Analysis of gene expression during the onset of muscle hypertrophy in callipyge lambs: time course. Ovis aries

The callipyge mutation causes postnatal muscle hypertrophy in heterozygous lambs that inherit a paternal callipyge allele (+/CLPG). Our hypothesis was that the up-regulation of one or both of the affected paternally expressed genes (DLK1 or PEG11) initiates changes in biochemical and physiological pathways in skeletal muscle to induce hypertrophy. The goal of this study was to identify changes in gene expression during the onset of muscle hypertrophy in order to identify the pathways that are involved in the expression of the callipyge phenotype. Gene expression was analyzed in longissimus dorsi total RNA from lambs at 10, 20, and 30 days of age using the Affymetrix Bovine Expression Array. Keywords: time course Overall design: Longissimus dorsi were collected from 10, 20, and 30 day old callipyge and normal lambs with 2 biological replicates for each group. Total RNA was isolated and hybridized to Affymetrix Bovine Expression arrays. Data were analyzed in SAS and all genotype effects were followed up by qPCR in 42 lambs ranging from 10 to 200 days of age.