## how data in inst/extdata was generated
"CD1A.RNAseq.metadata.txt"" -- an toy metadata file, containing columns
   sample_name (unique sample names)	
   group	   (experimental treatment groups, consisting of alphabets 
                and/or numbers)
   batch       (sample processing batch)	
   BAM_file	   (path to BAM files)
   salmon_quant_file   (path to quant.sf files generated by Salmon)

"K084CD7PCD1N.quant.sf" and "K084CD7PCD1P.quant.sf" -- Reads in the fastq files
   under accession numbers SRR28197543 (BioSample GSM812276, REL-14 hL-IC Rep 3)
   and SRR28197542 (Biosample GSM8122767, REL-14 DP Rep 3) were trimmed 
   using Trimmomatic, and mapped to the human transcriptome decoyed by the
   primary assembly of the human reference genome GRCh38.p14 (Release 110)
   using Salmon. The rsulting quantification files (.sf) files are inlcuded
   for demonstration purpose. Scripts used for generating the quantification
   files is available at Git Hub repositoru: https://t.ly/LVjj7.

"K084CD7PCD1N.srt.bam" and "K084CD7PCD1P.srt.bam" -- Reads in the fastq files
   under accession numbers SRR28197543 (BioSample GSM812276, REL-14 hL-IC Rep 3)
   and SRR28197542 (Biosample GSM8122767, REL-14 DP Rep 3) were trimmed 
   using Trimmomatic, and aligned to the primary assembly of the human
   reference genome GRCh38.p14 (Release 110) using STAR. The resulting BAM
   files were coordinate-sorted. Reads aligned to chromosome 19 were extracted
   using the SAMtools view command to get the subsetted BAM files for 
   demonstration purpose. Scripts used for generating the BAM files is 
   available at Git Hub repositoru: https://t.ly/LVjj7.
   

"example.gtf.gz" -- the first 505 lines of the GTF file for the primary assembly
   of the human reference genome GRCh38.p14, Release 110 (https://t.ly/THHdJ)
   downloaded from Ensembl. 