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Evolutionary relationships and divergence times among the native rats of Australia


Robins, JH and McLenachan, PA and Phillips, MJ and McComish, BJ and Matisoo-Smith, E and Ross, HA, Evolutionary relationships and divergence times among the native rats of Australia, BMC Evolutionary Biology, 10 Article 375. ISSN 1471-2148 (2010) [Refereed Article]


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Licensed under Creative Commons Attribution 2.0 Generic (CC BY 2.0)

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DOI: doi:10.1186/1471-2148-10-375


Background: The genus Rattus is highly speciose and has a complex taxonomy that is not fully resolved. As shown previously there are two major groups within the genus, an Asian and an Australo-Papuan group. This study focuses on the Australo-Papuan group and particularly on the Australian rats. There are uncertainties regarding the number of species within the group and the relationships among them. We analysed 16 mitochondrial genomes, including seven novel genomes from six species, to help elucidate the evolutionary history of the Australian rats. We also demonstrate, from a larger dataset, the usefulness of short regions of the mitochondrial genome in identifying these rats at the species level.
Results: Analyses of 16 mitochondrial genomes representing species sampled from Australo-Papuan and Asian clades of Rattus indicate divergence of these two groups ~2.7 million years ago (Mya). Subsequent diversification of at least 4 lineages within the Australo-Papuan clade was rapid and occurred over the period from ~ 0.9-1.7 Mya, a finding that explains the difficulty in resolving some relationships within this clade. Phylogenetic analyses of our 126 taxon, but shorter sequence (1952 nucleotides long), Rattus database generally give well supported species clades.
Conclusions: Our whole mitochondrial genome analyses are concordant with a taxonomic division that places the native Australian rats into the Rattus fuscipes species group. We suggest the following order of divergence of the Australian species. R. fuscipes is the oldest lineage among the Australian rats and is not part of a New Guinean radiation. R. lutreolus is also within this Australian clade and shallower than R. tunneyi while the R. sordidus group is the shallowest lineage in the clade. The divergences within the R. sordidus and R. leucopus lineages occurring about half a million years ago support the hypotheses of more recent interchanges of rats between Australia and New Guinea. While problematic for inference of deeper divergences, we report that the analysis of shorter mitochondrial sequences is very useful for species identification in rats.

Item Details

Item Type:Refereed Article
Research Division:Biological Sciences
Research Group:Evolutionary biology
Research Field:Animal systematics and taxonomy
Objective Division:Expanding Knowledge
Objective Group:Expanding knowledge
Objective Field:Expanding knowledge in the biological sciences
UTAS Author:McComish, BJ (Dr Bennet McComish)
ID Code:96192
Year Published:2010
Web of Science® Times Cited:34
Deposited By:Mathematics and Physics
Deposited On:2014-10-22
Last Modified:2014-11-25
Downloads:348 View Download Statistics

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