青藏高原多年冻土沉积物中埋藏植物DNA特征的初步分析

多年冻土沉积物长期处于负温及封闭条件下,使得其中埋藏植物材料得到较好的保存,成为获取古DNA分子的理想材料.采用常规的CTAB法提取多年冻土中埋藏植物材料的DNA,并用琼脂糖凝胶凝胶电泳检测.结果表明,从多年冻土埋藏植物材料中可以提出DNA,而且所提出的DNA不仅具有降解的小分子量DNA分子,而且还有大分子量DNA.提取的埋藏植物材料的DNA多呈棕褐色,指示了在埋藏过程可能发生一定的聚合.电泳结果表明,随埋藏时间的增加(深度增加),埋藏植物材料中DNA含量呈下降趋势.由于埋藏植物材料在不同时代的多年冻土中均有发现,其DNA分子的提取为深入研究其特征所带遗传信息,重现植物大分子物质在地质历史中的演化提供了可能。

DNA Extracted from the Plant Materials Buried in Perennial Frozen Sediments

The plant materials buried in perennial frozen sediments are preserved in a good state due to sub-freezing temperature and insulation. They may be suitable for retrieving ancient DNA. ;In this work, a routine CTAB method has been used to extract DNA from the plant materials buried in perennial frozen sediments of the Qingshui River and Ngoring Lake, Tibetan Plateau. Agarose gel electrophoresis has used to detect the extraction. The result shows that the DNA can be extracted from buried plant materials, which not only contain degraded DNA with low molecular weight, but also consist of the DNA with high molecular weight that has obvious band. In most cases, the extracted DNA has fuscous color from maple to brown that may result from chemical reaction, for example, the product of Millard reaction or aggregation. The DNA concentration in plant sample decreases with the buried depth or time.;Some factors are determined the preservation of ancient DNA in plant materials. First, low temperature obviously slows down the decomposition of DNA. Secondly, lack of liquid water due to soil frozen reduces the hydrolysis of DNA. Thirdly, the insulation due to soil refrozen prevents from oxygen and provides a reductive condition, helpful to the preservation of DNA.;This work shows that the DNA in the plant materials buried in perennial frozen sediment can well be preserved and will be the best materials to trace the DNA genetic information in a long time scale.