Abstracts (first author)
Discovering the genetic basis of torpor in a Chilean marsupial
Torpor is the physiologically controlled reduction of metabolic rate and body temperature experienced by small endotherms when facing periods of low temperature and/or food resources. This phenotype is characterized by an almost complete suppression of all expensive physiological processes with the aim of reducing energy expenditure. Nevertheless, some processes continue to operate at lower levels of activity, as they are critical for survival. The high demand of energy required during rewarming, to reach normothermy, represents an important constraint. Torpor and arousal from torpor involves a complex physiological reorganization at different organizational levels, underpinned by changes in genes expression. Accordingly in this study we investigated the reaction norm of (1) gene expression and (2) mitochondrial performance along different stages of torpor bout (deep torpor, arousal and normothermy) in the Chilean marsupial Thylamys elegans. More specifically we (1) performed a large-scale gene expression screening (RNA-seq) and (2) examined mitochondrial oxygen consumption and different enzymes of the electron transport system associated with torpor in liver. The gene expression profiles revealed a modest level of transcriptional changes along different stages of torpor bout. Functional analysis shows that genes involved in pathways associated to lipid metabolism are increased, whereas those involved in protein biosynthesis and detoxification are decreased during torpor and rewarming. For mitochondrial performance, high level of phenotypic flexibility was observed during the different stages of torpor. Taken together, these findings revealed important metabolic process those are critical during torpor in marsupials.