Added an attrib type to define alternate three prime ends on a transcript

misc-scripts/attribute_types/attrib_type.txt

@@ -338,6 +338,9 @@
 # Intron loss due to a frameshift on the query genome
 198	lost_frameshift	lost_frameshift	Frameshift on the query sequence is lost in the target sequence
 
+# Transcript attribute to identify alternate three prime ends
+199	AltThreePrime	Alternate three prime end	The position of other possible three prime ends for the transcript
+
 #ÊAttributes added as gene_attribs to Ensembl genes that fall within a genomic region where a LRG record exists
 216	GeneInLRG	Gene in LRG	This gene is contained within an LRG region
 217	GeneOverlapLRG	Gene overlaps LRG	This gene is partially overlapped by a LRG region (start or end outside LRG)