PAG-XIV  Plant & Animal Genomes XIV Conference

January 14-18, 2006
Town & Country Convention Center
San Diego, CA


Poster: Microarrays

P724

Analysis Of Gene Expression During The Onset Of Muscle Hypertrophy In Callipyge Lambs

Jolena N Fleming1 , Lindsay M Wilson1 , Gayla R Olbricht3 , Tony Vuocolo2 , Keren Byrne2 , Bruce A Braig3 , Ross L Tellam2 , Noelle E Cockett4 , Christopher A Bidwell1

1  Dept. of Animal Sciences Purdue University 125 S. Russell West Lafayette, IN 47907 USA
2  CSIRO Livestock Industries 306 Carmody Rd. St. Lucia, QLD 4067 Australia
3  Department of Statistics Purdue University 150 N. University Street West Lafayette, IN 47907-2067 USA
4  ADVS Department Utah State University 4815 Old Main Hill Logan UT 84322-4815 USA

The callipyge mutation causes postnatal muscle hypertrophy in lambs that inherit a paternal callipyge allele and are heterozygous (+/CPat). Our hypothesis was that the up regulation of one or both of the 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 callipyge phenotype. Total RNA was isolated from the longissimus dorsi of two callipyge (+/CPat) and two normal (+/+) lambs at 10d, 20d, and 30d of age. Muscle weight data indicated that hypertrophy of the longissimus had begun at 30d. Gene expression was measured using the Affymetrix Bovine Genome Expression Array and no alterations were made to the protocol for cross-species hybridization. An average of 9,796 probes sets (40.6%) was detected. A total of 14,850 genes were detected present on at least one chip and included in the analysis. A log base-2 transformation was performed on data before normalization both for signal intensity within chip and probe set signal across all chips. A two-way ANOVA for genotype and age effects and the Benjamini and Hochberg False Discovery Rate method was used for an overall p-value of 0.10. From the ANOVA, 14 genes were significant for genotype effect and 13 were significant for age effect (P < 0.10). No significant age by genotype interactions were detected (P > 0.10).