Bacigalupe Leonardo D, Nespolo Roberto F, Opazo Juan C, Bozinovic Francisco
Centro de Estudios Avanzados en Ecología y Biodiversidad, Departamento de Ecología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, 6513677, Chile.
Physiol Biochem Zool. 2004 Sep-Oct;77(5):805-15. doi: 10.1086/422229.
The goal of our work was to understand the role of a novel thermal environment in shaping the phenotypic expression of thermogenic capacity and organ size. To examine this we compared two populations of the South American rodent Phyllotis darwini from different altitudes (Andean and valley populations), taking advantage of the fact that this genus originated at high altitude in the Andean plateau. DNA mitochondrial analysis showed that the two populations were separated and then experienced different thermal regimens for at least the last 450,000 yr. We expected the two populations of P. darwini to present more metabolic and organ size similarities if phylogenetic inertia had been an important factor. In this sense, phylogenetic inertia means that the valley population would retain evolutionary adaptations of high altitude: a greater phenotypic flexibility in both physiological and morphological traits. In general, our results indicate that the actual thermogenic capacities (magnitude and flexibility) of the valley population are a consequence of phylogenetic inertia. On the other hand, results for organ size (magnitude and flexibility) could suggest that this population would have adapted to the less seasonal central valley.
我们这项工作的目标是了解一种新型热环境在塑造产热能力和器官大小的表型表达中所起的作用。为了对此进行研究，我们比较了来自不同海拔高度（安第斯山脉种群和山谷种群）的南美啮齿动物达尔文叶耳鼠的两个种群，利用了该属起源于安第斯高原高海拔地区这一事实。线粒体DNA分析表明，这两个种群在过去至少45万年里是分离的，并且经历了不同的热环境。如果系统发育惯性是一个重要因素，我们预计达尔文叶耳鼠的这两个种群会表现出更多的代谢和器官大小相似性。从这个意义上说，系统发育惯性意味着山谷种群会保留高海拔地区的进化适应性：在生理和形态特征上具有更大的表型灵活性。总体而言，我们的结果表明，山谷种群实际的产热能力（大小和灵活性）是系统发育惯性的结果。另一方面，器官大小（大小和灵活性）的结果可能表明，这个种群已经适应了季节性较弱的中央山谷。
