A first complete catalog of highly expressed genes in eight chicken tissues reveals uncharacterized gene families specific for the chicken testis.

Based on next-generation sequencing, we established a repertoire of differentially overexpressed genes (DoEG) in eight adult chicken tissues: testis, brain, lung, liver, kidney, muscle, heart, and intestine. With 4499 DoEG, the testis had the highest number and proportion of DoEG compared with the seven somatic tissues. The testis DoEG set included the highest proportion of long noncoding RNAs (lncRNAs; 1851, representing 32% of the lncRNA genes in the whole genome) and the highest proportion of protein-coding genes (2648, representing 14.7% of the protein-coding genes in the whole genome). The main significantly enriched Gene Ontology terms related to the protein-coding genes are "reproductive process," "tubulin binding," "microtubule cytoskeleton." By using real-time quantitative reverse transcription polymerase chain reaction, we confirmed the overexpression of genes that encode proteins already described in chicken sperm (such as