Dissertation Research: Fine Scale Evolutionary Adaptation to Temperature: A Comparative Approach Using Porcelain Crabs(genus Petrolisthes)

石石属的海瓷蟹分布在广泛的地理范围内——从极热的热带环境到寒冷的北温带和南温带地区——并且在潮间带和潮下带的高度差异很大。因此，岩石类的同系物在平均温度和温度范围上有很大的差异，这使得这些螃蟹成为一个很好的研究系统，可以在一个相对狭窄的分类群体中研究对温度的进化适应。PI对来自低潮间带和高潮间带的两种同系物，P. eriomerus和P. cincpes的初步研究表明，它们普遍适应温度和回归压力。拟议的研究建立在这项工作的基础上，并包括几个额外的同系物：(1)致命温度上限的确定；(2)乳酸脱氢酶结构和动力学性质的温度敏感性检验；(3)测定腿膜结构在气体交换中的作用；(4)利用大亚基核糖体RNA基因序列进行分子系统发育。后一种实验将能够在系统发育背景下分析生理-生化-分子特征的种间差异，从而使假定的“适应性”差异与非由于温度进化反应而产生的变化区分开来。

Somero 9700701 Marine porcelain crabs of the genus Petrolisthes occur over a wide geographical range--from extremely hot tropical environments to cold north- and south temperate regions--and at widely different heights in the intertidal and subtidal zones. Thus, congeners of Petrolisthes encounter substantial differences in mean temperature and temperature range, making these crabs an excellent study system for examining evolutionary adaptation to temperature within a relatively narrow taxonomic group. The PI's initial studies of two congeners, P. eriomerus and P. cinctipes from low- and high intertidal zones, respectively, indicate pervasive adaptations to temperature and emersion stress. The proposed studies build on this work, and include, for several additional congeners: (1) determination of upper lethal temperature limits; (2) examination of the temperature sensitivity of structural and kinetic properties of lactate dehydrogenase; (3) determination of the function of leg membrane structures in gas exchange; and (4) development of a molecular phylogeny, using the sequence of the large subunit ribosomal RNA gene The latter experiments will enable analysis of the interspecific differences in physiological-biochemical-molecular traits to be analyzed in a phylogenetic context, thus enabling putative "adaptive" differences to be distinguished from changes not due to evolutionary responses to temperatures. .