INTRODUCTIONCaenorhabditis elegans are nematodes that feed on Escherichia coli. and live in free soil. C. elegans is a good model organism because it is small, has a short lifespan, reproduces quickly and has many offspring, and is easy and inexpensive to grow in the laboratory. , that there is visible phenotypic differentiation between different genotypes and that there are many model organisms. know their genome. C. elegans has most of the major differentiated tissue types, including: nerve, muscle, hypodermis, intestine, and gonad. C. elegans is also good to use because it can be stored in liquid nitrogen and is still viable. elegans has two genders, hermaphroditic and male. The hermaphrodite has two X chromosomes. It is self-fertilizing, meaning it can produce offspring without needing another C. elegans. This is supported by Current Topics in Developmental Biology when describing genotype (Ross Wolff & Zarkower, 2008). When C. elegans hermaphrodites are young, they produce and store sperm. When the C. elegans is older, it produces eggs. According to the Merriam-Webster dictionary site, an oocyte is an egg before it has matured (Merriam-Webster). The eggs are fertilized by sperm and undergo part of their development inside the hermaphrodite parent.C. elegans are rarely produced in a hermaphrodite population by meiotic nondisjunction at a frequency of 0.1%. According to the Genetics Home Reference, nondisjunction occurs when chromosomes or chromatids do not separate properly. (Home Reference on Genetics). Males only have one X chromosome. This is supported in the Developmental Biology Journal when it states that hermaphrodites are XX and males are XO (Morgan, Critte...... middle of article ......www.genetics.org/ Web. February 28, 2014. .Morgan, Dyan E., Sarah L. Crittenden and Judith Kimble. “The adult male germline of C. Elegans: stem cells and biology. Development 346.2 (2010): 204-14. Web. "Nondisjunction." . “Somatic sexual differentiation in Caenorhabditis Elegans” Current Topics in Developmental Biology 83 (2008): February 1-39... 2014. .