European Hake Mitogenome Sequencing

DNA was extracted from muscle tissue samples as previously described [11 ],[38 (link)],[42 (link)],[48 ]. DNA for complete mitogenome sequencing of European hake was extracted from frozen muscle tissue by using the mtDNA Extractor CT Kit from Wako [42 (link)]. The PCR and sequencing primers (Additional file 8: Table S2) applied in the European hake sequencing were designed from the published Atlantic cod mitogenome sequence [21 (link)] and other available gadiform sequences (Additional file 3: Table S1). These primers were used to amplify the mitogenomes in 1 to 4 kb fragments essentially as described by [11 ]. The primer pair L15498/H15666 was used for amplification of the T-P spacer from most species. For European hake, a specific primer set (L15498/H15642) was designed for T-P spacer amplifications. The PCR products were treated with exonuclease and shrimp alkaline phosphatase (USB) prior to plasmid cloning and sequencing. The amplified fragments were subcloned into the SmaI-site of pUC18 vector using the Sure-Clone Ligation kit (Pharmacia Biotech).