Genetic variation in functionally important domains of the bovine mtDNA control region

DNA sequences of the mitochondrial control region (CR) of 32 unrelated Austrian cattle were analysed in order to determine the extent of variability in functionally important domains. Using sequencing of PCR products, allele-specific PCR (AS-PCR) and primer introduced restriction analysis (PIRA), 43 differences were observed. They included 33 transitions, five transversions, one deletion and four differences in the number of consecutive cytosines. Twenty-three of these polymorphisms have not been reported before. In addition, we analysed all available European cattle sequences for this region. The transcriptional start sites, the conserved sequence block CSB 1 and both binding sites for the mitochondrial transcription factor mtTFA were highly conserved. We found a transition in each of the inter-specifically conserved Mt4 and Mt5 elements, three nucleotide substitutions in the termination-associated sequence TAS-A and six polymorphisms in the conserved sequence block CSB 2+3, a region which has been implicated in mitochondrial RNA processing.