Loehr John, Sundell Janne, Immonen Mikko, Väinölä Risto
Faculty of Biological and Environmental Sciences, Lammi Biological Station University of Helsinki Lammi Finland.
Faculty of Biological and Environmental Sciences University of Helsinki Helsinki Finland.
Ecol Evol. 2023 Aug 29;13(8):e10423. doi: 10.1002/ece3.10423. eCollection 2023 Aug.
Organisms colonizing new habitats can undergo adaptive change due to novel selective landscapes encountered in the new environment. Examples in nature where the development of the same traits has repeatedly occurred on multiple independent occasions upon colonizing a novel habitat represent instances of parallel evolution. Here we test whether the colonization of spring habitat by the principally lacustrine amphipod crustacean has resulted in parallel evolution in armature traits using empirical data on morphology and mitochondrial DNA and through a breeding experiment. Analysis of mtDNA CO1 sequences shows that the spring populations share no common history and have evolved in isolation from each other and from their neighbouring lake populations since deglaciation approximately 12,000 years ago and are now fixed for different haplogroups. Dorsal spines and lateral projections were absent or less developed in all spring populations than in lake populations. Variation in armature development also could be explained by predator presence as populations with fish predators exhibited more developed spines than those without fish. In a laboratory breeding experiment, hybrid Spring × Lake F1 offspring had intermediate development of armature compared to offspring of Lake × Lake and Spring × Spring matings. The results support the hypothesis that armature reduction has independently evolved on multiple occasions in . Recent research has questioned the degree to which parallel evolution actually explains variance in traits. Taking into account the predation regime, sexual dimorphism and mineral composition of the trait, a more precise understanding of the factors influencing parallel evolution emerges.
定殖于新栖息地的生物可能会因新环境中遇到的新选择格局而发生适应性变化。在自然界中，同一性状的发育在定殖到新栖息地后多次独立出现的例子代表了平行进化的实例。在此，我们利用形态学和线粒体DNA的实证数据，并通过一项育种实验，来测试主要生活在湖泊中的双甲目甲壳动物对春季栖息地的定殖是否导致了其铠甲性状的平行进化。对线粒体DNA细胞色素氧化酶亚基1（CO1）序列的分析表明，自约12000年前冰川消退以来，春季种群没有共同的历史，它们彼此之间以及与相邻湖泊种群相互隔离进化，现在固定为不同的单倍群。与湖泊种群相比，所有春季种群的背刺和侧突都不存在或发育较差。铠甲发育的差异也可以用捕食者的存在来解释，因为有鱼类捕食者的种群比没有鱼类的种群背刺发育更完善。在一项实验室育种实验中，春季×湖泊的杂交F1代后代与湖泊×湖泊和春季×春季交配的后代相比，铠甲发育处于中间水平。这些结果支持了铠甲减少在多个场合独立进化的假说。最近的研究对平行进化实际解释性状差异的程度提出了质疑。考虑到捕食方式、性别二态性和性状的矿物质组成，对影响平行进化的因素有了更精确的理解。
