Data from: Anthropogenic selection enhances cancer evolution in Tasmanian devil tumours

The Tasmanian Devil Facial Tumour Disease (DFTD) provides a unique opportunity to elucidate the long-term effects of natural and anthropogenic selection on cancer evolution. Since first observed in 1996, this transmissible cancer has caused local population declines by >90%. So far, four chromosomal DFTD variants (strains) have been described and karyotypic analyses of 253 tumours showed higher levels of tetraploidy in the oldest strain. We propose that increased ploidy in the oldest strain may have evolved in response to effects of genomic decay observed in asexually reproducing organisms. In this study, we focus on the evolutionary response of DFTD to a disease suppression trial. Tumours collected from devils subjected to the removal programme showed accelerated temporal evolution of tetraploidy compared with tumours from other populations where no increase in tetraploid tumours were observed. As ploidy significantly reduces tumour growth rate, we suggest that the disease suppression trial resulted in selection favouring slower growing tumours mediated by an increased level of tetraploidy. Our study reveals that DFTD has the capacity to rapidly respond to novel selective regimes and that disease eradication may result in novel tumour adaptations, which may further imperil the long-term survival of the world's largest carnivorous marsupial.

塔斯马尼亚恶魔面部肿瘤病（DFTD）为阐明自然选择与人为选择对癌症演化的长期影响提供了独特契机。自1996年首次被发现以来，这种可传播癌症已导致局部种群数量下降超90%。截至目前，学界已报道四种染色体型DFTD变异株（毒株）；对253份肿瘤样本的核型分析显示，最古老的毒株呈现更高水平的四倍体。我们提出假说：最古老毒株的倍性升高，可能是为适应无性繁殖生物中观察到的基因组衰退效应而演化而来。本研究聚焦DFTD对疾病抑制试验的演化响应。相较于未观测到四倍体肿瘤比例上升的其他种群来源的肿瘤，接受移除计划的袋獾所采集的肿瘤，其四倍体的时间演化速率显著更快。鉴于倍性可显著降低肿瘤生长速率，我们认为疾病抑制试验通过提升四倍体水平，筛选出了生长更缓慢的肿瘤株系。本研究表明，DFTD具备快速响应新型选择压力环境的能力，而疾病根除可能会催生新的肿瘤适应性变异，这或许会进一步威胁到这种全球最大食肉有袋类动物的长期生存。