title: GSM5511040: High milk protein percentage phenotype in lactation_rep1; Bos taurus; miRNA-Seq
library_construction_protocol: Total RNA was extracted using TRIzol reagent (Invitrogen, Carlsbad, CA, USA). Twelve small RNA libraries from RNA integrity and concentration were assessed using the RNA Nano 6000 Assay Kit of the Bioanalyzer 2100 system (Agilent Technologies, CA, USA). All RNA samples had an RNA integrity number of at least 7.5. 15% agarose gels separated total RNA to extract the small RNA (18-30 nt). After precipitated by ethanol and centrifugal enrichment of small RNA sample, the library was prepared according to the method and process of Small RNA Sample Preparation Kit (Illumina, RS-200-0048). RNA concentration of library was measured using Qubit® RNA Assay Kit in Qubit® 2.0 to preliminary quantify and then dilute to 1 ng/μl. Insert size was assessed using the Agilent Bioanalyzer 2100 system (Agilent Technologies, CA, USA). After the insert size consistent with expectations, the qualified insert size was accurate quantitative using the Taqman fluorescence probe of AB Step One Plus Real-Time PCR system (Library valid concentration>2 nM). The qualified libraries were sequenced by an Illumina Hiseq 2500 platform and generate 50 bp single-end reads.