Frequency of Heteroplasmy in Canine Mitochondria

Mitochondrial transmission has been traditionally thought to follow a strict matrilineal inheritance pattern.  This inheritance pattern reduces genetic diversity in the mitochondrial genome by prevention of recombination making the mitochondria particularly useful for evolutionary research.  However, recent advances in sequencing capabilities are challenging this tenet by showing evidence of higher than expected heteroplasmy frequencies.  Mitochondrial heteroplasmy, or the presence of more than one genomic haplotype, is commonly thought to be due to leakage of paternal mitochondria during fertilization.  The discovery that mitochondrial inheritance may not be strictly maternal has major implications for evolutionary studies.  For this reason, it is important to determine mitochondrial heteroplasmy frequencies across species.  In this study our objective was to determine the frequency of heteroplasmy in the canine mitochondrial genome.   Using sequence data generated with Illumina HiSeq and Illumina Genome Analyzer IIx we analyzed seventy-seven dogs for the presence of mitochondrial heteroplasmy.  We scanned the 16kb canine mitochondrial genome for variant patterns indicative of heteroplasmy.  Preliminary results indicate a low frequency of heteroplasmic individuals.