Table 4.
Paradoxical characteristics of ncRNAs in humans and mice [50, 51]. The excessive number of transcripts than anticipated for 25,000 genes indicates that the ncRNAs which were not detected due to scarce abundance have been detected by more sensitive methods. Some of these characteristics are summarized.
| Human | Mouse | |
|---|---|---|
| Gene Number | 75,000, 84,000 or 140,000 (cDNA identified) | |
| Transcripts | 181,000 | |
| Population | 50% Poly-A RNAs (of 16% genome) | 50% transcripts (of 62% genome) (35% from antisense strand) |
| Intron | 30% genome | |
| Processing | Polyadenylation, 5′ cap, splicing, nucleotide modification | |
| Transcripts from | Intergenic, Intronic regions and antisense strand | |
| Short ncRNAs | miRNA, siRNA (tasiRNA, natsiRNA), piRNA, rasiRNA (pitRNA), PARs (PROMTs, PASRs, TSSa-RNAs, tiRNAs), MSY-RNA, snoRNA, sdRNA, moRNA, tel-sRNA, crasiRNA, hsRNA, scaRNAs, AluRNA, YRNA, tRNA-derived RNAs | |
| Long ncRNA (lncRNA) (0.5–100 kb) | Cancers, disorders in skin, heart, brain, cerebellum, and so forth. TR/TERC, NEAT RNA (NEAT1v-1, NEAT1v-2, NEAT2/MALAT1), PINC RNA, DD3/PCA3, PCGEM1, SPRY4-1T1, xiRNAs (Xist RNA, Tsix RNA, RepA RNA), AIR, H19, KCNQ1ot1, HOTAIR, BORG, CTN RNA, ANRIL RNA, LINE, CSR RNA, satellite DNA transcripts and so forth | |
| Function | Regulatory function in all aspects of metabolism [52] | |