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 occ...

自20世纪70年代以来，美国大西洋沿岸海域夏季水温平均升高0.5℃，冬季平均升高2.2℃。受此影响，多种近岸物种的分布与种群丰度均发生了显著变化，但目前尚无研究旨在记录河口种群是否已演化出更强的耐热性。本研究重新检视了由丹尼斯·鲍尔斯（Dennis Powers）及其合作者于1970至1972年采集的样本中，最初被报道的底鳉（*Fundulus heteroclitus*）乳酸脱氢酶（lactate dehydrogenase, LDH）经典纬度梯度格局。实验室与野外证据表明，该物种肌肉乳酸脱氢酶的南北同工酶分别适应当地的寒冷与温暖生境。尽管该适应性位点存在演化响应的潜在可能，但我们并未检测出1970年代早期至2010年间LDH梯度的显著偏移。我们得出结论，由LDH介导的耐热性相关的微演化尚未发生……