The novel 172 sheep (Ovis aries) microRNAs and their targets

MicroRNAs (miRNAs) are small, non-coding and regulatory RNAs about ≈22 nucleotides in length. The comparative genomics approach due to their conserved nature is a good source for the novel miRNAs discovery. In this study, total 172 novel miRNAs from 140 precursor sequences belonging to 114 families were identified in sheep (Ovis aries), the most important livestock animal. All the miRNA families (oar-mir-95, 129, 130, 186, 214, 219, 223, 324, 339, 423, 450, 499, 544, 562, 568, 584, 669, 671, 763, 935, 1281, 1282, 1306, 1552, 1584, 1587, 1603, 1607, 1706, 1711, 1718, 1732, 1738, 1761, 1771, 1777, 1778, 1780, 1807, 1843, 1895, 1930, 2127, 2139, 2182, 2284, 2287, 2295, 2296, 2310, 2311, 2314, 2315, 2316, 2320, 2359, 2378, 2381, 2382, 2395, 2400, 2404, 2410, 2412, 2423, 2426, 2435, 2470, 2477, 2482, 2487, 2881, 2883, 2885, 2888, 2889, 2896, 2901, 2904, 2917, 2964, 3063, 3064, 3074, 3080, 3432, 3529, 3533, 3613, 3649, 3654, 3658, 3661, 3662, 3940, 3960, 4273, 4426, 4447, 4459, 4468, 4493, 4507, 4647, 4680, 4785, 4788, 4800, 5102, 5105, 5109, 5115, 5125 and 5132) are found for the first time in Sheep. All 140 miRNA precursors form stable minimum free energy stem loop and the mature miRNAs reside in the stem portion of the stem loop structure. Their putative targets are involved in transcription factors (26%), signaling (19%), metabolism (18%), transportation (10%), immunity (9%), cancer and tumor related (5%), growth and development (5%), stress related (4%), and structural proteins (3%).