I need a gtf annotation file. UCSC doesn't give us a proper gtf file with distinct gene_id and transcript_id. It asked us to get a genePred file to convert to gtf.
But where can we get genePred files?
It turned out that using table browser on UCSC we could download an output with all fields. That output actually contains a GenePred file but has one extra column on the left end.
The genePred file format definition is here.