title: Spermatogonial transplantation in fish: A novel method for the preservation of genetic resources.
abstract: Recent progress in genome-based breeding has created various fish strains carrying desirable genetic traits; however, methods for the long-term preservation of their genetic resources have not yet been developed, mainly due to the lack of cryopreservation techniques for fish eggs and embryos. Recently, we established an alternative cryopreservation technique for fish spermatogonia using a slow-freezing method. Furthermore, we developed a transplantation system to produce functional eggs and sperm derived from spermatogonia. Spermatogonia isolated from the testes of vasa-green fluorescent protein (Gfp) transgenic rainbow trout (Oncorhynchus mykiss) were transplanted into the peritoneal cavity of triploid masu salmon (Oncorhynchus masou) hatchlings of both genders. The transplanted trout spermatogonia migrated towards the gonadal anlagen of the recipient salmon, into which they were subsequently incorporated. We confirmed that the donor-derived spermatogonia resumed gametogenesis, and produced sperm and eggs in male and female recipient salmon, respectively. Fertilization of the resultant eggs and sperm produced only rainbow trout in the first filial (F₁) generation, suggesting that the sterile triploid recipient salmon produced functional eggs and sperm derived from the trout donors. A combination of spermatogonial transplantation and cryopreservation could be a powerful tool for preserving valuable fish strains with desirable genetic traits and endangered species.
authors.affiliation: Department of Marine Biosciences, Tokyo University of Marine Science and Technology, Japan. goro@kaiyodai.ac.jp
authors.forename: Goro
authors.initials: G
authors.lastname: Yoshizaki
authors.forename: Kiyoko
authors.initials: K
authors.lastname: Fujinuma
authors.forename: Yoshiko
authors.initials: Y
authors.lastname: Iwasaki
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Okutsu
authors.forename: Shinya
authors.initials: S
authors.lastname: Shikina
authors.forename: Ryosuke
authors.initials: R
authors.lastname: Yazawa
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Takeuchi
mesh_terms: D000818:Animals; D015925:Cryopreservation; D005260:Female; D008297:Male; D017686:Oncorhynchus mykiss; D013093:Spermatogonia / Q000637:transplantation*; D057885:Triploidy