Molecular assessment of the genetic integrity, distinctiveness and phylogeographic context of the Saltwater crocodile (Crocodylus porosus) on Palau

Russello, M. A., Brazaitis, P., Gratten, J., Watkins-Colwell, G. J. and Caccone, A. (2007) Molecular assessment of the genetic integrity, distinctiveness and phylogeographic context of the Saltwater crocodile (Crocodylus porosus) on Palau. Conservation Genetics, 8 4: 777-787. doi:10.1007/s10592-006-9225-7


Author Russello, M. A.
Brazaitis, P.
Gratten, J.
Watkins-Colwell, G. J.
Caccone, A.
Title Molecular assessment of the genetic integrity, distinctiveness and phylogeographic context of the Saltwater crocodile (Crocodylus porosus) on Palau
Formatted title
Molecular assessment of the genetic integrity, distinctiveness and phylogeographic context of the Saltwater crocodile (Crocodylus porosus) on Palau
Journal name Conservation Genetics   Check publisher's open access policy
ISSN 1566-0621
1572-9737
Publication date 2007-08-01
Year available 2007
Sub-type Article (original research)
DOI 10.1007/s10592-006-9225-7
Open Access Status
Volume 8
Issue 4
Start page 777
End page 787
Total pages 11
Place of publication Dordrecht, Netherlands
Publisher Springer Netherlands
Language eng
Abstract The saltwater crocodile (Crocodylus porosus) is the largest and most broadly distributed crocodilian species, and thus is of special conservation and economic interest. Similar to other parts of its range throughout the Indo-Pacific, C. porosus distributed in the Republic of Palau have experienced a severe population decline over the past century primarily due to commercial hunting and eradication campaigns. In addition, several thousand crocodiles of undocumented species and origin were imported into Palau during the 1930's for commercial farming purposes, potentially polluting the gene pool of the endemic saltwater crocodiles. Analysis of 39 individuals collected throughout the Republic of Palau revealed a single mitochondrial DNA control region haplotype shared by populations sampled in Sulawesi, Borneo and Australia. The mtDNA results, in combination with microsatellite genotypic data at six loci, detected no evidence for inter-specific hybridization between endemic Palauan C. porosus and potentially introduced Crocodylus species. There was no evidence for a genetic bottleneck in the Palauan population, however an excess of rare alleles was identified, indirectly suggesting a recent history of admixture potentially linked to introductions of non-native C. porosus. Following from these findings, Palauan C. porosus should be included in the single ESU previously established for all saltwater crocodiles given the recovery of a fixed, but geographically widespread haplotype. Although Palauan C. porosus exhibited significant genetic differentiation relative to all other sampled populations, it's delineation as a distinct management unit is precluded at the present time by evidence that the genetic integrity of the population may have been compromised by the introduction of non-native saltwater crocodiles.
Formatted abstract
The saltwater crocodile (Crocodylus porosus) is the largest and most broadly distributed crocodilian species, and thus is of special conservation and economic interest. Similar to other parts of its range throughout the Indo-Pacific, C. porosus distributed in the Republic of Palau have experienced a severe population decline over the past century primarily due to commercial hunting and eradication campaigns. In addition, several thousand crocodiles of undocumented species and origin were imported into Palau during the 1930’s for commercial farming purposes, potentially polluting the gene pool of the endemic saltwater crocodiles. Analysis of 39 individuals collected throughout the Republic of Palau revealed a single mitochondrial DNA control region haplotype shared by populations sampled in Sulawesi, Borneo and Australia. The mtDNA results, in combination with microsatellite genotypic data at six loci, detected no evidence for inter-specific hybridization between endemic Palauan C. porosus and potentially introduced Crocodylus species. There was no evidence for a genetic bottleneck in the Palauan population, however an excess of rare alleles was identified, indirectly suggesting a recent history of admixture potentially linked to introductions of non-native C. porosus. Following from these findings, Palauan C. porosus should be included in the single ESU previously established for all saltwater crocodiles given the recovery of a fixed, but geographically widespread haplotype. Although Palauan C. porosus exhibited significant genetic differentiation relative to all other sampled populations, it’s delineation as a distinct management unit is precluded at the present time by evidence that the genetic integrity of the population may have been compromised by the introduction of non-native saltwater crocodiles.
Keyword Saltwater crocodile
Microsatellite
Mitochondrial DNA control region
Population bottleneck
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Non-UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: Queensland Brain Institute Publications
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Created: Sat, 22 Oct 2011, 01:06:49 EST by Jake Gratten on behalf of Queensland Brain Institute