Table 3.

Classification of gene models into different groups based on their relative location to other genes, number of isoforms and other criteria

	Name	Description
Group 1	Uni-exon transcripts	Transcripts having a single exon and no introns
Group 2	Transcripts without UTRs	Transcripts missing either the 5′ or the 3′ UTR sequence
Group 3	Transcripts with UTRs	Transcripts having both UTRs
Group 4	Transcripts with micro-exons	Transcripts where at least one exon has length less than 50 nucleotides
Group 5	Transcripts with long introns	Transcripts where at least one intron has a length greater than 10,000 bp
Group 6	Closely placed transcripts on same strand	Transcripts on the same strand having less than 250 nucleotides between each other
Group 7	Closely placed transcripts on opposite strand	Transcripts on the opposite strands having less than 250 nucleotides between each other
Group 8	Multi transcript gene	Transcripts of a gene that have multiple transcripts
Group 9	Single transcript gene	Transcripts of a gene that have single transcript