Mitton Jeffry B, Duran Kristy L
Department of Ecology and Evolutionary Biology, Campus Box 334, University of Colorado, Boulder, CO 80309, USA.
Mol Ecol. 2004 May;13(5):1259-64. doi: 10.1111/j.1365-294X.2004.02122.x.
Three previous reports of microgeographical variation of glycerate dehydrogenase (Gly) frequencies in piñon, Pinus edulis, established the hypothesis that Gly frequencies contribute to adaptation to heterogeneous environments, specifically to variation in soil moisture. In each of these studies, the frequency of the Gly-3 allele or of Gly-33 homozygotes was higher on dry sites than on nearby moist sites. Here we attempt to extend these observations by testing the hypothesis that Gly frequencies respond to soil moisture variation on a range-wide scale. Gly frequencies were surveyed in 11 natural populations, and the frequency of the Gly-3 allele varied from 0.27 to 0.65 among the sample sites. Elevation varied from 1650 to 3100 m, and summer precipitation, defined as precipitation from April to August, varied from 13.7 to 26.4 cm. The soil types at the collection sites were schist, quaternary volcanic or a mixture of shale and sandstone. Logistic regression revealed that Gly frequencies did not respond to either elevation or soil type, but were related to summer precipitation (P < 0.01). The correlation between summer precipitation and the frequency of the Gly-3 allele was r = -0.92 (P < 0.001). Thus, the patterns of differentiation on microgeographical scales are consistent with greater differentiation on a range-wide scale.
之前有三篇关于矮松（Pinus edulis）甘油酸脱氢酶（Gly）频率微观地理变异的报告，提出了这样一个假说：Gly频率有助于适应异质环境，特别是土壤湿度的变化。在每一项此类研究中，Gly-3等位基因或Gly-33纯合子在干燥地点的频率高于附近的湿润地点。在此，我们试图通过检验Gly频率在全范围尺度上对土壤湿度变化作出响应这一假说，来扩展这些观察结果。我们对11个自然种群的Gly频率进行了调查，样本地点中Gly-3等位基因的频率在0.27至0.65之间变化。海拔高度在1650至3100米之间变化，夏季降水量（定义为4月至8月的降水量）在13.7至26.4厘米之间变化。采集地点的土壤类型为片岩、第四纪火山岩或页岩与砂岩的混合物。逻辑回归分析表明，Gly频率对海拔或土壤类型均无响应，但与夏季降水量有关（P < 0.01）。夏季降水量与Gly-3等位基因频率之间的相关性为r = -0.92（P < 0.001）。因此，微观地理尺度上的分化模式与全范围尺度上更大的分化是一致的。
