Organisms and identities : the essentiality of genetic constitution at origin

The expanding scope of modem genetic theories and technologies have fueled controversies regarding the reducibility of organisms to their genetic properties. This work considers the defensibility of the view that an organism's identity is determined by the identity of its genetic constitution at origin, in an effort to add to the theoretical framework in which these controversies may be understood. I begin the study of identity conditions for individual organisms by considering Saul Kripke's view that a given human organism (i.e., the Queen) necessarily originates from the actual parents who contribute her particular sperm and egg of origin. This view is contrasted with Elliot and Gallois' assertion that identity of the material constitution of an organism's zygote of origin is sufficient to preserve its identity. I argue against Kripke's same-parents criterion in favor of a view that genetic constitution of origin, involving both configurative (genotypic) and material (genomic) specifications, is necessary and sufficient to identify the organism as a unique and enduring instance of a natural kind through changes and possible worlds. In the genetic constitution of origin is a unifying and fluid structural continuity that is passed along from the zygote to cellular progeny as the organism develops, and that establishes the range of appropriate changes that the organism may endure in the various environments that are compatible with its persistent life. Other conditions that must be satisfied in order for the organism to exist, including its non-genetic conditions of its origin, may be counterfactually altered without loss of the organism's identity. The influence of genetic properties upon an organism's identity has practical relevance for evaluating the genetic engineering of life, gametic and somatic cell genetic therapies, and the desire to have biologically related children. The view offered here may also direct us toward a better understanding of the ethical dimensions of genetic relationships. Finally, this work illuminates the explanatory uniqueness of all levels of material and experiential influence throughout an organism's development.