-Some aligners' (other than Bowtie) output might need to be converted
-so that RSEM can use. For conversion, please run
+RSEM requires all alignments of the same read group together. For
+paired-end reads, RSEM also requires the two mates of any alignment be
+adjacent. If the alternative aligner does not satisfy the first
+requirement, you can use 'convert-sam-for-rsem' for conversion. Please run