Extracting DNA from faecal sample is a newly developed technology of recent years. Although several methods to extract DNA from faeces have been developed home and abroad, they addressed fresh samples and it is still blank in extracting DNA from old faeces yet. Extracting old faeces’ DNA can make the full use of transfers out or the death animal’s genetic information and expanding the application scope of Molecular Scatology. In this experiment two groups of faeces were launched into DNA extracting. One group had been preserved by absolute ethanol for 3 years and the other group had been preserved by absolute ethanol for half past 4 years. Aiming at the old faecal’s characteristic of small number of cells and high degrading of DNA, several repetitions(4 tubes) were carried out at the same time in this experiment. Then 4 different DNA extracting methods (Preprocess-phenol/chloroform extraction method, Guanidine thiocyanate method, CTAB method, QIAamp DNA Stool Mini Kit, Qiagen) were followed. From these parallel methods and their corresponding results, we could get the best method while the possibility of extracting DNA from old faecal was studied. After DNA was dissolved in TE we got the original DNA. Finally we collected the original DNA from the 4 repetitions then purified and concentrated it by using DNA purification kit. In the end, the results of PCR amplification shows that only Preprocess-phenol/chloroform extraction method can extract enough DNA for PCR from two groups of faeces. In our study, we extracted DNA from old faeces successfully and got some genetic information from mtDNA. This result confirms the possibility of putting old faecal into molecular scatology study.
以粪便为材料提取动物DNA进行动物保护遗传学和分子生态学研究的关键是能否提取到高质量的粪便DNA。然而提取方法通用性不好和产物质量不高等问题阻碍了粪便DNA分析技术的推广。本文介绍的改进型十六烷基三甲基溴化铵提取法可广泛适用于各食性哺乳动物粪便DNA提取,在11种不同食性动物的粪便DNA提取实验中验证了它的可靠性和通用性。本方法成本低廉(3元/样),用实验室常规试剂即可完成粪便DNA提取,其产物纯度高于专用试剂盒QIAamp DNA Stool Kit,在拥有超过专业试剂盒提取效果的同时尽可能的降低了实验成本,有利于粪便DNA技术的推广。
