Parasitism Genes: What They Reveal about Parasitism

Nematodes are parasites of plants and animals that have evolved diverse and often specific mechanisms to promote a given parasitic lifestyle (Baldwin et al. 2004; Jasmer et al. 2003), including modifications of developmental and reproductive potential, dissemination amongst and location of primary or alternate hosts, and survival strategies in the absence of a suitable host or favorable environment. The genetic pathways underlying these lifecycle adaptations may have parallels with or origins in nonparasitic nematode species that must also adapt to a dynamic or unstable niche. Distinct to the parasites, however, are adaptations to obtain organic nutriment while living in or on another organism. The products of such parasitism genes “may be manifested as morphological structures that provide access to parasitism of a particular host (e.g. a nematode stylet) or they may play critical physiological roles in the interaction of the nematode with its host” (Davis et al. 2000).