Osozawa Soichi, Nel André
Institute of Geology and Paleontology, Faculty of Science Tohoku University Sendai Japan.
Present address: KawaOso Molecular Bio-Geology Institute Sendai Japan.
Ecol Evol. 2024 Sep 18;14(9):e70297. doi: 10.1002/ece3.70297. eCollection 2024 Sep.
Applying BEAST v1.10.4, we constructed a Bayesian Inference tree comprising 322 taxa, primarily representing Paleoptera (Odonata and Ephemeroptera; Pterygota), Zygentoma and Archaeognatha (Apterygota; paraphyly), and Neoptera (Plecoptera; Pterygota), based on a 2685 bp sequence dataset. Our analyses revealed that robust dating required the incorporation of both Quaternary and pre-Quaternary dates. To achieve this, our dating incorporated a 1.55 Ma (Quaternary) geological event (the formation of the Ryukyu Islands) and a set of chronologically well-founded fossil dates, spanning from up to 400 Ma (Devonian) for the stem Archaeognatha, 320 Ma (Carboniferous) for the crown of Paleoptera, 300 Ma (Carboniferous) for the crown Ephemeroptera, and 280 Ma (Permian) for the crown Odonata, down to 1.76 Ma (Quaternary) for , encompassing a total of 22 calibration points (events: 6, fossils: 16; Quaternary: 7, pre-Quaternary: 15). The resulting dated tree aligns with previous research, albeit with some dates being overestimated. This overestimation was mainly due to the lack of Quaternary calibration and the exclusive dependence on pre-Quaternary calibration, though the application of maximum age constraints also played a role. Our minimum age dating demonstrates that the molecular clock did not uniformly progress, rendering rate dating an inapplicable approach. We observed that the base substitution rate is time-dependent, with an exponential increase evident from around 20 Ma (Miocene) to the present time, exceeding an order of magnitude. The extensive radiation and speciation of Insecta and Paleoptera, potentially resulting from the severe climatic changes associated with the Quaternary, including the commencement of glacial and interglacial cycles, may have significantly contributed to this increase in base substitution rates. Additionally, we identified a potential peak in base substitution rates during the Carboniferous period, around 320 million years ago, possibly corresponding to the Late Paleozoic Ice Age.
应用BEAST v1.10.4，我们基于一个2685bp的序列数据集构建了一棵贝叶斯推断树，该树包含322个分类单元，主要代表古翅类（蜻蜓目和蜉蝣目；有翅亚纲）、衣鱼目和石蛃目（无翅亚纲；并系群）以及新翅类（襀翅目；有翅亚纲）。我们的分析表明，可靠的定年需要纳入第四纪和第四纪之前的年代数据。为实现这一点，我们的定年纳入了一个155万年（第四纪）的地质事件（琉球群岛的形成）以及一组年代顺序明确的化石年代，时间跨度从石蛃目干群的4亿年（泥盆纪）、古翅类冠群的3.2亿年（石炭纪）、蜉蝣目冠群的3亿年（石炭纪）、蜻蜓目冠群的2.8亿年（二叠纪），到[此处原文缺失相关分类单元名称]的176万年（第四纪），总共包括22个校准点（事件：6个，化石：16个；第四纪：7个，第四纪之前：15个）。所得的定年树与先前的研究结果一致，但有些年代被高估了。这种高估主要是由于缺乏第四纪校准且完全依赖第四纪之前的校准，不过最大年龄限制的应用也起到了一定作用。我们的最小年龄定年表明分子钟并非匀速运行，这使得速率定年成为一种不适用的方法。我们观察到碱基替换率与时间相关，从大约200万年（中新世）到现在呈指数增长，超过了一个数量级。昆虫纲和古翅类的广泛辐射和物种形成，可能是由与第四纪相关的剧烈气候变化导致的，包括冰川期和间冰期循环的开始，这可能显著促成了碱基替换率的这种增加。此外，我们确定在大约3.2亿年前的石炭纪时期碱基替换率可能存在一个峰值，这可能与晚古生代冰期相对应。
