6 to 24 RPKM (reads per kilobase of mappable length per million mapped reads) corresponds to

Range ~1 mRNA molecule/cell
Organism Chlamydomonas reinhardtii
Reference Castruita M et al., Systems biology approach in Chlamydomonas reveals connections between copper nutrition and multiple metabolic steps. Plant Cell. 2011 Apr23(4):1273-92. doi: 10.1105/tpc.111.084400. abstract & p.1284 right column top paragraphPubMed ID21498682
Method Abstract:"In this work, [investigators] query the Chlamydomonas reinhardtii copper regulon at a whole-genome level. [Their] RNA-Seq data simulation and analysis pipeline validated a 2-fold cutoff and 10 RPKM (reads per kilobase of mappable length per million mapped reads) (~1 mRNA per cell) to reveal 63 CRR1 targets plus another 86 copper-responsive genes."
Comments p.1284 right column top paragraph:"A comparison of technical replicates (individual lanes in a flow cell) or library types (single read versus paired end) and experimental replicates resulted in a very high degree of reproducibility. While [investigators] did not include standards for the determination of absolute transcript abundance, in previous work [they] estimated a copy number of 1 to 4 × 10^2 for the CYC6 transcript in copper-deficient cells (Hill and Merchant, 1992). On this basis, [they] can calculate that 6 to 24 RPKM is approximately equivalent to 1 mRNA molecule per cell. Given that the median transcript abundance is 5.6, this means that half of the genes have transcripts with copy numbers of only 1 per cell in a typical laboratory batch culture."
Entered by Uri M
ID 111774