Meeting Abstract
A key adaptation of mammals to their environment is their ability to maintain a constant high body temperature, even at rest, under a wide range of conditions (i.e. endothermy). In cold climates, this is achieved by an adaptive production of endogenous heat, known as nonshivering thermogenesis (NST), in the brown adipose tissue (BAT). This organ, unique to mammals, contains a very high density of mitochondria, and thus the correct functioning of the BAT ultimately relies on the correct functioning of its mitochondria. Remarkably, because mitochondria enclose proteins encoded both in the maternally inherited mitochondrial genome and in the biparentally inherited nuclear genome, one hypothesis is that both genomes and their interaction may shape mammalian NST and other phenotypic traits such as body mass. By housing under similar standardised conditions wild-derived common voles from two distinct mitochondrial lineages (Western and Central), we show that Western voles have greater NST capacity and were heavier than Central voles. By introgressing these two lineages over more than 10 generations, we then experimentally tested the contribution of the nuclear and mitochondrial genomes. This shows that BAT weight and NST capacity were significantly influenced by the nuclear and mitochondrial genomes, respectively, and that whole animal body weight was influenced by mito-nuclear interaction. These findings turn new light on the importance of the mitochondrial and nuclear genomes in shaping the phenotype and building adaptation to the environment in mammals.
