塔斯马尼亚恶魔面对可传染癌症的适应潜力

Adaptive potential in the face of a transmissible cancer in Tasmanian devils

MOLECULAR ECOLOGY

影响因子:3.9

分区:生物学1区 Top / 生态学1区生化与分子生物学2区进化生物学2区

发表日期:2024 Nov

作者: Kasha Strickland, Menna E Jones, Andrew Storfer, Rodrigo K Hamede, Paul A Hohenlohe, Mark J Margres, Hamish I McCallum, Sebastien Comte, Shelly Lachish, Loeske E B Kruuk

DOI: 10.1111/mec.17531

摘要

新兴传染病（EID）不仅导致野生动物群体的灾难性下降，还产生选择压力，可能引发快速的进化反应。其中一种EID是塔斯马尼亚恶魔的魔鬼面部肿瘤病（DFTD）。DFTD几乎总是致命，已将个体的平均寿命缩短约2年，可能强烈选择减少易感性的性状，但人口下降也使塔斯马尼亚恶魔易受近亲繁殖抑制的影响。我们分析了来自塔斯马尼亚Freycinet半岛一项持续研究的22年数据，旨在：(1) 通过估算DFTD与体型性状的表型和遗传相关性，识别DFTD是否可能引起对体型的选择；(2) 估算对DFTD的易感性之加性遗传变异；(3) 探讨体型性状或对DFTD的易感性是否受到近交抑制。发现头宽与DFTD易感性之间存在正向表型关系，但未表现出遗传相关性。相反，体重与DFTD易感性之间存在负向表型关系，并有证据显示两者之间存在负向遗传相关性。对DFTD易感性、头宽和体重都存在加性遗传变异，但在任何这些性状中都未发现近交抑制的证据。这些结果表明，塔斯马尼亚恶魔具有对DFTD进行适应性反应的潜力，尽管实际的进化响应将关键取决于DFTD本身的演化。

Abstract

Emerging infectious diseases (EIDs) not only cause catastrophic declines in wildlife populations but also generate selective pressures that may result in rapid evolutionary responses. One such EID is devil facial tumour disease (DFTD) in the Tasmanian devil. DFTD is almost always fatal and has reduced the average lifespan of individuals by around 2 years, likely causing strong selection for traits that reduce susceptibility to the disease, but population decline has also left Tasmanian devils vulnerable to inbreeding depression. We analysed 22 years of data from an ongoing study of a population of Tasmanian devils on Freycinet Peninsula, Tasmania, to (1) identify whether DFTD may be causing selection on body size, by estimating phenotypic and genetic correlations between DFTD and size traits, (2) estimate the additive genetic variance of susceptibility to DFTD, and (3) investigate whether size traits or susceptibility to DFTD were under inbreeding depression. We found a positive phenotypic relationship between head width and susceptibility to DFTD, but this was not underpinned by a genetic correlation. Conversely, we found a negative phenotypic relationship between body weight and susceptibility to DFTD, and there was evidence for a negative genetic correlation between susceptibility to DFTD and body weight. There was additive genetic variance in susceptibility to DFTD, head width and body weight, but there was no evidence for inbreeding depression in any of these traits. These results suggest that Tasmanian devils have the potential to respond adaptively to DFTD, although the realised evolutionary response will critically further depend on the evolution of DFTD itself.