Barson Nicola J, Haugen Thrond O, Vøllestad L Asbjørn, Primmer Craig R
Centre for Ecological and Evolutionary Synthesis, University of Oslo, P.O. Box 1066 Blindern, N-0316 Oslo, Norway
Evolution. 2009 Feb;63(2):549-56. doi: 10.1111/j.1558-5646.2008.00554.x.
The development of isolation by distance (IBD) and isolation by time (IBT) was contrasted among demes of European grayling (Thymallus thymallus) that have diverged within the last 25 generations following colonization of a lake (Lesjaskogsvatnet). We find low but significant levels of genetic differentiation among spawning tributaries and a pattern of IBD among them. We do not, however, find evidence for IBT despite an up to four-week difference in spawning date between "warm/early" and "cold/late" spawning demes and differences in the incubation temperatures experienced by offspring. It appears that IBD has developed more rapidly than IBT in this system and that adaptive divergence has been initiated in the absence of IBT. Although analysis of selected loci could reveal reduced recombination in parts of the genome associated with temporal divergence, our analysis of neutral genetic data suggests that IBD is a more important isolating mechanism in the early stages of adaptive divergence in European grayling.
在欧洲茴鱼（Thymallus thymallus）的不同种群中，对比了距离隔离（IBD）和时间隔离（IBT）的发展情况。这些种群是在一个湖泊（Lesjaskogsvatnet）被殖民后的过去25代内分化形成的。我们发现产卵支流之间的遗传分化水平较低但显著，并且它们之间存在距离隔离模式。然而，尽管“温暖/早期”和“寒冷/晚期”产卵种群的产卵日期相差长达四周，且后代经历的孵化温度也有所不同，但我们并未找到时间隔离的证据。在这个系统中，距离隔离似乎比时间隔离发展得更快，并且在没有时间隔离的情况下已经开始了适应性分化。虽然对选定基因座的分析可能会揭示与时间差异相关的基因组部分重组减少，但我们对中性遗传数据的分析表明，在欧洲茴鱼适应性分化的早期阶段，距离隔离是一种更重要的隔离机制。
