Eldridge Mark D B, Miller Emily J, Neaves Linda E, Zenger Kyall R, Herbert Catherine A
Australian Museum Research Institute, Sydney, New South Wales, Australia.
Department of Biological Sciences, Macquarie University, New South Wales, Australia.
PLoS One. 2017 Mar 3;12(3):e0172777. doi: 10.1371/journal.pone.0172777. eCollection 2017.
The tammar wallaby (Notamacropus eugenii) is one of the most intensively studied of all macropodids and was the first Australasian marsupial to have its genome sequenced. However, comparatively little is known about genetic diversity and differentiation amongst the morphologically distinct allopatric populations of tammar wallabies found in Western (WA) and South Australia (SA). Here we compare autosomal and Y-linked microsatellite genotypes, as well as sequence data (~600 bp) from the mitochondrial DNA (mtDNA) control region (CR) in tammar wallabies from across its distribution. Levels of diversity at autosomal microsatellite loci were typically high in the WA mainland and Kangaroo Island (SA) populations (A = 8.9-10.6; He = 0.77-0.78) but significantly reduced in other endemic island populations (A = 3.8-4.1; He = 0.41-0.48). Autosomal and Y-linked microsatellite loci revealed a pattern of significant differentiation amongst populations, especially between SA and WA. The Kangaroo Island and introduced New Zealand population showed limited differentiation. Multiple divergent mtDNA CR haplotypes were identified within both SA and WA populations. The CR haplotypes of tammar wallabies from SA and WA show reciprocal monophyly and are highly divergent (14.5%), with levels of sequence divergence more typical of different species. Within WA tammar wallabies, island populations each have unique clusters of highly related CR haplotypes and each is most closely related to different WA mainland haplotypes. Y-linked microsatellite haplotypes show a similar pattern of divergence although levels of diversity are lower. In light of these differences, we suggest that two subspecies of tammar wallaby be recognized; Notamacropus eugenii eugenii in SA and N. eugenii derbianus in WA. The extensive neutral genetic diversity and inter-population differentiation identified within tammar wallabies should further increase the species value and usefulness as a model organism.
帚尾袋鼩（Notamacropus eugenii）是所有袋鼠科动物中研究最为深入的物种之一，也是首个完成基因组测序的澳大利亚有袋类动物。然而，对于在西澳大利亚州（WA）和南澳大利亚州（SA）发现的形态各异的异域帚尾袋鼩种群之间的遗传多样性和分化情况，人们了解得相对较少。在此，我们比较了分布范围内的帚尾袋鼩常染色体和Y连锁微卫星基因型，以及线粒体DNA（mtDNA）控制区（CR）的序列数据（约600 bp）。常染色体微卫星位点的多样性水平在西澳大利亚州大陆和袋鼠岛（南澳大利亚州）种群中通常较高（等位基因数A = 8.9 - 10.6；期望杂合度He = 0.77 - 0.78），但在其他地方性岛屿种群中显著降低（A = 3.8 - 4.1；He = 0.41 - 0.48）。常染色体和Y连锁微卫星位点揭示了种群间显著的分化模式，尤其是在南澳大利亚州和西澳大利亚州之间。袋鼠岛和引入的新西兰种群显示出有限的分化。在南澳大利亚州和西澳大利亚州的种群中均鉴定出多个不同的线粒体DNA控制区单倍型。来自南澳大利亚州和西澳大利亚州的帚尾袋鼩的控制区单倍型呈现出相互单系性且高度分化（14.5%），序列分化水平更具不同物种的典型特征。在西澳大利亚州的帚尾袋鼩中，岛屿种群各自拥有高度相关的控制区单倍型独特聚类，且每个聚类与不同的西澳大利亚州大陆单倍型关系最为密切。Y连锁微卫星单倍型显示出类似的分化模式，尽管多样性水平较低。鉴于这些差异，我们建议认可帚尾袋鼩的两个亚种；南澳大利亚州的Notamacropus eugenii eugenii和西澳大利亚州的N. eugenii derbianus。在帚尾袋鼩中发现的广泛中性遗传多样性和种群间分化应进一步提升该物种作为模式生物的价值和实用性。
