School of Biological Sciences, University of Northern Colorado, 501 20th Street, Greeley, Colorado, 80639, USA.
Committee on Evolutionary Biology, University of Chicago, 1025 E. 57th Street, Chicago, Illinois, 60637, USA.
Am J Bot. 2019 Mar;106(3):477-488. doi: 10.1002/ajb2.1259. Epub 2019 Mar 22.
Climate cycles of the Quaternary have impacted plants at a global scale, leaving behind a complex genetic legacy. Species of the northern Rocky Mountains of North America were exposed to more uniform glacial patterns than the central and southern ranges, where synergistic relationships between temperature and precipitation caused differences in the timing and extent of glacier onset. We examined the genetic impacts of climate oscillations on Calochortus gunnisonii (Liliaceae) in the central and southern Rocky Mountains.
Populations were sampled from disjunct mountain ranges across the basins of Wyoming and northern and central Colorado. Allelic data from nuclear microsatellites and plastid sequences (trnV-ndhC, petA-psbJ, and rpl16) were used to examine patterns of genetic structure between and among populations along the southern Rocky Mountain corridor.
We infer considerable population structure concordant with mountain range of origin. Clustering analysis supports separate north and south genetic clusters on either side of major basins in Wyoming, suggesting that populations were maintained in two distinct refugia. Additionally, populations within the Sierra Madre Range of southern Wyoming show localized, divergent genetic signal indicative of a third potential glacial refugium. By contrast, recent genetic admixture is observed in the Laramie, Medicine Bow, and Front ranges, where population expansion from glacial refugia has likely occurred.
We conclude that during climate cycles of the Quaternary, C. gunnisonii experienced periods of population expansion and reduction, habitat fragmentation, isolation in three or more refugia, and admixture mirroring genetic impacts of other southern Rocky Mountains organisms.
第四纪的气候循环对全球范围内的植物产生了影响，留下了复杂的遗传遗产。北美的落基山脉北部的物种比中部和南部的山脉更容易受到冰川模式的影响，因为温度和降水之间的协同关系导致了冰川开始时间和范围的差异。我们研究了气候波动对落矶山中部和南部的 Calochortus gunnisonii（百合科）的遗传影响。
从怀俄明州和科罗拉多州北部和中部的不同山脉盆地中采集了种群样本。来自核微卫星和质体序列（trnV-ndhC、petA-psbJ 和 rpl16）的等位基因数据用于研究南部落矶山脉走廊沿线种群之间和种群内部的遗传结构模式。
我们推断出与山脉起源相一致的相当大的种群结构。聚类分析支持在怀俄明州主要盆地两侧的南北遗传聚类，表明种群在两个不同的避难所中得以维持。此外，怀俄明州 Sierra Madre 山脉南部的种群显示出局部的、发散的遗传信号，表明存在第三个潜在的冰川避难所。相比之下，在拉勒米、医学弓和 Front 山脉中观察到了近期的遗传混合，这表明种群可能从冰川避难所中扩张而来。
我们得出结论，在第四纪的气候循环中，C. gunnisonii 经历了种群扩张和减少、栖息地破碎化、三个或更多避难所的隔离以及与其他落矶山南部生物的遗传影响相匹配的混合。
