DNA Sequence Identification Identify sequences by matching them against NCBI's BLAST nucleotide databases. Identify Identification Results Paste a sequence — this submits it directly to NCBI and opens the results page. No copy-paste needed. × Enter FASTA sequence(s) Paste raw sequence letters, or proper FASTA with ">" headers — both work. Keep total length modest; very large submissions should use NCBI's site directly. Reference database Nucleotide collection (core_nt) — general 16S ribosomal RNA (Bacteria & Archaea) Fungal/Plant ITS (broad) Fungal ITS (RefSeq, curated) Fungal 18S (SSU) Fungal 28S (LSU) Eukaryote 18S rRNA (SSU) Eukaryote 28S rRNA (LSU) RefSeq RNA (curated) Custom — type a database name… Search sensitivity Highly similar sequences (MegaBLAST) More divergent sequences (blastn) Advanced options Max matches to show Expect (E) threshold Reset Download .fasta Run BLAST