Testes and brain gene expression in precocious male and adult maturing Atlantic salmon (Salmo salar)

• Published in: BMC Genomics
• Main Authors: Guiry, A, Flynn, D, Hubert, S, O'Keeffe, A, LeProvost, O, White, S L, Forde, P F, Davoren, P, Houeix, B, Smith, T J, Cotter, D, Wilkins, N P, Cairns, M T
• Format: Article in Journal/Newspaper
• Language: English
• Published: Biomed Central 2010
• Subjects: Testes; brain gene; male; maturing; Atlantic salmon; Salmo salar
• Online Access: http://hdl.handle.net/10793/425; https://doi.org/10.1186/1471-2164-11-211

The electronic version of this article is the complete one and can be found online at: http://www.biomedcentral.com/1471-2164/11/211 peer-reviewed Background: The male Atlantic salmon generally matures in fresh water upon returning after one or several years at sea. Some fast-growing male parr develop an alternative life strategy where they sexually mature before migrating to the oceans. These so called ‘precocious’ parr or ‘sneakers’ can successfully fertilise adult female eggs and so perpetuate their line. We have used a custom-built cDNA microarray to investigate gene expression changes occurring in the salmon gonad and brain associated with precocious maturation. The microarray has been populated with genes selected specifically for involvement in sexual maturation (precocious and adult) and in the parr-smolt transformation. Results: Immature and mature parr collected from a hatchery-reared stock in January were significantly different in weight, length and condition factor. Changes in brain expression were small - never more than 2-fold on the microarray, and down-regulation of genes was much more pronounced than up-regulation. Significantly changing genes included isotocin, vasotocin, cathepsin D, anamorsin and apolipoprotein E. Much greater changes in expression were seen in the testes. Among those genes in the testis with the most significant changes in expression were anti-Mullerian hormone, collagen 1A, and zinc finger protein (Zic1), which were down-regulated inprecocity and apolipoproteins E and C-1, lipoprotein lipase and anti-leukoproteinase precursor which were upregulated in precocity. Expression changes of several genes were confirmed in individual fish by quantitative PCR and several genes (anti-Mullerian hormone, collagen 1A, beta-globin and guanine nucleotide binding protein (G protein) beta polypeptide 2-like 1 (GNB2L1) were also examined in adult maturing testes. Down-regulation of anti-Mullerian hormone was judged to be greater than 160-fold for precocious males and greater than ...