Differential SAGE analysis in Arabidopsis uncovers increased transcriptome complexity in response to low temperature

Table 4 Distribution of the different types and frequency of alternative transcription events observed in the SAGE data.

	No. of Loci		No. of Events
	All alternative transcripts	Low temperature regulated (p < 001)	All alternative transcripts	Low temperature regulated (p < 001)
Modified Exon Order
Hits in same exon^a	105	23	268	67
Hits in different exon^a	173	26	453	78
Single non-canonical hit^b	547	67	547	67
Total	755	96	1223	188
Retained Introns
Within coding regions	233	29	298	38
3' UTR introns	768	95	1128	161
5' UTR introns	67	8	88	7
Total	1068	132	1514	206
Polymorphic UTRs
3' UTRs
Multiple SAGE tags	296	58	682	138
Single non-canonical hits^b	237	4	237	4
5' UTRs
Multiple SAGE tags	6	0	16	4
Single non-canonical hits^b	42	3	42	3

a. There will be some overlap between the alternate transcripts identified in these categories.
b. Due to the addition of virtual UTR sequence for a proportion of the loci it is possible that these categories may be overestimated.

ISSN: 1471-2164