Archer Margaret A, Bradley Timothy J, Mueller Laurence D, Rose Michael R
Department of Ecology and Evolutionary Biology, University of California, Irvine, California 92617, USA.
Physiol Biochem Zool. 2007 Jul-Aug;80(4):386-98. doi: 10.1086/518354. Epub 2007 May 8.
Data from populations undergoing experimental evolution can be used to make comparisons between physiologically differentiated populations and to determine evolutionary trajectories. Comparisons of long-established laboratory populations of Drosophila melanogaster that are strongly differentiated with respect to desiccation resistance are used to test alternative hypotheses concerning the mechanisms that fruit flies use to survive bouts of extreme desiccation. This comparative study supports the hypothesis that, in at least one case, D. melanogaster can evolve increased resistance to desiccation by decreasing water loss rates and by increasing bulk water content but not by increasing metabolic water content or dehydration tolerance. While glycogen was involved in water storage, its primary role was in water binding, not the production of metabolic water. Measurement of the trajectories of these component mechanisms during selection for desiccation resistance is used to demonstrate that water loss rate quickly plateaus in response to selection, while water content continues to improve. This disparity reveals the value of studying evolutionary trajectories and the need for longer-term selection studies in evolutionary physiology.
来自经历实验性进化的种群的数据可用于比较生理分化的种群，并确定进化轨迹。对长期建立的黑腹果蝇实验室种群进行比较，这些种群在抗干燥能力方面有很大差异，用于检验关于果蝇在极端干燥情况下生存机制的替代假设。这项比较研究支持了这样一种假设，即在至少一种情况下，黑腹果蝇可以通过降低失水率和增加总含水量来进化出更高的抗干燥能力，而不是通过增加代谢水含量或脱水耐受性。虽然糖原参与了水分储存，但其主要作用是结合水，而不是产生代谢水。在选择抗干燥能力的过程中测量这些组成机制的轨迹，以证明失水率在选择后迅速趋于平稳，而含水量则持续改善。这种差异揭示了研究进化轨迹的价值以及进化生理学中进行长期选择研究的必要性。
