Preliminary qRT-PCR experiments carried out to set up optimal reaction conditions showed that all candidate reference genes were expressed in ovine whole blood. qRT-PCR optimisation was performed using pooled cDNA samples in parallel with sheep genomic DNA. All primer pairs spanned two exons, generating melt-curve profiles specific to cDNA and genomic DNA amplification. While this strategy entailed much more effort in primer design and reaction optimisation, it assured specific amplification of mRNA transcripts by avoiding/recognizing interference of genomic DNA in quantification. Actually, in most cases DNAse treatment does not completely eliminate genomic DNA contamination, especially when RNA extraction is performed using reagents based on mono-phasic solution of phenol and guanidine isothiocyanate (personal observation). Gene-specific amplification was confirmed for all selected genes by a single-peak in melt-curve analysis and subsequent sequencing of amplicons. The determined reference gene sequences have been submitted to the GenBank database under the accession numbers JN811677-JN811687.