step1. 安装软件rnaseqlib.
pip install –upgrade pip
pip install git+https://github.com/yarden/rnaseqlib.git
pip install gffutils
step2. 从UCSC下载ensGene.txt, knownGene.txt, refGene.txt到一个目录中，比如http://hgdownload.soe.ucsc.edu/goldenPath/danRer10/database/中的ensGene.txt.gz, refGene.txt.gz。下载完成后将它们解压缩。
step3. 运行命令：gff_make_annotation
比如 gff_make_annotation –genome-label “danRer10” –sanitize ~/Downloads/danRer10/UCSC ~/Downloads/danRer10/
