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SUMMARY TABLES

	These tables 'summarize' the expression data for all of the signatures found in 
        our libraries. To determine the normalized abundance value for each signature in 
        the library, we separately merged 2-step runs and 3-step runs to create a raw 
        abundance count for each stepper. The raw abundance count was calculated as the 
        average from all 2-step or from all 3-step runs for a given signature. The average 
        total number of signatures sequenced in all 2-step or for all 3-step runs was also 
        calculated within the library. The final stage to merge the data within the steppers 
        was to calculate the normalized abundance for each stepper. The normalized abundance is 
        the raw abundance count divided by the average total number of signatures for both of
        the steppers in the library, multiplied by 250,000 to obtain a "transcripts per quarter 
        million" or TPQ value.

	The above method was applied separately for signatures matching to tRNAs, rRNAs, snRNAs 
        or snoRNAs. These signatures were removed from the primary set of small RNA signatures 
        and these data are in a different file (smallRNA_17_trsnosn_summary.txt).
	
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COLUMN HEADINGS

The summary table includes the following columns:

Signature  - 17nt smallRNA sequence
Hits       - is the number of occurrences of the signatures in the Arabidopsis genome 
FLR, etc.  - normalized data 
- see key to libraries on our web page. These values are normalized abundance, in transcripts per quarter (TPQ). The value was derived by a series of steps to merge the sequencing runs, described in above and in more detail in Meyers et al. (2004, Genome Research 14:1641) or Lu et al. (2005). 

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Questions regarding these data should be directed to Blake Meyers 
(meyers@dbi.udel.edu).