Microsatellite and mitochondrial DNA variation defines island genetic reservoirs for reintroductions of an endangered Australian marsupial, Perameles bougainville

Abstract

Natural populations of the endangered western barred bandicoot (Perameles bougainville) now exist on only two islands in Shark Bay, Western Australia. Our aim was to investigate genetic diversity in natural, reintroduced, and captive populations of the bandicoots and to assess the extent of divergence between the populations. The contemporary isolation of the natural populations has resulted in heterogeneity of allele frequency between the islands, which has acted to maintain a higher combined diversity than would be expected from either population on its own. These findings highlight how remnant island populations can act as genetic reservoirs to maximize diversity for reintroductions into a species former range. Although diversity is high between island populations, diversity within populations, based on six microsatellite loci, are amongst the lowest ever recorded for populations of marsupials. The mtDNA sequence data indicate that the two remaining natural populations show only minor divergence from each other, with the five haplotypes separated by just single base pairs. The reintroduced population and captive colonies show evidence for the loss of diversity related to genetic drift operating on small isolated populations.

Ex situ conservation genetics: a review of molecular studies on the genetic consequences of captive breeding programmes for endangered animal species

“…90% of the mean H e in wild populations). We only found one exception (Western barred bandicoot: Perameles bougainville), in which H e was low (0.27) despite the number of 30 founders (Smith and Hughes 2008). However, in this case the sampling of the captive population was rather low (N = 8) and H e was also low in the wild populations.…”

Prevalence, Emergence, and Factors Associated with a Viral Papillomatosis and Carcinomatosis Syndrome in Wild, Reintroduced, and Captive Western Barred Bandicoots (Perameles bougainville)

“…A recent study by Smith and Hughes (2007a) found genetic diversity levels in the WBB, estimated by genotyping six microsatellite loci across 134 individuals from 5 populations (Bernier and Dorre…”

“…Islands, Heirisson Prong, the PCBC and Dryandra), to be amongst the lowest ever recorded for a population of marsupials (Smith and Hughes 2007a). Reduced genetic diversity may increase susceptibility of a species to novel diseases, environmental stresses and, ultimately extinction (World Conservation Monitoring Centre 1992;Frankham 1997;Smith and Hughes 2007a).…”

“…Reduced genetic diversity may increase susceptibility of a species to novel diseases, environmental stresses and, ultimately extinction (World Conservation Monitoring Centre 1992;Frankham 1997;Smith and Hughes 2007a). An increased incidence of similar, papillomavirus-associated disease has also been reported in other endangered species (Joslin et al 2000;Bossart et al 2002;Tachezy et al 2002b).…”

“…(Frankham 1997). Smith and Hughes (2007a) found that the contemporary isolation of Bernier and Dorre Islands has acted to maintain a higher combined effective WBB population size than would be expected from either population on its own, and that future use of both genetic reservoirs would act to maximise genetic diversity for mainland reintroductions (Smith and Hughes 2007a Figure 3 Cummalative probability of remaining free of the papillomatosis and carcinomatosis syndrome with progressive age. The probability of remaining disease free decreased with age, indicating that the risk of developing this disease increased as the individual aged.…”