Prep Kits for Illumina Systems

	mRNA sequencing	Whole-transcriptome sequencing
Applications	Detect coding RNA Gene expression Gene fusions Transcript isoforms	Most complete understanding of phenotype Detect coding and noncoding RNA Gene expression Alternative gene expression Gene and transcript abundance Biomarker identification
Reads per sample (millions)	30	60
Hands-on time (hours)	1.5	3.5
Total time (hours)	4.5	6.5
Input range	1–25 ng**	100–1000 ng
FFPE compatible?	Yes	Yes
Species compatibility	All	Human, mouse, rat Plants, bacteria

* Inputs of >200 ng are recommended for efficient detection of low abundance transcripts.
** rRNA depleted or mRNA enriched RNA

Variation in RNA-seq expression data can be attributed to a variety of factors ranging from the quality of the starting material to the person performing the experiment. The External RNA Controls Consortium (ERCC), an ad-hoc group of academic, private, and public organizations hosted by the National Institute of Standards and Technology (NIST), developed a common set of external RNA controls to distinguish between these sources of variability and true gene expression. The controls consist of a set of unlabeled, polyadenylated transcripts designed to be added to an RNA sequencing experiment after sample isolation in order to measure against defined performance criteria.

The Invitrogen ERCC Spike-In Mix is a pre-formulated blend of 92 transcripts, derived and traceable from NIST-certified DNA plasmids. The transcripts mimic natural eukaryotic mRNAs of 250 to 2,000 nt in length. Inclusion of ERCC controls in RNA sequencing experiments establishes a standard measure for data comparison across gene expression experiments and makes it possible to measure sensitivity (lower limit of detection) and dynamic range of an experiment.