A FASTQC report shows an overrepresented sequence defined as "Truseq adapter"
but when I BLAST its nucleotide sequence (GATCGGAAGAGCACACGTCTGAACTCCAGTCACGTCGGAGCATCTCGTAT)
it aligns with high confidence to, say, coronavirus genes
Why is that? I was expecting to see the top hit saying something like "Illumina Adapter".
And also why the nucleotide sequence reported by FastQC as "truseq adapter 18" doesn't match it's namesake in one listed in Illumina's official document??????
I am asking this because i wanted to BLAST the overrepresented sequences in my data and see if they come from the ribosomal RNA contamination or not. And with results like THAT even for the adapter sequences I clearly don't understand something