empty output of cds.fa

[Liyong]

Hello,

I am using gffread (v0.12.7) to extract transcript sequences based on a stringtie merged gtf file.
After looking through gffread's usage, I want to use -w to extract sequences of exons, and -x to extract cds.
My command are as following:
gffread -w exon.fa -x cds.fa -g genome stringtie_merged.gtf

The result exon.fa seems fine, but cds.fa is an empty file. I am wondering is there anything I can do about this.

Thanks a lot,
Liyong

[Gao Xinlong]

这是因为注释第三列中没有CDS的注释，所以生成的cds.fa肯定为空，蛋白质序列生成似乎是基于cds.fa的，故也为空