Data from: Environmental and genetic influences on body mass and resting metabolic rates (RMR) in a natural population of weasel Mustela nivalis

Body mass (BM) and resting metabolic rates (RMR) are two inexorably linked traits strongly related to mammalian life histories. Yet, there have been no studies attempting to estimate heritable variation and covariation of BM and RMR in natural populations. We used a marker-based approach to construct a pedigree and then the ‘animal model’ to estimate narrow sense heritability (h^2) of these traits in a free-living population of weasels Mustela nivalis – a small carnivore characterised by a wide range of BM and extremely high RMR. The most important factors affecting BM of weasels were sex and habitat type, whereas RMR was significantly affected only by seasonal variation of this trait. All environmental factors had only small effect on estimates of additive genetic variance of both BM and RMR. The amount of additive genetic variance associated with BM and estimates of heritability were high and significant in males (h^2 = 0.61), but low and not significant in females (h^2 = 0.32), probably due to small sample size for the latter sex. The results from the two-trait model revealed significant phenotypic (r_P = 0.62) and genetic correlation (r_A = 0.89) between BM and whole body RMR. The estimate of heritability of whole body RMR (0.54) and body mass corrected RMR (0.45) were lower than estimates of heritability for BM. Both phenotypic and genetic correlations between body mass corrected RMR and BM had negative signals (r_P = -0.42 and r_A = -0.58). Our results indicate that total energy expenditures of individuals can quickly evolve through concerted changes in BM and RMR.

体重（Body mass, BM）与静息代谢率（Resting Metabolic Rates, RMR）是两类紧密关联的性状，与哺乳动物生活史密切相关。然而，目前尚无研究尝试估算野生种群中BM与RMR的遗传变异及遗传协变关系。本研究采用基于标记的方法（marker-based approach）构建谱系，并借助动物模型（animal model）估算了野生伶鼬（Mustela nivalis）种群这两类性状的狭义遗传力（narrow sense heritability, h²）。伶鼬是一类体型跨度广、静息代谢率极高的小型食肉动物。影响伶鼬体重的核心因素为性别与生境类型，而静息代谢率仅受该性状的季节变化显著影响。所有环境因素对两类性状的加性遗传方差（additive genetic variance）估算仅产生微弱作用。雄性个体中，与体重相关的加性遗传方差及遗传力估算值较高且显著（h²=0.61），而雌性个体中该值较低且不显著（h²=0.32），这可能缘于雌性样本量较小。双性状模型（two-trait model）的分析结果显示，体重与整体静息代谢率间存在显著的表型相关（phenotypic correlation, r_P=0.62）与遗传相关（genetic correlation, r_A=0.89）。整体静息代谢率的遗传力估算值（0.54）及体重校正后的静息代谢率（body mass corrected RMR）的遗传力估算值（0.45）均低于体重的遗传力估算值。体重校正后的静息代谢率与体重间的表型相关与遗传相关均呈负值（r_P=-0.42，r_A=-0.58）。本研究结果表明，个体的总能量消耗可通过体重与静息代谢率的协同变化快速演化。