Biodiversity lost: The phylogenetic relationships of a complete mitochondrial DNA genome sequenced from the extinct wolf population of Sicily

Abstract

Using next-generation sequencing, we obtained for the first time a complete mitochondrial DNA genome from a museum specimen of the extinct wolf (Canis lupus) population of the island of Sicily (Italy). Phylogenetic analyses indicated that this genome, which was aligned with a number of historical and extant wolf and dog mitogenomes sampled worldwide, was closely related to an Italian wolf mtDNA genome (the observed proportion of nucleotide sites at which the two sequences are different was p = 0.0012), five to seven times shorter than divergence among Sicilian and any other known wolf mtDNA genomes (p range = 0.0050 – 0.0070). Sicilian and Italian mitogenomes joined a basal clade belonging to the mtDNA haplogroup-2 of ancient western European wolf populations (Pilot et al., 2010). Bayesian calibration of divergence times indicated that this clade coalesced at MRCA = 13.400 years (with 95% HPD = 4000 – 21.230 years). These findings suggest that wolves probably colonized Sicily from southern Italy towards the end of the last Pleistocene glacial maximum when the Strait of Messina was almost totally dry. Additional mtDNA and genomic data will further clarify the origin and population dynamics before the extinction of wolves in Sicily.