Department of Forensic Medicine, Tongji Medical College, Huazhong University of Science and Technology, No. 13, HangkongRoad, Wuhan 430030, Hubei, P.R. China.
Forensic Judicial Appraisal Center of Beijing Public Security Bureau, No.1, Longgang Beijing Road, Beijing 100192, P.R. China.
FEMS Microbiol Lett. 2020 Sep 1;367(17). doi: 10.1093/femsle/fnaa145.
The presence of diatoms in victim's internal organs has been regarded as a gold biological evidence of drowning. The idea becomes true at the advent of DNA metabarcoding. Unfortunately, the DNA barcode of diatoms are far from being applicable due to neither consensus on the barcode and nor reliable reference library.In this study we tested 23 pairs of primers, including two new primer pairs, Baci18S (V4 of 18S) and BacirbcL (central region of rbcL), for amplifying fragments of 16S/18S, 23S/28S, COI, ITS and rbcL. A total of five pairs of primers performed satisfactory for diatoms. We used three of them, 18S605 (V2 + V3 of 18S), Baci18S and BacirbcL, to barcode four water samples using next generation sequencing platform. The results showed that these primers worked well for NGS metabarcoding of diatoms. We suggest that 18S605, Baci18S and BacirbcL be barcodes of diatoms and the corresponding primer pairs be used. Considering a quite high proportion of sequences deposited in GenBank were mislabeled, the most urgent task for DNA barcoding of diatoms is to create standard sequences using correctly identified specimens, ideally type specimens.
硅藻存在于受害者内脏器官中被认为是溺亡的黄金生物学证据。随着 DNA 代谢组学的出现，这一观点成为了现实。不幸的是，由于没有关于条码的共识，也没有可靠的参考文库，硅藻的 DNA 条码远未得到实际应用。在本研究中，我们测试了 23 对引物，包括两个新的引物对 Baci18S（18S 的 V4）和 BacirbcL（rbcL 的中心区域），用于扩增 16S/18S、23S/28S、COI、ITS 和 rbcL 的片段。共有五对引物对硅藻表现出令人满意的效果。我们使用其中的三对引物，18S605（18S 的 V2+V3）、Baci18S 和 BacirbcL，通过下一代测序平台对四个水样进行了条码标记。结果表明，这些引物非常适合用于硅藻的 NGS 代谢组学研究。我们建议将 18S605、Baci18S 和 BacirbcL 作为硅藻的条码，并使用相应的引物对。考虑到 GenBank 中储存的序列有相当高的比例被错误标记，硅藻 DNA 条码的当务之急是使用正确鉴定的标本创建标准序列，理想情况下是模式标本。
