Disentangling the Relationship of the Australian Marsupial Orders Using Retrotransposon and Evolutionary Network Analyses
Disentangling the Relationship of the Australian Marsupial Orders Using Retrotransposon and Evolutionary Network Analyses
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DOI：
10.1093/gbe/evv052
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发表时间：
2015-04-01
影响因子：
3.3
通讯作者：
Nilsson, Maria A.
中科院分区：
文献类型：
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作者：
Gallus, Susanne;Janke, Axel;Nilsson, Maria A.
澳大利亚有袋类动物的祖先大约在60(54-72)Ma左右从南极洲进入澳大利亚，并辐射成四个生活目：双齿动物、双齿动物、双齿动物和无齿动物。澳大利亚四个有袋动物目之间的关系一直是一个长期存在的问题，因为不同的系统发育研究一直无法一致地重建相同的拓扑结构。在对塔斯马尼亚魔鬼基因组的初步电子分析和对七个有袋类目的实验筛选中，发现了20个信息丰富的转座元件插入，以解决澳大利亚和南美洲目的序间和序内关系。然而，反转录转座子插入支持三种相互冲突的拓扑结构，即全色形态症、双形态型和Notoryctemogia，这表明这三个目之间的分裂可能最好被理解为一个网络。这一发现得到了对核基因序列的系统发育重新分析的支持，该分析使用了一种共识网络方法，允许描绘隐藏的系统发育冲突，否则当迫使数据进入分叉树时就会丢失。共识网络分析与转座元件分析一致，因为在有根的四分类体拓扑中，关于全裂形体、Dasyurophia和Notoryctemomia的所有可能的拓扑结构都同样得到很好的支持。此外，反转录转座子插入数据支持南美双生异形目是所有其他有袋类目的姊妹群。这四个澳大利亚目起源于白垩纪-古近纪界线的3Myr以内。这种快速的分化在基因组中留下了相互矛盾的系统发育信息，可能是由于不完全的谱系排序或渐进式杂交产生的，这使得澳大利亚有袋类目之间的关系在数百万年后作为一个分裂的过程无法解决。
The ancestors to the Australian marsupials entered Australia around 60 (54-72) Ma from Antarctica, and radiated into the four living orders Peramelemorphia, Dasyuromorphia, Diprotodontia, and Notoryctemorphia. The relationship between the four Australian marsupial orders has been a long-standing question, because different phylogenetic studies have not been able to consistently reconstruct the same topology. Initial in silico analysis of the Tasmanian devil genome and experimental screening in the seven marsupial orders revealed 20 informative transposable element insertions for resolving the inter- and intraordinal relationships of Australian and South American orders. However, the retrotransposon insertions support three conflicting topologies regarding Peramelemorphia, Dasyuromorphia, and Notoryctemorphia, indicating that the split between the three orders may be best understood as a network. This finding is supported by a phylogenetic reanalysis of nuclear gene sequences, using a consensus network approach that allows depicting hidden phylogenetic conflict, otherwise lost when forcing the data into a bifurcating tree. The consensus network analysis agrees with the transposable element analysis in that all possible topologies regarding Peramelemorphia, Dasyuromorphia, and Notoryctemorphia in a rooted four-taxon topology are equally well supported. In addition, retrotransposon insertion data support the South American order Didelphimorphia being the sistergroup to all other living marsupial orders. The four Australian orders originated within 3 Myr at the Cretaceous-Paleogene boundary. The rapid divergences left conflicting phylogenetic information in the genome possibly generated by incomplete lineage sorting or introgressive hybridization, leaving the relationship among Australian marsupial orders unresolvable as a bifurcating process millions of years later.