Gene expression profile in the pectoralis muscle of penguin juveniles artificially acclimated to marine life

In the present study, we were interested in gene expression changes in the pectoralis muscle of juvenile king penguins during the transition from terrestrial to marine life. Strictly terrestrial during their first year after hatching, king penguin chicks must then depart to sea to reach nutritional emancipation and pectoralis muscle is largely involved in penguin adaptation to the marine environment. To compare these transcriptomic profiles, we realized heterologous hybridization on Affymetrix GeneChip Chicken Genome Arrays, as the chicken is the closest model species for which microarrays are available. The development of a new algorithm, MaxRS, allow us to determine differentially expressed genes implicated in energetic metabolism or involved in cellular defense against reactive oxygen species and associated injuries. Data from NI and SA penguin juveniles are already on GEO n°GSE17725 We compared muscle sample biopsy from 4 penguin juveniles captured just before they undergone their first immersion to cold water (named NI for Never Immersed), 3 penguin juveniles that had completly accomplished their acclimation to marine life (named SA for Sea Acclimated) and 3 penguin juveniles experimentally immersed in cold water (named AA for Artificially Acclimated). AA penguins are NI penguins that moulted in captivity and then are subjected to experimental immersions in cold water (8°C) to simulate acclimatization to marine life. The protocol consisted in a ten successive immersions (5 hours every 2 days) in a water tank (1.2m width, 2.0m long, 1.0m deep).