Ahrens Collin W, Griffiths Josh, Danger Al, Coleman Rhys, van Rooyen Anthony, Furlan Elise, Weeks Andrew R
Cesar Australia, 95 Albert St, Brunswick, VIC, 3056, Australia.
Hawkesbury Institute for the Environment, Western Sydney University, Richmond, NSW, 2753, Australia.
Heredity (Edinb). 2025 Jun 6. doi: 10.1038/s41437-025-00774-w.
The platypus is an evolutionary unique mammal on the east coast of mainland Australia and throughout Tasmania. The species is dependent on freshwater ecosystems, is declining throughout its range, and is listed as Vulnerable in the state of Victoria, and Near Threatened on the IUCN Red List. This relatively long-lived species is cryptic and nocturnal making it difficult to study in natural populations. Relatively little is known about its demographic history or the forces that shape genetic variation. We use a unique genomic dataset comprising 2715 single-nucleotide polymorphisms from 545 individual platypuses sampled from five catchments across Melbourne, Victoria. This dataset enabled us to describe the genetic variation across the catchments and test hypotheses relating to migration, effective population size, and potential negative effects of anthropogenic barriers. We found relatively consistent levels of genetic diversity in platypuses across Melbourne's catchments, moderate levels of within-catchment migration, and genetic differentiation both between and within catchments. This genetic structure is explained by several factors, including isolation-by-river-distance, isolation-by-environment and within-catchment sex biased dispersal at short distances. These patterns are likely explained by a temporal lag between indirect and direct anthropogenic changes to the environmental and genetic variation, and these contemporary analyses likely reflect historical demographic patterns. In addition, we find that anthropogenic barriers such as dams have not measurably affected migration in these catchments. Our study highlights future evolutionary challenges that exist for platypuses in Melbourne's catchments, which could be representative of their entire range along the east coast of Australia.
鸭嘴兽是澳大利亚大陆东海岸及整个塔斯马尼亚岛一种在进化上独特的哺乳动物。该物种依赖淡水生态系统，其分布范围正在缩减，在维多利亚州被列为易危物种，在国际自然保护联盟红色名录中被列为近危物种。这种寿命相对较长的物种隐秘且夜行，使得在自然种群中对其进行研究很困难。人们对其种群历史或塑造遗传变异的因素了解相对较少。我们使用了一个独特的基因组数据集，该数据集包含从维多利亚州墨尔本的五个集水区采集的545只鸭嘴兽的2715个单核苷酸多态性。这个数据集使我们能够描述集水区内的遗传变异，并检验与迁移、有效种群大小以及人为屏障潜在负面影响相关的假设。我们发现墨尔本各集水区的鸭嘴兽遗传多样性水平相对一致，集水区内迁移水平适中，集水区之间以及集水区内部都存在遗传分化。这种遗传结构由多种因素解释，包括河流距离隔离、环境隔离以及集水区内短距离的性别偏向扩散。这些模式可能是由环境和遗传变异的间接和直接人为变化之间的时间滞后所解释的，而这些当代分析可能反映了历史种群模式。此外，我们发现水坝等人为屏障并未对这些集水区的迁移产生可测量的影响。我们的研究突出了墨尔本集水区鸭嘴兽未来面临的进化挑战，这些挑战可能代表了它们在澳大利亚东海岸整个分布范围内所面临的情况。
