cDNA array analysis of Japanese quail lines divergently selected for four-week body weight

Department of Genetics, University of Georgia, Athens, Georgia 30602-7223, USA.

Decades of divergent selection for 4-wk BW has produced 3 lines of growth-selected Japanese quail. P line quail have been selected for >110 generations for 4-wk posthatch BW and are nearly 3-fold larger than the randomly bred control C line. The H line has been selected for high 4-wk BW for 52 generations and the L line has been selected for low 4-wk BW for 54 generations. To identify differentially expressed genes that may play a role in defining the differences in these lines, a DNA array containing 4,704 random anonymous cDNA clones from 8-d C line embryos was screened using isotopically-labeled cDNA from the different quail lines. Array analysis yielded 3 differentially expressed cDNA clones that were confirmed by Northern blot analysis. The 35-kD quail EB1 protein, previously unidentified, was shown to have elevated transcripts in the L line and decreased transcripts in the H and P lines, compared with the C line. It was also widely expressed in embryonic and adult tissues by BLASTN analysis of chicken expressed sequence tag (EST) libraries. Two other cDNA clones are novel sequences expressed at higher levels in the L line and at lower levels in the H and P lines, one of which was more selectively expressed in embryos and adult tissues by BLASTN analysis. These limited findings suggest that anonymous cDNA array analysis is a productive means to identify differentially expressed genes in growth-selected poultry.