Biology of teleost primordial germ cells (PGCs) and spermatogonia: Biotechnological applications Vanesa Robles a,b, ⁎, Marta F. Riesco c , Martin Psenicka d , Taiju Saito d,e , David G. Valcarce b,f , Elsa Cabrita c , Paz Herráez b,f a IEO, Spanish Oceanographic Institute, Santander Oceanographic Centre, Promontorio de San Martín s/n, P.O. Box 240, 39080 Santander, Spain b INDEGSAL, University of León, 24071 León, Spain c CCMAR, Center for Marine Sciences, University of Algarve, Campus Gambelas, 8005-139 Faro, Portugal d Research Institute of Fish Culture and Hydrobiology, South Bohemian Research Center of Aquaculture and Biodiversity of Hydrocenoses, Faculty of Fisheries and Protection of Waters, University of South Bohemia in Ceske Budejovice, Vodňany, Czech Republic e Nishiura Station, South Ehime Fisheries Research Center, Ehime University, Uchidomari, Ainan, Ehime 798-4206, Japan f Department of Molecular Biology, Area of Cell Biology, University of León, 24071 León, Spain abstract article info Article history: Received 3 June 2015 Received in revised form 16 February 2016 Accepted 3 March 2016 Available online xxxx This review provides a general view on teleost germline development using primordial germ cells (PGCs) or spermatogonia (SG), highlighting recent progress in research on these two cell types in teleost fishes. Due to the interest of these cells for gene banking purposes, this chapter also reviews the available protocols for cryopreservation and the techniques that have been employed to assess cellular and molecular status after the process. Protocols for in vitro culture and the possibility of generating PGCs in vitro from non-committed embry- onic cells are also discussed. Furthermore, the potential of these cells in surrogate production is presented, analyzing the transplantation and xenotransplantation experiments performed in fish. © 2016 Elsevier B.V. All rights reserved. Keywords: Germline Cryopreservation Cell culture Surrogate production Xenotransplantation 1. Introduction Teleost primordial germ cells, as the embryonic precursors of gam- etes, have tremendous importance in the fields of developmental biolo- gy and aquaculture. From a basic science point of view, they offer, an ideal model to study cell migration mechanisms; from an applied sci- ence perspective relative to endangered species and high value culture species, they are an optimal cell type to be cryopreserved because they conserve both paternal and maternal genomes. Moreover, recent studies have demonstrated the competence and suitability of these cells for surrogate production. The implementation of these technolo- gies provides precise control over many relevant reproductive aspects. For example, PGC or SG xenotransplantation could offer a solution for the management of species with reproductive failures, or for those spe- cies with long maturation periods. Model species have been relevant to develop basic knowledge and to make all of these applications accessi- ble for commercially valuable species. As an example, zebrafish, has been essential for the discovery of important molecular aspects of teleost germline development, including specific germ cell molecular markers that have been crucial for the study of cell specification and migration. These markers allow the identification of PGCs and SGs, either to study their distribution in the genital ridge and gonad, their proliferation in vitro, or their migration after transplantation into a host. The goal of this review is to provide a general picture of the scientific progress in germ cell studies, focusing on those achievements with spe- cial relevance for Aquaculture. 2. Germline development in male teleost fish In fish, PGCs migrate during embryonic development from where they are formed toward the genital ridge. PGC migration is well studied in model fish species, such as zebrafish and medaka; primordial germ cell specification and development for these species have been thor- oughly discussed (Raz 2004; Herpin et al., 2007; Dosch, 2015). Howev- er, the migratory pattern in fishes varies among species, in part because of variety of egg size, shape, and developmental specificities. For ad- vanced PGC biotechnological applications, such as transplantation of PGCs for surrogate production, it is necessary to understand the differ- ence of PGC development among fishes. In this section, the main focus will be to describe the PGC distinctive features, the different techniques Aquaculture xxx (2016) xxx–xxx ⁎ Corresponding author at: IEO, Spanish Oceanographic Institute, Santander Oceanographic Centre, Promontorio de San Martín s/n, P.O. Box 240, 39080 Santander, Spain. E-mail address: robles.vanesa@gmail.com (V. Robles). AQUA-632041; No of Pages 17 http://dx.doi.org/10.1016/j.aquaculture.2016.03.004 0044-8486/© 2016 Elsevier B.V. All rights reserved. Contents lists available at ScienceDirect Aquaculture journal homepage: www.elsevier.com/locate/aquaculture Please cite this article as: Robles, V., et al., Biology of teleost primordial germ cells (PGCs) and spermatogonia: Biotechnological applications, Aquaculture (2016), http://dx.doi.org/10.1016/j.aquaculture.2016.03.004