Project description:The brushtail possum, Trichosurus vulpecula, is threatened in parts of its native range in Australia, but has also become a devastating mammalian pest following introduction into New Zealand from the mid 1800s. We have completed the first chromosome-level assembly of the possum genome and, using nuclear and mitochondrial analyses, traced southern New Zealand possums to distinct Tasmanian and mainland Australian subspecies, which have subsequently hybridised. This admixture is reflected in high levels of genetic diversity within New Zealand populations despite a founding bottleneck. Functional genomics revealed unique adaptations to altricial birth and extending weaning, including novel chemo-sensory genes, and at least four genes with imprinted, parent-specific expression not yet detected in other species (MLH1, EPM2AIP1, UBP1 and GPX7). We found that reprogramming of possum germline imprints and the wider epigenome was similar to eutherian mammals, except onset occurs after birth. Together, our data and analysis is useful for genetic-based control and conservation of possums, and contributes to understanding of the evolution of novel mammalian epigenetic traits such as germline methylation erasure and genomic imprinting.
Project description:The brushtail possum, Trichosurus vulpecula, is threatened in parts of its native range in Australia, but has also become a devastating mammalian pest following introduction into New Zealand from the mid 1800s. We have completed the first chromosome-level assembly of the possum genome and, using nuclear and mitochondrial analyses, traced southern New Zealand possums to distinct Tasmanian and mainland Australian subspecies, which have subsequently hybridised. This admixture is reflected in high levels of genetic diversity within New Zealand populations despite a founding bottleneck. Functional genomics revealed unique adaptations to altricial birth and extending weaning, including novel chemo-sensory genes, and at least four genes with imprinted, parent-specific expression not yet detected in other species (MLH1, EPM2AIP1, UBP1 and GPX7). We found that reprogramming of possum germline imprints and the wider epigenome was similar to eutherian mammals, except onset occurs after birth. Together, our data and analysis is useful for genetic-based control and conservation of possums, and contributes to understanding of the evolution of novel mammalian epigenetic traits such as germline methylation erasure and genomic imprinting.
