Biomacromolecules in lake sediments are very important in the indication of environmental information. DNA(Deoxyribonucleic acid) is an important biomacromolecule, and its genetic information which corresponds to organism to indicate information of biology and environmental change of lake sediments con be studied. In recent years, several approaches based on the extraction of DNA from environmental samples have been developed for the microbial diversity in soil and sea sediments.
On the basis of previous work, an efficient method to extract DNA from lake sediments is reported. Samples from location in Lake Taihu were collected, and their genomic DNA with the size of 23kb was obtained from all sediment samples of Meiliang bay. Purification and efficiency of extracted DNA were evaluated through ultraviolet spectrum OD260/ OD280 and OD260/ OD230 ratios. Experimental results show that all samples mentioned above obtain quite purified genomic DNA with OD260/ OD280 ratios from 1.41 to 1.72, and OD260/ OD280 ratios from 1.13 to1.54. The changed regulation of DNA in different sediment depth is elucidated, the distribution of organic carbon and DNA is consistent in 15cm surface sediments, and DNA keeps low contents below 15cm. The extracted DNA is sufficient enough to be served as a template for PCR amplification of specific genetic sequences. In particular, Microcystis 16S rRNA gene fragments (200bp gene fragments) were obtained from 5 samples.