Phylogenetics, population structure and genetic diversity of the endangered southern brown bandicoot (Isoodon obesulus) in south-eastern Australia

Abstract

The southern brown bandicoot (Isoodon obesulus) has undergone significant range contractions since European settlement, and it is now considered ''Endangered'' throughout south-eastern mainland Australia. This species currently has a highly fragmented distribution inhabiting a mosaic of habitats. This project uses mitochondrial DNA (mtDNA) and microsatellite data to determine levels of genetic diversity, population structure and evolutionary history, which can aid wildlife managers in setting priorities and determining management strategies. Analyses of genetic diversity revealed low levels of mtDNA variability (mean h ¼ 50.42%, p ¼ 0.76%) and divergence (mean d A ¼ 0.29%) across all regions investigated, and was among the lowest recorded for marsupials. These data indicate a relatively small female effective population size, which is most likely a consequence of a large-scale population contraction and subsequent expansion occurring in pre-history (mismatch distribution analysis, SSD P-value ¼ 0.12). Individuals from the Sydney region experienced significant reductions in microsatellite diversity (A ¼ 3.8, H E ¼ 0.565), with the Garigal National Park (NP) population exhibiting ''genetic reduction signatures'' indicating a recent population bottleneck. Population differentiation analysis revealed significant genetic division amongst I. obesulus individuals from Sydney, East Gippsland and Mt Gambier regions (h ¼ 0.176-0.271), but could not separate the two Sydney populations (Ku-ring-gai NP and Garigal NP). Based on these data and habitat type, translocations could readily be made between the two Sydney populations, but not between the others. Phylogenetic comparisons between I. obesulus and I. auratus show little support for current Isoodon taxonomy, consistent with the findings of Pope et al. 2001. We therefore recommend the recognition of only three I. obesulus sub-species and suggest that these comprise a single morphologically diverse species that once was widespread across Australia.

Microsatellite Markers forAleurocanthus spiniferus(Hemiptera: Aleyrodidae) and Their Potential use in Whiteflies

“…In the field of entomology, it has been used for gene mapping, population genetic structure analysis, identification of genetic relationships, and genetic map constructions (Gorman 1997;Zenger et al 2005). In this study, we developed 10 high polymorphic microsatellite markers for A. spiniferus, and crossspecies amplifications were also conducted of the 5 closely related whitefly species (Aleurodicus disperses Russell, Pealius mori Takahashi, Aleuroclava aucubae Kuwana, Bemisia tabaci (Gennadius) MEAM1 and B. tabaci MED).…”

Mitochondrial DNA reveals low population differentiation in elongate loach, Leptobotia elongata (Bleeker): implications for conservation

“…Several molecular markers have been used in the assessment of genetic diversity of fishes (Wasko and Galetti-Jr 2002;Zenger et al 2005;Mandal et al 2009). Among them, the mitochondrial DNA (mtDNA) control region has been used widely to investigate both population genetic structure and variability because of its rapid evolutionary rate (Nyakaana et al 2002;Sato et al 2004;Chen et al 2006).…”

Extensive genetic differentiation detected within a model marsupial, the tammar wallaby (Notamacropus eugenii)

“…eugenii populations and the lack of recent gene flow between them, allowing each to evolve independently. A similar pattern of genetic divergence is also present between eastern and western populations (or species pairs) in many taxa across southern Australia, including grey kangaroos [66], dasyurids [67,68], bandicoots [69], rodents [70], birds [71–73] and reptiles [74]. This widespread pattern of east/west divergence is believed to reflect the separation of mesic fauna by the arid Nullarbor Barrier, as a consequence of the increasing aridity of Australia during the Pleistocene [75,76].…”