Abstract：
The Australian lungfish is a primitive and endangered representative of the subclass Dipnoi. The distribution of this species is limited to south-east Queensland, with some populations considered endemic and others possibly descending from translocations in the late nineteenth century shortly after European discovery. Attempts to resolve the historical distribution of this species have met with conflicting results based on descriptive genetic studies. Understanding if all populations are endemic or some are the result of, or influenced by, translocation events, has implications for conservation management. In this work, we analysed the genetic variation at three types of markers (mtDNA genomes, 11 STRs and 5196 nuclear SNPs) using the approximate Bayesian computation (ABC) algorithm to compare several demographic models. We postulated different contributions of Mary River and Burnett River gene pools into the Brisbane River and North Pine River populations, related to documented translocation events. We ran the analysis for each marker type separately, and we also estimated the posterior probabilities of the models combining the markers. Nuclear SNPs have the highest power to correctly identify the true model among the simulated datasets (where the model was known), but different marker types typically provided similar answers. The most supported demographic model able to explain the real dataset implies that an endemic gene pool is still present in the Brisbane and North Pine Rivers and coexists with the gene pools derived from past documented translocation events. These results support the view that ABC modelling can be useful to reconstruct complex historical translocation events with contemporary implications, and will inform ongoing conservation efforts for the endangered and iconic Australian lungfish.
摘要：
澳大利亚肺鱼是Dipnoi亚类的原始和濒危代表。该物种的分布仅限于昆士兰州东南部，一些人口被认为是地方性的，另一些人口可能是在19世纪后期欧洲发现后不久从易位下降的。基于描述性遗传研究，试图解决该物种的历史分布问题的结果相互矛盾。了解如果所有人口都是地方性的，或者一些是由以下因素导致的，或受影响，易位事件，对保护管理有影响。在这项工作中,我们分析了三种类型标记的遗传变异(mtDNA基因组，11个STR和5196个核SNP）使用近似贝叶斯计算（ABC）算法比较几种人口统计学模型。我们假设玛丽河和伯内特河基因库对布里斯班河和北松河种群的贡献不同，与记录的易位事件有关。我们分别对每种标记进行了分析，我们还估计了结合标记的模型的后验概率。核SNP具有在模拟数据集（已知模型的位置）中正确识别真实模型的最高能力，但不同的标记类型通常提供类似的答案。能够解释真实数据集的最受支持的人口统计学模型意味着，布里斯班和北松河中仍然存在地方性基因库，并且与过去记录的易位事件衍生的基因库共存。这些结果支持以下观点：ABC建模可用于重建具有当代含义的复杂历史易位事件，并将为正在进行的濒危和标志性澳大利亚肺鱼的保护工作提供信息。
