Optimized bisulfite sequencing reveals the lack of 5-methylcytosine in mammalian mitochondrial DNA [TAPS]

Whether 5mC exists in mitochondrial DNA is controversial, as data ranging from lack of 5mC to very extensive 5mC have been reported. By comprehensive bioinformatic analyses of published and our own data, we reveal that the observation of extensive and strand-biased mtDNA-5mC is artifact due to combinatorial effects of inefficient bisulfite conversion, extremely low sequencing reads in the L strand and interfering signals from nuclear mitochondrial DNA sequences (NUMTs). Overall design: DNA methylation analysis of TAPS data for listed cells and tissues.