Microarray Analysis Of Skeletal Muscle At Four Stages In Yorkshire And Meishan Pigs

Pork is an important source of animal protein, while swine as an experimental model in human healthcare researches is homologous to human being. Thus a better understanding of porcine skeletal muscle growth and development is of considerable significance for meat production science and human medical research.Skeletal muscle is the most abundant form of tissue in vivo, which traits of growth and development deserves closest study in meat livestock science. The experiment herein is based on the contrast of porcine muscles between the fast growing Yorkshire breed with poor texture and slow-growing Meishan breed with better texture. Skeletal muscle is the most abundant tissue in the animals, and its characters related to growth are the foremost ones. In this research,we used gene chip to analyze the differences of genes expression about Longissimus Dorsi Muscle between Yorkshier (Y),which have faster growth speed and worse meat quality, and Meishan (M) which have opposite characters. We compared the transcriptional profile of porcine longissimus dorsi muscle at65days post coitus,3days,60days and120days post natal between Meishan and Yorkshire pigs using microarrays. In order to investigate the molecular mechanisms underlying porcine skeletal muscle growth and development and meat quality traits, some work had been done. The results are as follows:1. We used swine whole genome Affymetrix oligo chip contained23937probes to detect the genes differentially expressed in the Longissimus Dorsi Muscle between12Large white pigs and12Meishan pigs which are at65days post coitus,3days,60days and120days post natal. According to multiple comparison, we screened related genes that had statistical significance(P<0.01) SAM result showed that:At65dpc,1495probes representing195genes were up regulated while626probes representing44genes were down regulated in Meishan pig vs Yorkshire. At3dpn,867probes representing81genes were up regulated while559probes representing90genes were down regulated in Meishan vs Yorkshire. At60dpn,1617probes representing125genes were up regulated while927probes representing174genes were down regulated in Meishan vs Yorkshire. At120dpn,287probes representing25genes were up regulated while432probes representing76genes were down regulated in Meishan vs Yorkshire. Most genes differentially expressed at65days post coitus and60days post natal, while few genes at120days post natal, suggesting65days post coitus and60days post natal as important stages leading to differences in meat quality traits between Meishan and Yorkshire pigs. 2. To obtain insight in the kinetics of the gene regulation during the four time pionts of each breed, all the expressed genes from each breed at65days post coitus,3days,60days and120days afterbirth were irrespectively organized into12clusters, c0through cll, using SOM analysis3. According to the profile and its similarity, we combined pattern pattern c7and c11as pattern P1,c1, c2and c5as pattern P2and pattern c4, c8and c9as pattern P3in Meishan. While we also combined pattern c0as P1, c2, c3, c5, c7as P2, c6, c9, c10,c11as P3, c8as P4in Yorkshier. Genes like:COL5A1, CASP3, FMOD, EGFR reached their expression peak at65dpc in both breeds. ACADL, ACADM, ACSL1, CPT1B, FABP3, FBP reached their expression peak at3dpn in both breeds. EGF, CAPN3, LIM, LPL reached their expression peak at60dpn in both breeds. ALDH2, GHR reached their expression peak at120dpn in both breeds. These genes share similar expression pattern between two breeds showed their importance during pig muscle development.4. According to ways of classifying expression pattern, we made one time point expression peak miss match comparison between two breeds. Result showed that:CTGF, COL3A1, IGF2, IPM3reached their expression peak at65dpc in Meishan pig while at3dpn in Yorkshire. ACSL4, FABP4, HSP70, MYF6reached their expression peak at3dpn in Meishan pig while at60dpn in Yorkshire. ALDH2, GHR reached their expression peak at60dpn in Meishan pig while at120dpn in Yorkshire.5. We elaborated the regulation mode during the porcine growth and development on the molecular level and the differences of genes'express pattern between two pig breeds through genes associated with apoptosis, muscle formation, muscle growth and development, glycogen metabolism, glycolysis and fatty acid metabolism form the data analysis of gene expression network by Molecule Annotation System.6. More information could be obtained comparing transcriptome data with proteome data of longissimus dorsi muscle at four developmental stages of Meishan pigs, and the transcriptional data was consistent with the proteomic data of Meishan pig.