New tools for genome preservation: grafting germinal cells in brown trout ( S almo trutta )

Primordial germ cells (PGCs) are the only cells in developing embryos with the potential to transmit genetic information to the next generation, making them excellent candidates for gene banking and cryopreservation (Saito et al., 2008). PGCs originate from the germ cell line, producing spermatogonia and oogonia, which, in turn, preserve two main functions: self-renewal and production of gametes. The potential of primordial germ cells to resume gametogenesis after intra- or inter-specific grafting has been reported for a limited number of species during the last years (Takeuchi et al., 2004; Yoshizaki et al., 2010). These findings opened great expectations for the development of new biotechnologies in aquaculture, the possibility to generate germ-line quimeras for surrogate production being one of the most suggested option. Recent studies showed that this ability is maintained in more differentiated cells of the germinal line, the spermatogonia (Okutsu et al., 2006; Lacerda et al., 2010; Yazawa et al., 2010), which are easier to obtain from immature testes. The objective of the present study was, therefore, to evaluate the use of these tools in the conservation programmes of brown trout populations from the Northwest of Spain, which are threatened by extinction. In this work we wanted to check the effectiveness of the protocols for testes dissociation and spermatogonia enrichment of this species and evaluate the ability of cells to colonize the host gonads after intra-specific grafting.Research supported by the Spanish Ministry of Science and Innovation, PGCFISH (AGL2008-02172) project.Peer Reviewe