Regarding ArgumentError: cannot create a mer with ambiguous nucleotides

[PRIYANKA-22091995]

Hello Sir, I was trying to run the first command i.e. julia bin/whippet-index.jl --fasta hg19.fa.gz --gtf anno/gencode_hg19.v25.tsl1.gtf.gz, but it is showing the following error constantly.It would be nice have your insights on the same. Note-Both the fasta file and gtf file was downloaded from ensembl.

Thanks & Regards Priyanka Roy