A comparison between egg trancriptomes of cod and salmon reveals species-specific traits in eggs for each species

• Published in: Molecular Reproduction and Development
• Main Authors: Wargelius, Anna, Furmanek, Tomasz, Montfort, Jérôme, Le Cam, Aurélie, Kleppe, Lene, Juanchich, Amélie, Edvardsen, Rolf B., Taranger, Geir Lasse, Bobe, Julien
• Other Authors: Institute of Marine Research, Laboratoire de Physiologie et Génomique des Poissons (LPGP), Structure Fédérative de Recherche en Biologie et Santé de Rennes ( Biosit : Biologie - Santé - Innovation Technologique )-Institut National de la Recherche Agronomique (INRA), European Project: 222719,EC:FP7:KBBE,FP7-KBBE-2007-2A,LIFECYCLE(2009)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2015
• Subjects: [SDV]Life Sciences [q-bio]; atlantic cod; Atlantic salmon
• Online Access: https://hal.archives-ouvertes.fr/hal-01205122; https://doi.org/10.1002/mrd.22487

Fish in use in aquaculture display large variation in gamete biology. To reach better understanding around this issue, this study aims at identifying if species specific "egg life history traits" can be hidden in the unfertilized egg. This was done by investigating egg transcriptome differences between Atlantic salmon and Atlantic cod. Salmon and cod eggs were selected due to their largely differencing phenotypes. An oligo microarray analysis was performed on ovulated eggs from cod (n = 8) and salmon (n = 7). The arrays were normalized to a similar spectrum for both arrays. Both arrays were re-annotated with SWISS-Prot and KEGG genes to retrieve an official gene symbol and an orthologous KEGG annotation, in salmon and cod arrays this represented 14,009 and 7,437 genes respectively. The probe linked to the highest gene expression for that particular KEGG annotation was used to compare expression between species. Differential expression was calculated for genes that had an annotation with score >300, resulting in a total of 2,457 KEGG annotations (genes) being differently expressed between the species (FD > 2). This analysis revealed that immune, signal transduction and excretory related pathways were overrepresented in salmon compared to cod. The most overrepresented pathways in cod were related to regulation of genetic information processing and metabolism. To conclude this analysis clearly point at some distinct transcriptome repertoires for cod and salmon and that these differences may explain some of the species-specific biological features for salmon and cod eggs. Mol. Reprod. Dev. 2015. © 2015 Wiley Periodicals, Inc.