Summary: generally speaking, organisms are often share similar genesG 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.
1) It is eukaryotic just like us. (more about eukaryotic
2) It has DNAG as genetic materials. It produces RNAG and proteinG as well.
3) It is a multicellular organism.
4) It develops from an embryoG (sperm + egg) to adult using developmental processes (e.g.: differentiationG & proliferationG) that are also observed in other higher organisms.
5) It grows, reproduces, gets old and dies.
6) It has a digestive system for eating, a nerve system with a "brain" for "learning" and muscles to help it move.
7) Its genomeG size is small (~ 10 Megabase) with about 40% homologyG to human (3.2 Gigabase).
Ease of Operation
Along with the commonality, the following characteristics make it a good experimental organism.
1) 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 cellG in an adult worm is about 959 cells comparing to human’s trillions of cells.
2) 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.
3) It is transparent. This characteristic makes it an excellent tool for studying biology questions like cell divisionG and cell lineageG (a cell’s family tree).
4) It is non-parasitic free-living that feeds on bacteria (e.g.: E. coli). This makes it safe for use in laboratory settings.
1. Genome Size Comparison (National Human Genome Research Institute, Retrieved 12/13/04, From http://www.genome.gov/Pages/Hyperion/COURSE99/Pdf/touchman_1-20.pdf)
Cell Division: separation of a cell into two daughter cells. In higher eukaryotes, it involves division of the nucleus (mitosis) and of the cytoplasm (cytokinesis); mitosis is often used to refer to both nuclear and cytoplasmic division. (Molecular Cell Biology/Harvey Lodish [et al.] – 4th)
Cell Lineage: a pedigree of cells related through division that enable one to trace a cell’s predecessors and progeny.
Differentiation: process usually involving changes in gene expression by which a precursor cell becomes a distinct specialized cell type. (Molecular Cell Biology/Harvey Lodish [et al.] – 4th)
DNA (deoxyribonucleic acid): long linear polymer, composed of four kinds of deoxyribose nucleotides, that is the carrier of genetic information. In its native state, DNA is a double helix of two antiparallel strands held together by hydrogen bonds between complementary purine and pyramidine bases. (Molecular Cell Biology/Harvey Lodish [et al.] – 4th)
Embryo: the early developmental stage of an organism (C. elegans in this case) after fertilization and before hatching .
Gene: physical and functional unit of heredity which carries information from one generation to the next. In molecular terms, it is the entire DNA sequence – including exons, introns, and noncoding transcription-control regions-necessary for production of a functional protein or RNA. (Molecular Cell Biology/Harvey Lodish [et al.] – 4th)
Genome: total genetic information carried by a cell or organism. (Molecular Cell Biology/Harvey Lodish [et al.] – 4th)
Homologous: similarity in the sequence of a protein or nucleic acid or in the structure of an organ that reflects a common evolutionary origin. Molecules or sequences that exhibit homology are referred to as homologs. In contrast, analogy is a similarity in structure or function that does not reflect a common evolutionary origin. (Molecular Cell Biology/Harvey Lodish [et al.] – 4th)
Proliferation: the increase in the number of cells or offspring.
Protein: a linear polymer of amino acids linked together in a specific sequence and usually containing more than 50 residues. Proteins form the key structural elements in cells and participate in nearly all cellular activities.
RNA: (ribonucleic acid): linear, generally single-stranded polymer, composed of ribose nucleotides, that is synthesized by transcription of DNA or by copying of RNA. The three types of cellular RNA – mRNA, rRNA, and tRNA- play different roles in protein synthesis.
Somatic Cell: any plant or animal cell other than a germ cell or germ-cell precursor. (Molecular Cell Biology/Harvey Lodish [et al.] – 4th)