Plant & Animal Genomes XVII Conference

January 10-14, 2009
Town & Country Convention Center
San Diego, CA

Transcriptome Profiling Of Embryonic Development In Advance Backcross Introgression Lines Of Rainbow Trout

Peng Xu¹ , Lauren McIntyre² , Paul Wheeler³ , Gary Thorgaard³ , Krista Nichols¹

¹  Purdue University Department of Biological Sciences 915 W State Street West Lafayette, IN 47907 USA

²  University of Florida Department of Molecular Genetics and Microbiology Gainesville, FL 32610 USA

³  Washington State University School of Biological Sciences & Center for Reproductive Biology Pullman, WA 99163 USA

Embryonic development rate is a key trait significantly associated and genetically linked with both growth rate and sexual maturity in rainbow trout. To identify candidate genes underlying embryonic development rate, whole genome expression microarray analyses were conducted using embryos from a fourth generation backcross family; each backcross generation involved the introgression of the fast-developing alleles for the major development rate QTL (from the Clearwater clonal line [CW]) into a slow-developing clonal line (Oregon State University [OSU]). Embryos were collected at 15, 19, and 28 days post-fertilization. Microsatellite markers (One112ADFG, OMM1009 and OmyFGT12TUF) linked to the major embryonic development rate QTL region were used to determine the QTL genotype. The sex marker OMY-Y1 was used to determine the genotypic sex of each embryo. cDNA from 48 individual embryos were used for microarray expression analysis. An ANOVA modeling approach was used to detect differential gene expression between QTL genotypes, sex, and across time points. A total of 182 features have been identified with significant differences between embryonic development rate genotypes. Quantitative PCR was conducted on ten representative genes using the rainbow trout homologous sequences. For 9 of the 10 genes, the results between the qRT-PCR and microarray were in agreement. Notably, the genes associated with muscle contraction and development, including myosin light chain, troponin and parvalbumin family genes, were expressed significantly higher in the embryos with the fast-developing allele (CW) than those with the slow-developing allele (OSU), which may contribute the fast growth and body mass construction during embryonic development.