Molecular dating of caprines using ancient DNA sequences of <it>Myotragus balearicus</it>, an extinct endemic Balearic mammal

• Main Authors: Alcover Josep Antoni, Marquès-Bonet Tomàs, Sampietro Lourdes, Castresana Jose, Lalueza-Fox Carles, Bertranpetit Jaume
• Format: Article
• Language: English
• Published: BMC 2005-12-01
• Series: BMC Evolutionary Biology
• Online Access: http://www.biomedcentral.com/1471-2148/5/70

<p>Abstract</p> <p>Background</p> <p><it>Myotragus balearicus </it>was an endemic bovid from the Balearic Islands (Western Mediterranean) that became extinct around 6,000-4,000 years ago. The <it>Myotragus </it>evolutionary lineage became isolated in the islands most probably at the end of the Messinian crisis, when the desiccation of the Mediterranean ended, in a geological date established at 5.35 Mya. Thus, the sequences of <it>Myotragus </it>could be very valuable for calibrating the mammalian mitochondrial DNA clock and, in particular, the tree of the Caprinae subfamily, to which <it>Myotragus </it>belongs.</p> <p>Results</p> <p>We have retrieved the complete mitochondrial cytochrome <it>b </it>gene (1,143 base pairs), plus fragments of the mitochondrial 12S gene and the nuclear 28S rDNA multi-copy gene from a well preserved <it>Myotragus </it>subfossil bone. The best resolved phylogenetic trees, obtained with the cytochrome <it>b </it>gene, placed <it>Myotragus </it>in a position basal to the <it>Ovis </it>group. Using the calibration provided by the isolation of Balearic Islands, we calculated that the initial radiation of caprines can be dated at 6.2 ± 0.4 Mya. In addition, alpine and southern chamois, considered until recently the same species, split around 1.6 ± 0.3 Mya, indicating that the two chamois species have been separated much longer than previously thought.</p> <p>Conclusion</p> <p>Since there are almost no extant endemic mammals in Mediterranean islands, the sequence of the extinct Balearic endemic <it>Myotragus </it>has been crucial for allowing us to use the Messinian crisis calibration point for dating the caprines phylogenetic tree.</p>