Tian Xiangyu, Guo Jia, Song Yu, Yu Qunfei, Liu Chao, Fu Zhixi, Shi Yuhua, Shao Yizhen, Yuan Zhiliang
College of Life Sciences Henan Agricultural University Zhengzhou Henan China.
School of Life Sciences Zhengzhou University Zhengzhou Henan China.
Ecol Evol. 2024 Mar 11;14(3):e11119. doi: 10.1002/ece3.11119. eCollection 2024 Mar.
Blume is the northernmost tree species in the family Lauraceae, and it is a key species in understanding the evolutionary history of this family. The species of in East Asia has diverged into the Northern and Southern populations, which are geographically separated by an arid belt. Though the morphological differences between populations have been observed and well documented, intraspecific variations at the plastomic level have not been systematically investigated to date. Here, ten chloroplast genomes of individuals were sequenced and analyzed along with three publicly available plastomes. Comparative plastomic analysis suggests that both the Northern and the Southern populations share similar overall structure, gene order, and GC content in their plastomes although the size of the plasome and the level of intraspecific variability do vary between the two populations. The Northern have relatively larger plastomes while the Southern population possesses higher intraspecific variability, which could be attributed to the complexity of the geological environments in the South. Phylogenomic analyses also support the split of the Northern and Southern clades among individuals. However, there is no obvious species boundary between var. and var. in the Southern population, indicating that gene flow could still occur between these two varieties, and this could be used as a good example of reticulate evolution. It is also found that a few photosynthesis-related genes are under positive selection, which is mainly related to the geological and environmental differences between the Northern and the Southern regions. Our results provide a reference for phylogenetic analysis within species and suggest that phylogenomic analyses with a sufficient number of nuclear and chloroplast genomic target loci from widely distributed individuals could provide a deeper understanding of the population evolution of the widespread species.
樟科是北半球最北的树种，也是理解该科进化历史的关键物种。东亚的该物种已分化为北方种群和南方种群，它们在地理上被一条干旱带隔开。尽管已观察到种群之间的形态差异并进行了详细记录，但迄今为止尚未对叶绿体基因组水平的种内变异进行系统研究。在此，对10个个体的叶绿体基因组进行了测序和分析，并结合了三个公开可用的叶绿体基因组。比较叶绿体基因组分析表明，北方种群和南方种群的叶绿体基因组在整体结构、基因顺序和GC含量方面相似，尽管两个种群的叶绿体基因组大小和种内变异水平有所不同。北方种群的叶绿体基因组相对较大，而南方种群的种内变异较高，这可能归因于南方地质环境的复杂性。系统发育基因组分析也支持在这些个体中北方和南方分支的分裂。然而，南方种群的[具体变种1]和[具体变种2]之间没有明显的物种界限，这表明这两个变种之间仍可能发生基因流动，这可以作为网状进化的一个很好的例子。还发现一些与光合作用相关的基因受到正选择，这主要与北方和南方地区的地质和环境差异有关。我们的结果为物种内的系统发育分析提供了参考，并表明对广泛分布个体的足够数量的核和叶绿体基因组目标位点进行系统发育基因组分析可以更深入地了解广泛分布物种的种群进化。
