmental processes (e.g.: differentiation & proliferation) that are also observed in other higher organisms.
• It grows, reproduces, gets old and dies.
• It has a digestive system for eating, a nerve system with a “brain” for “learning” and muscles to help it move.
• Its genome size is small (~ 10 Megabase) with about 40% homology to human (3.2 Gigabase).

Ease of Operation

With limited time and lab space, organisms that are easy to grow and store make ideal subjects.

• Its size is small. The adult worm is only 1 mm. This makes it possible to house large numbers in a laboratory setting. The total number of somatic cells in an adult worm is about 959 cells comparing to human’s trillions of cells.
• Its life cycle/span is short (about 3 days/weeks respectively). This shortens the amount of time needed for each experiment and increases the speed of scientific progress. Imagine an experimental organism with a life cycle of weeks or months (e.g. mice, primates); it would take years to gain insight into each research question.
• It is transparent. This characteristic makes it an excellent tool for studying biology questions like cell division and cell lineage (a cell’s family tree).
• It is non-parasitic free-living that feeds on bacteria (e.g. E. coli). This makes it safe for use in laboratory settings.