Fig. 2.

Stochastic detection and assembly of lncRNAs by RNA-seq libraries. These results—a consequence of limitations in sequencing breadth and depth—suggest that for a given species, only a subset of the total lncRNA transcriptome is likely to be captured. Nevertheless, the number of candidate lncRNAs for that species can be increased if directly mapping, to a positionally conserved region of the genome, the lncRNAs from either a related (sheep, goat, cattle) or more distant (human) species. Many of these mapped lncRNAs (which could not be completely reconstructed with the RNA-seq libraries of that species) are nevertheless detectably expressed