title: CK5
design: Small RNAs extracted from sperm samples were used to prepare sequencing library using NEBNext Small RNA Library Prep kit for Illumina (New England Biolabs) according to the manufacturers instructions. Amplified libraries were cleaned using Agencourt AMPure XP (Beckman Coulter), and RNAs with corresponding size were selected on a pre-casted 6% polyacrylamide Novex TBE gel (Invitrogen, Carlsbad, CA, USA). Disintegrated gels were incubated at 37 C for 1 h on a shaker, and were quickly frozen for 15 minutes at 80 C, followed by another incubation for 1 h. The libraries were then precipitated overnight at 80 C by adding 1 l of GlycoBlue (Invitrogen), 0.1 times the volume of Acetate 3M (pH 5.5), and 3 times the volume of 100% ethanol. After determining of library concentration using QuantiFluor ONE dsDNA system on a Quantus fluorometer (Promega, Madison, WI, USA), they were sequenced on an Illumina NextSeq 500 platform with NextSeq 500/550 High Output Kit v2 (77 cycles) (Illumina)