Diatom taxa identification based on single-cell isolation and rDNA sequencing

Abstract The identification of diatom taxa can provide important clues for criminal investigation. We developed a single cell rDNA amplification and sequence-based method to diagnose diatom taxon. Single cell of Synedra sp. was isolated under the microscope. A fragment containing the V4 region of 18S rDNA, shorter than 500bp, was amplified using universal primers (D512for 18S+D978rev 18S) and sequenced. Uncorrected p -distances were computed using MEGA5.0 with 451 reference sequences, which identified the diatom's genera but failed to diagnose with species. This method could supplement the conventional morphological diatom test for forensic application. But the retrieval rate for correct identifications depends on the sequence information in reference database and barcode markers.