Bargas-Galarraga Iker, Vilà Carles, Gonzalez-Voyer Alejandro
Am Nat. 2023 Feb;201(2):163-174. doi: 10.1086/722531. Epub 2022 Dec 15.
AbstractProminent differences in aging among and within species present an evolutionary puzzle. The theories proposed to explain evolutionary differences in aging are based on the axiom that selection maximizes fitness, not necessarily life span. This implies trade-offs between investment in self-maintenance and investment in reproduction, where high investments in growth and current reproduction are associated with short life spans. Fast growth and large adult size are related to shorter life spans in the domestic dog, a bourgeoning model in aging research; however, whether reproduction influences life span in this system remains unknown. Here we test the relationship between reproduction and differences in life span among dog breeds, simultaneously controlling for shared ancestry and recent gene flow. We found that shared ancestry explains a higher proportion of the among-breed variation in life history traits, in comparison with recent gene flow. Our results also show that reproductive investment negatively impacts life span, and more strongly so in large breeds, an effect that is not merely a correlated response of adult size. These results suggest that basic life history trade-offs are apparent in a domestic animal whose diversity is the result of artificial selection and that among-breed differences in life span are due to a combination of size and reproduction.
物种之间和物种内部衰老的显著差异构成了一个进化难题。为解释衰老进化差异而提出的理论基于这样一个公理，即选择使适应性最大化，而不一定是寿命最大化。这意味着在自我维持投资和繁殖投资之间存在权衡，在生长和当前繁殖方面的高投资与较短的寿命相关。在衰老研究中新兴的模型——家犬中，快速生长和成年体型较大与较短的寿命有关；然而，在这个系统中繁殖是否影响寿命仍然未知。在这里，我们测试了繁殖与犬种之间寿命差异的关系，同时控制了共同祖先和近期基因流动的影响。我们发现，与近期基因流动相比，共同祖先在家犬品种间生活史特征变异中所占比例更高。我们的研究结果还表明，繁殖投资对寿命有负面影响，在大型犬种中这种影响更强，而且这种影响不仅仅是成年体型的相关反应。这些结果表明，基本的生活史权衡在一个多样性是人工选择结果的家养动物中很明显，而且犬种间的寿命差异是体型和繁殖共同作用的结果。
