Importance of dispersal routes that minimize open-ocean movement to the genetic structure of island populations.

Islands present a unique scenario in conservation biology, offering refuge yet imposing limitations on insular populations. The Kimberley region of northwestern Australia has more than 2500 islands that have recently come into focus as substantial conservation resources. It is therefore of great interest for managers to understand the driving forces of genetic structure of species within these island archipelagos. We used the ubiquitous bar-shouldered skink (Ctenotus inornatus) as a model species to represent the influence of landscape factors on genetic structure across the Kimberley islands. On 41 islands and 4 mainland locations in a remote area of Australia, we genotyped individuals across 18 nuclear (microsatellite) markers. Measures of genetic differentiation and diversity were used in two complementary analyses. We used circuit theory and Mantel tests to examine the influence of the landscape matrix on population connectivity and linear regression and model selection based on Akaike's information criterion to investigate landscape controls on genetic diversity. Genetic differentiation between islands was best predicted with circuit-theory models that accounted for the large difference in resistance to dispersal between land and ocean. In contrast, straight-line distances were unrelated to either resistance distances or genetic differentiation. Instead, connectivity was determined by island-hopping routes that allow organisms to minimize the distance of difficult ocean passages. Island populations of C. inornatus retained varying degrees of genetic diversity (NA = 1.83 - 7.39), but it was greatest on islands closer to the mainland, in terms of resistance-distance units. In contrast, genetic diversity was unrelated to island size. Our results highlight the potential for islands to contribute to both theoretical and applied conservation, provide strong evidence of the driving forces of population structure within undisturbed landscapes, and identify the islands most valuable for conservation based on their contributions to gene flow and genetic diversity.

Parentage testing of racing camels (Camelus dromedarius) using microsatellite DNA typing.

The camel racing industry would have added value in being able to assign parentage with high certainty. This study was aimed at assessing and applying microsatellite multiplexes to construct a parentage testing system for camels. An efficient system of 17 loci from 700 camel samples was used to construct a database of unrelated adults. Based on this, we estimated measures of polymorphism among the markers. In three multiplex reactions, we detected a total of 224 alleles, with 5­23 alleles/locus (mean = 13.18 ± 6.95 SD) and an average heterozygosity (HE) of 0.54 (range 0.032­0.905). The total parentage exclusion probability was 0.99999 for excluding a candidate parent from parentage of an arbitrary offspring, given only the genotype of the offspring, and 0.9999 for excluding a candidate parent from parentage of an arbitrary offspring, given the genotype of the offspring and the other parent. We used 15 juveniles for parentage testing, as well as 17 sires (bull camels) and 21 dams (cows). In the case of parentage assignment, the microsatellite panel assigned all 15 offspring parentage with high confidence. Overall, these findings offer a set of microsatellite markers that are easy, simple and highly informative for parentage testing in camels.

Identification of historical specimens and wildlife seizures originating from highly degraded sources of kangaroos and other macropods.

Forensic investigations are an important area in the regulation of food mis-description, wildlife seizures and the international trade in wildlife and its products. An early, but important stage in dealing with many biological materials that are submitted for forensic scrutiny is species identification. We describe a method and new primers to amplify three small DNA fragments of the cytochrome b region of the mitochondrial DNA that are suitable for marsupial species identification from degraded sources, such as wildlife seizures. They were designed as consensus sequences from a comparison of 21 marsupial species. The primers also contained sequences intended specifically not to amplify human DNA, thereby reducing the likelihood of amplifying contaminants. Examples of the utility of these primers are given using a range of conditions that may be applied using such an approach, including (1) field-collected sub-fossil bones, (2) an example of museum mis-identification from a specimen collected in 1930 and (3) a skull collected from Bernier Island, in the harsh mid-west of Western Australia.

Effects of temperature and duration of sample storage on the haematological characteristics of western grey kangaroos (Macropus fuliginosus).

OBJECTIVE: To investigate the effects of storage duration and temperature on haematological analyses performed on blood from the western grey kangaroo (Macropus fuliginosis). METHOD: Blood samples from five western grey kangaroos were stored at 4 degrees C, 24 degrees C and 36 degrees C. Each sample was analysed haematologically over a 5-day period. RESULTS: The blood samples maintained optimal stability at 4 degrees C. At this temperature the haematological values remained essentially unchanged for the duration of the study, while samples stored at 36 degrees C and 24 degrees C showed significant changes in some haematological measures by 12 h and 48 h, respectively. Disturbances in leukocyte morphology were evident, to varying degrees, in all samples. CONCLUSIONS: Blood samples from macropodids should be tested within 48 h of collection if stored at a room temperature of about 24 degrees C. Where testing is to be delayed for more than 48 h, samples should be refrigerated as soon as possible. Exposure of samples to heat in excess of 24 degrees C should be avoided at all times.

Morphological and molecular characteristics of a species of Hepatozoon Miller, 1908 (Apicomplexa: Adeleorina) from the blood of Isoodon obesulus (Marsupialia: Peramelidae) in Western Australia.

Examination of blood films as part of a study to assess the health status of the southern brown bandicoot Isoodon obesulus (Shaw) in Western Australia revealed the gamonts of a haemogregarine parasite in some samples, the first to be recognised in a bandicoot in this state. Light microscope morphological characteristics and partial sequence of the 18S rRNA gene were used to describe these organisms. Morphological characters did not differentiate the organism in the current study from previously reported Hepatozoon peramelis (Welsh & Dalyell, 1909). Phylogenetic analysis has not previously been reported for any species of Hepatozoon from Australian marsupials and consequently could not be used to confirm the identity of the organism in the current study as that described in the 1900s. If this organism is H. peramelis, then it has a wide distribution, being found in three species of bandicoot, in western and eastern Australia and the in island state of Tasmania.