## Description

This track shows various types of alternative splicing and other events that result in more than a single transcript from the same gene. The label by an item describes the type of event. The events are:

- Alternate Promoter (altPromoter) - Transcription starts at multiple places. The altPromoter extends from 100 bases before to 50 bases after transcription start.
- Alternate Finish Site (altFinish) - Transcription ends at multiple places.
- Cassette Exon (cassetteExon) - Exon is present in some transcripts but not others. These are found by looking for exons that overlap an intron in the same transcript.
- Retained Intron (retainedIntron) - Introns are spliced out in some transcripts but not others. In some cases, particularly when the intron is near the 3' end, this can reflect an incompletely processed transcript rather than a true alt-splicing event.
- Overlapping Exon (bleedingExon) - Initial or terminal exons overlap in an intron in another transcript. These often are associated with incompletely processed transcripts.
- Alternate 3' End (altThreePrime) - Variations on the 3' end of an intron.
- Alternate 5' End (altFivePrime) - Variations on the 5' end of an intron.
- Intron Ends have AT/AC (atacIntron) - An intron with AT/AC ends rather than the usual GT/AG. These are associated with the minor spliceosome.
- Strange Intron Ends (strangeSplice) - An intron with ends that are not GT/AG, GC/AG, or AT/AC. These are usually artifacts of some sort due to sequencing error or polymorphism.

## Credits

This track is based on an analysis by the `txgAnalyse` program of splicing graphs produced by the `txGraph` program. Both of these programs were written by Jim Kent at UCSC.