chr1	.	gene	1000	4000	.	+	.	gene_id "geneA"; gene_name "geneA";
chr1	.	transcript	1000	4000	.	+	.	gene_id "geneA"; transcript_id "transcriptA"; gene_name "geneA"; transcript_name "transcriptA";
chr1	.	exon	1000	2000	.	+	.	gene_id "geneA"; transcript_id "transcriptA"; exon_number "1"; gene_name "geneA"; transcript_name "transcriptA"; exon_id "exonA";
chr1	.	exon	3000	4000	.	+	.	gene_id "geneA"; transcript_id "transcriptA"; exon_number "1"; gene_name "geneA"; transcript_name "transcriptA"; exon_id "exonB";
