Data from: The adaptive cline at Ldh (lactate dehydrogenase) in killifish Fundulus heteroclitus remains stationary after 40 years of warming estuaries

Since the 1970s, water temperatures along the Atlantic seaboard of the United States have risen by an average of 0.5ºC in summer months and 2.2ºC in winter months. In response, the distribution and abundance of several nearshore species have changed dramatically, but no study has attempted to document whether estuarine populations have evolved greater thermal tolerance. Here, we re-examine the classic latitudinal cline at lactate dehydrogenase in the killifish Fundulus heteroclitus that was originally described by Dennis Powers and associates from samples collected between 1970-72. Laboratory and field evidence indicated that northern and southern isozymes at muscle lactate dehydrogenase (LDH) are locally adapted to cold and warm temperatures, respectively. Despite the potential for evolutionary response at this adaptive locus, we detected no significant shift of the LDH cline between the early 1970s and 2010. We conclude that microevolution of LDH-mediated thermal tolerance has not occurred, shifts in alleles are too incremental to be distinguished from random processes, or that F. heteroclitus uses phenotypic and genetic mechanisms besides LDH to respond to warmer waters.自20世纪70年代以来，美国大西洋沿岸海域夏季水温平均上升0.5℃，冬季平均上升2.2℃。受此环境变化影响，多种近岸物种的分布与种群丰度发生了显著改变，但目前尚无研究旨在探明河口种群是否演化出了更强的热耐受性（thermal tolerance）。本研究重新考察了由丹尼斯·鲍尔斯（Dennis Powers）及其团队于1970至1972年间基于采集样本首次描述的斑节底鳉（Fundulus heteroclitus）肌肉乳酸脱氢酶（lactate dehydrogenase, LDH）的经典纬度渐变群。实验室与野外证据均表明，该物种肌肉LDH的北方与南方同工酶分别适应寒冷与温暖的水温环境。尽管该适应性位点存在演化响应的潜力，但我们并未检测到1970年代早期至2010年间LDH渐变群发生显著偏移。据此我们得出结论：要么未发生LDH介导的热耐受性微演化，要么等位基因频率的变化过于渐进，无法与随机过程区分开来，亦或是斑节底鳉采用了除LDH之外的表型与遗传机制以应对水温升高。