SRX824551 GSM1573616 SRP051569 SRS804166 GSM1573616 miRNA-Seq TRANSCRIPTOMIC size fractionation Total RNA was extracted from PL using the mirVana™ miRNA isolation kit (Ambion, Austin, TX, USA) following the manufacturer’s procedure. The quantity and purity of total RNA were monitored by NanoDrop ND-1000 spectrophotometer (Nano Drop, DE, USA) at 260/280 nm (ratio > 2.0). The integrity of total RNA was monitored by the Bioanalyzer 2100 and RNA 6000 Nano LabChip Kit (Agilent, CA, USA) with RIN number > 6.0. Equal quantities (5 µg) of small RNA isolated from three female Landrace pigs were pooled. Briefly, approximately 15 µg of small RNA was used for library construction and sequencing. The small RNA fragments (between 10-40 nt) were isolated by polyacrylamide gel electrophoresis (PAGE) and ligated with proprietary adaptors (Illumina, San Diego, CA, USA). The small RNA fractions were then converted to cDNA by RT-PCR and the cDNA was sequenced on the Genome Analyzer GA-II (Illumina) following the recommended manufacturer’s protocol. Illumina Genome Analyzer II GEO Sample GSM1573616 http://www.ncbi.nlm.nih.gov/geo/query/acc.cgi?acc=GSM1573616 gds 301573616 GEO Accession GSM1573616 SRX824552 GSM1573617 SRP051569 SRS804167 GSM1573617 miRNA-Seq TRANSCRIPTOMIC size fractionation Total RNA was extracted from PL using the mirVana™ miRNA isolation kit (Ambion, Austin, TX, USA) following the manufacturer’s procedure. The quantity and purity of total RNA were monitored by NanoDrop ND-1000 spectrophotometer (Nano Drop, DE, USA) at 260/280 nm (ratio > 2.0). The integrity of total RNA was monitored by the Bioanalyzer 2100 and RNA 6000 Nano LabChip Kit (Agilent, CA, USA) with RIN number > 6.0. Equal quantities (5 µg) of small RNA isolated from three female Landrace pigs were pooled. Briefly, approximately 15 µg of small RNA was used for library construction and sequencing. The small RNA fragments (between 10-40 nt) were isolated by polyacrylamide gel electrophoresis (PAGE) and ligated with proprietary adaptors (Illumina, San Diego, CA, USA). The small RNA fractions were then converted to cDNA by RT-PCR and the cDNA was sequenced on the Genome Analyzer GA-II (Illumina) following the recommended manufacturer’s protocol. Illumina Genome Analyzer II GEO Sample GSM1573617 http://www.ncbi.nlm.nih.gov/geo/query/acc.cgi?acc=GSM1573617 gds 301573617 GEO Accession GSM1573617 SRX824553 GSM1573618 SRP051569 SRS804168 GSM1573618 miRNA-Seq TRANSCRIPTOMIC size fractionation Total RNA was extracted from PL using the mirVana™ miRNA isolation kit (Ambion, Austin, TX, USA) following the manufacturer’s procedure. The quantity and purity of total RNA were monitored by NanoDrop ND-1000 spectrophotometer (Nano Drop, DE, USA) at 260/280 nm (ratio > 2.0). The integrity of total RNA was monitored by the Bioanalyzer 2100 and RNA 6000 Nano LabChip Kit (Agilent, CA, USA) with RIN number > 6.0. Equal quantities (5 µg) of small RNA isolated from three female Landrace pigs were pooled. Briefly, approximately 15 µg of small RNA was used for library construction and sequencing. The small RNA fragments (between 10-40 nt) were isolated by polyacrylamide gel electrophoresis (PAGE) and ligated with proprietary adaptors (Illumina, San Diego, CA, USA). The small RNA fractions were then converted to cDNA by RT-PCR and the cDNA was sequenced on the Genome Analyzer GA-II (Illumina) following the recommended manufacturer’s protocol. Illumina Genome Analyzer II GEO Sample GSM1573618 http://www.ncbi.nlm.nih.gov/geo/query/acc.cgi?acc=GSM1573618 gds 301573618 GEO Accession GSM1573618