逆转录病毒是一个古老的病毒家族，在全球范围内与脊椎动物共同进化并影响了它们的进化。在澳大利亚这个地理上与世隔绝了数百万年的大陆，尽管逆转录病毒对濒临灭绝的考拉种群造成了毁灭性影响，但人们对野生动物中的逆转录病毒知之甚少。因此，我们试图通过从有袋动物基因组中重建内源性逆转录病毒（ERV）来识别和表征澳大利亚逆转录病毒，特别是塔斯马尼亚袋獾，因为其高癌症发病率。我们筛选了 19 个有袋动物基因组，鉴定了超过 80,000 个 ERV 片段，并将其分为 8 个逆转录病毒分支。这些逆转录病毒与 Betaretrovirus (5/8) 或 Gammaretrovirus (3/8) 逆转录病毒相似，但与现有逆转录病毒相比形成了不同的系统发育分支。其中一个进化枝 (MEBrv 3) 失去了包膜，但保留了逆转录转座活性，随后在所有 Dasyuridae 基因组中扩增。总体而言，我们深入了解了澳大利亚逆转录病毒的进化，并鉴定了 Dasyuridae 基因组中高度活跃的 ERV。© 作者 2024。由牛津大学出版社代表分子生物学与进化学会出版。

Retroviruses are an ancient viral family that have globally coevolved with vertebrates and impacted their evolution. In Australia, a continent that has been geographically isolated for millions of years, little is known about retroviruses in wildlife, despite the devastating impacts of a retrovirus on endangered koala populations. We therefore sought to identify and characterise Australian retroviruses through reconstruction of endogenous retroviruses (ERVs) from marsupial genomes, in particular the Tasmanian devil due to its high cancer incidence. We screened 19 marsupial genomes and identified over 80,000 ERV fragments which we classified into eight retrovirus clades. The retroviruses were similar to either Betaretrovirus (5/8) or Gammaretrovirus (3/8) retroviruses, but formed distinct phylogenetic clades compared to extant retroviruses. One of the clades (MEBrv 3) lost an envelope but retained retrotranspositional activity, subsequently amplifying throughout all Dasyuridae genomes. Overall, we provide insights into Australian retrovirus evolution and identify a highly active ERV within Dasyuridae genomes.© The Author(s) 2024. Published by Oxford University Press on behalf of Society for Molecular Biology and Evolution.