2007) (Fig. 2). Here, we explore the hypothesis that Pleistocene
sea-level fluctuations have strongly influenced the phylogeography and demography of the dugong in Australian waters. Alternatively, it is possible that any phylogeographical patterns have been obscured as a consequence of movement of dugongs leading to a degree of genetic homogeneity in the ~7,000 yr since the most recent flooding of Torres Strait. In support of this possibility, satellite-tagging studies have shown that individual dugongs are capable of long-distance movement covering hundreds of kilometers (Sheppard selleckchem et al. 2006). Knowledge of the extent to which dugong populations are interconnected will inform the debate about management of the species in Australia. Of particular interest is the spatial scale at which
it is legitimate to assess the eligibility of the species for listing under national and state legislation, which in turn determines the impact thresholds for government management action. The time-scales are within the reach of mitochondrial markers (Avise 1994) and we therefore present inferences from mitochondrial control region sequences. Mitochondrial sequence data constitute a single, maternally inherited marker. Ideally, biparentally inherited nuclear markers, such as microsatellites, should also be employed in a study like this. However, the material available to us, while adequate for amplification of the mitochondrial locus, often did not provide template however adequate for genotyping.
The work reported here extends that presented in two Ph.D. theses (Tikel 1997, Alvelestat in vitro McDonald 2005). These two authors each used DNA sequences from portions of the mitochondrial control region, as did we. Each found very strong evidence for the presence of two maternal lineages in Australia, as did we. One, the “widespread” lineage, occurs across the entire Australian range of the dugong, but is rare in southeastern Queensland. The “restricted” lineage was sampled primarily from the coast of Queensland. Samples were obtained opportunistically from dugongs from the full extent of the species’ range in Australia (Fig. 1, Table S1). Sources of material included dead stranded animals, animals taken by indigenous hunters, skin biopsies from live animals collected during satellite tagging experiments, and skin biopsies taken from free-ranging animals using a scraping device designed by Tikel (1997). Samples were also available from some dugongs from outside Australia (Table S1) to make a total of 188 (177 from Australia and 11 from elsewhere) for which a 411 bp portion of the control region was successfully sequenced (sequences with missing or ambiguous sites having been omitted). DNA extraction followed van Oppen et al. (1999) or used an Epoch GenCatch tissue kit (Epoch Biolabs Pty. Ltd.) following the manufacturer’s protocol. Initially, the “universal” forward primer L15926 (Kocher et al. 1989) and reverse primer A58 (5′ CCTGAAGTARGAACCAGATGTC 3′: Tikel et al.