Knies Jennifer L, Kingsolver Joel G, Burch Christina L
Department of Biology, University of North Carolina, Chapel Hill, NC 27599, USA.
Am Nat. 2009 Apr;173(4):419-30. doi: 10.1086/597224.
Hotter is better is a hypothesis of thermal adaptation that posits that the rate-depressing effects of low temperature on biochemical reactions cannot be overcome by physiological plasticity or genetic adaptation. If so, then genotypes or populations adapted to warmer temperatures will have higher maximum growth rates than those adapted to low temperatures. Here we test hotter is better by measuring thermal reaction norms for intrinsic rate of population growth among an intraspecific collection of bacteriophages recently isolated from nature. Consistent with hotter is better, we find that phage genotypes with higher optimal temperatures have higher maximum growth rates. Unexpectedly, we also found that hotter is broader, meaning that the phages with the highest optimal temperatures also have the greatest temperature ranges. We found that the temperature sensitivity of fitness for phages is similar to that for insects.
“越热越好”是一种热适应假说，该假说认为低温对生化反应的速率抑制作用无法通过生理可塑性或基因适应来克服。如果是这样，那么适应较温暖温度的基因型或种群将比适应低温的基因型或种群具有更高的最大生长速率。在这里，我们通过测量最近从自然界分离出的噬菌体种内集合中种群增长内在速率的热反应规范，来检验“越热越好”这一假说。与“越热越好”一致，我们发现具有较高最适温度的噬菌体基因型具有更高的最大生长速率。出乎意料的是，我们还发现“越热范围越广”，即最适温度最高的噬菌体也具有最大的温度范围。我们发现噬菌体适合度的温度敏感性与昆虫相似。
