Department of Anatomy, University of Otago, Dunedin, New Zealand.
Faculty of Environmental Earth Science, Hokkaido University, Sapporo, Hokkaido, 060-0808, Japan.
Nat Commun. 2023 Oct 17;14(1):6364. doi: 10.1038/s41467-023-41784-8.
Combining genome assembly with population and functional genomics can provide valuable insights to development and evolution, as well as tools for species management. Here, we present a chromosome-level genome assembly of the common brushtail possum (Trichosurus vulpecula), a model marsupial threatened in parts of their native range in Australia, but also a major introduced pest in New Zealand. Functional genomics reveals post-natal activation of chemosensory and metabolic genes, reflecting unique adaptations to altricial birth and delayed weaning, a hallmark of marsupial development. Nuclear and mitochondrial analyses trace New Zealand possums to distinct Australian subspecies, which have subsequently hybridised. This admixture allowed phasing of parental alleles genome-wide, ultimately revealing at least four genes with imprinted, parent-specific expression not yet detected in other species (MLH1, EPM2AIP1, UBP1 and GPX7). We find that reprogramming of possum germline imprints, and the wider epigenome, is similar to eutherian mammals except onset occurs after birth. Together, this work is useful for genetic-based control and conservation of possums, and contributes to understanding of the evolution of novel mammalian epigenetic traits.
将基因组组装与群体和功能基因组学相结合，可以为物种的发展和进化提供有价值的见解，以及物种管理的工具。在这里，我们呈现了一种常见帚尾袋貂（Trichosurus vulpecula）的染色体水平基因组组装，帚尾袋貂是一种有袋类模型动物，在其原生分布区的部分地区受到威胁，但也是新西兰的主要引入害虫。功能基因组学揭示了化学感觉和代谢基因的产后激活，反映了对早产儿出生和延迟断奶的独特适应，这是有袋类动物发育的标志。核和线粒体分析追踪到新西兰袋貂来自澳大利亚不同的亚种，随后这些亚种发生了杂交。这种杂种形成允许对全基因组的亲本等位基因进行相位划分，最终揭示了至少四个具有印记、亲本特异性表达的基因，这些基因尚未在其他物种中检测到（MLH1、EPM2AIP1、UBP1 和 GPX7）。我们发现，袋貂生殖系印记和更广泛的表观基因组的重编程与真兽类哺乳动物相似，但发生在出生后。总的来说，这项工作对于基于遗传的袋貂控制和保护很有用，并有助于理解新型哺乳动物表观遗传特征的进化。
