MEGAN software, percent identity

Question

[donkichote]

Hi,

I'm using the BLAST output in MEGAN software. It's metabarcoding (barcode region of cytochrome oxidase 1, COI) data on insects. Do anyone have an idea, why the option "use identity percent filter" in MEGAN is suppose to be used only for the 16S gene and not anything else? why it can't be use for the COI gene?

Thanks,