Identification of suitable reference genes for normalization of quantitative real-time PCR-based gene expression in chicken (Gallus gallus).

The recent availability of genome information greatly facilitates the fundamental research on chicken. In different organs, gene expression patterns can provide clues to understanding the biological functions. For rapid and accurate quantification of gene expression, quantitative real-time PCR (qPCR) has become one of the most widely used methods. However, the success of qPCR data normalization depends on the use of a suitable reference gene and a single reference gene is not universally suitable for all the experiments. Therefore, reference gene validation is a crucial step for different organ tissues of chicken where suitable reference genes for qPCR analysis in varieties of tissues have not been investigated exhaustively so far. In this study, we have selected 30 Gallus gallus candidate reference genes from NCBI, amplified and studied their expression profiles by qPCR in different organ tissues (breast muscle, thigh muscle, heart, liver, spleen, gizzard, and bursa) of chicken. The result showed that, for breast muscle HSP10 and RPL23, thigh muscle RPL14 and RPL13, liver ALB and HSP70, spleen ALB and GAPDH, heart CYCS and TUBA8B, gizzard RPL5 and 18S rRNA, and bursa EEF1A1 and PGK2 are most stable genes respectively. The results also showed that for different organ tissues, individual or a combination of reference genes should be selected for data normalization. In this study, we have identified and validated 30 reference genes in seven different organ tissues to provide accurate transcript normalization and quantification, which can be useful for gene expression studies in other avian species.