Department of Ecology and Genetics, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden.
Science. 2012 Mar 2;335(6072):1083-6. doi: 10.1126/science.1216043.
It is commonly believed that trees were absent in Scandinavia during the last glaciation and first recolonized the Scandinavian Peninsula with the retreat of its ice sheet some 9000 years ago. Here, we show the presence of a rare mitochondrial DNA haplotype of spruce that appears unique to Scandinavia and with its highest frequency to the west-an area believed to sustain ice-free refugia during most of the last ice age. We further show the survival of DNA from this haplotype in lake sediments and pollen of Trøndelag in central Norway dating back ~10,300 years and chloroplast DNA of pine and spruce in lake sediments adjacent to the ice-free Andøya refugium in northwestern Norway as early as ~22,000 and 17,700 years ago, respectively. Our findings imply that conifer trees survived in ice-free refugia of Scandinavia during the last glaciation, challenging current views on survival and spread of trees as a response to climate changes.
人们普遍认为，在上一个冰河时期，斯堪的纳维亚半岛上没有树木，大约 9000 年前，随着冰盖的退缩，树木才首次重新出现在斯堪的纳维亚半岛。在这里，我们展示了一种罕见的云杉线粒体 DNA 单倍型的存在，这种单倍型似乎是斯堪的纳维亚半岛所独有的，而且在西部的频率最高——据信，在过去的大部分冰期，该地区都有冰期避难所。我们进一步表明，在挪威中部特隆德拉格的湖泊沉积物和花粉中，可以追溯到约 10300 年前，以及在西北无冰的安多亚避难所附近的湖泊沉积物中的松属和云杉属的叶绿体 DNA 中，都存在这种单倍型的 DNA。我们的发现表明，在上一个冰河时期，针叶树在斯堪的纳维亚的无冰避难所中幸存下来，这对当前关于树木作为应对气候变化而幸存和传播的观点提出了挑战。
