James O. Fredrickson

Traditionally, the genes which contribute to the phenotype of a eukaryotic organism were considered to be housed within its nuclear genome, but today this is often understood to not be the case. In order to better understand how high-level complex phenotypic expressions arise I propose a conceptual framework composed of core systems biology ideas integrated with current understanding of genetic systems: gene systems hypothesis (GSH). The implications of this GSH framework allow for an organism level functional gene system (O-FGS) definition which incorporates the integration of macro- and micro-symbiont gene systems. In support of the proposed O-FGS definition a brief review of current literature is presented which demonstrates the influence of micro- and macro-symbionts in plant and animal development, growth and persistence.