Sequence features of the population of tSMS reads recovered from sample TP (13,389 ± 52 BP). Sample TP was extracted in duplicate and identical volumes of the extracts were tSMS sequenced on a Helicos 110 FOV channels following different template preparation procedures as described in the methods section. The analyses are restricted to the fraction of reads identified as originating from the horse genome. Top: Read length distribution (spiked sequences are reported as vertical bars). Middle: Read GC contents. Right: Cumulative guanine to adenine misincorporation rates as a function of the distance from sequencing start. This class of mismatch derives from the post-mortem deamination of cytosine residues and can be taken as a proxy for post-mortem DNA damage.