Evolutionary principles and the genomic basis of convergent evolution of traits and characters in the Arabideae.

一般来说，生命，特别是植物，在进化的时间尺度上适应新的环境。如果我们的目标是理解生命如何在不断变化的环境中生存，那么研究适应是必不可少的，这是一个与当今世界直接相关的话题。对适应的研究往往受到缺乏复制的限制，如果没有独立的复制，就不可能确定我们在自然界中看到的东西中有多少是特定于某个实例的，有多少可以被视为一般结果或规则。然而，趋同进化允许我们克服这一根本限制，因为这个过程是自然界自己在产生表型方面的复制实验。这往往会导致趋同进化。趋同进化描述了同一表型在不同进化谱系中的独立发育。自达尔文时代以来，对趋同现象的观察就已经让人类着迷，但仍然令人费解的是，大自然如何能够为远亲物种的问题发明同样的解决方案。最直观的趋同进化是适应相似条件的结果。然而，它也可能是限制的结果，例如发育或突变。此外，渐渗也可以被认为是收敛的来源，这一概念在研究多倍化、网状进化和杂交普遍存在的植物的收敛进化时特别有趣。研究趋同进化需要大量的自然复制，即发现多个姐妹谱系在要分析的特征上不同的类群。在十字花科中，Arabideae部落是最突出的部落之一，它恰恰显示了这一必要的特征。它是一个单系组合，约有500种，分布在18个公认的属中，在所有主要谱系中都发现了特征和特征复合体的趋同。在我们的项目中，我们正在使用比较基因组学方法来寻找植物形态空间平行进化的基因组足迹，解释汇聚的表型和选定的复杂性状。人们经常看到，一些特征和特征结合在一起，甚至表现出趋同为一种综合征。这里我们关注最极端的特征之一，即单果(一年生)和多果(多年生)生活史的进化，这在十字花科中已经独立进化了许多次。时空环境证据将从关于分布范围和偏离时间估计的数据中间接收集。我们试图深化我们对十字花科进化原理的洞察，以便更好地理解一个以最高速度多样化的大型植物家族的成功进化史。

Life in general, and plants in particular, adapt to a new environment on evolutionary time scales. Studying adaptation is essential if we aim at understanding how life persists in the face of changing environments, a topic of immediate relevance in today’s world. The study of adaptation is often limited by a lack of replication and without independent replication it is impossible to determine how much of what we see in nature is particular to a certain example and how much can be regarded as a general result or rule. However, convergent evolution allows us to overcome this fundamental limitation, as this process is nature’s own replicate experiment in generating a phenotype. This leads very often to convergent evolution. Convergent evolution describes the independent development of the same phenotype in different evolutionary lineages. The observation of convergence has fascinated humans since Darwinian times already and it is still puzzling how nature is being able to invent the same solution for a problem in distantly related species. Most intuitively convergent evolution is the result of adaptation to similar conditions. However, it can also be the result of constraint, e.g. developmental or mutational. Furthermore, introgression can also be considered as a source for convergence, a notion which is of particular interest when studying convergent evolution in plants where polyploidization, reticulate evolution and hybridization are a common phenomenon. Studying convergent evolution requires the availability of a large number of natural replicates, i.e. groups of taxa where multiple sister lineages are found that differ in the traits to be analysed. Within the Brassicaceae family the tribe Arabideae is one of the most prominent tribes and it displays exactly this required feature. It is a monophyletic assemblage with roughly 500 species distributed among 18 accepted genera where convergence of traits and trait complexes is found in all main lineages. With our project we are using comparative genomic approaches to seek for genomic footprints of parallel evolution of the plants morphospace explaining convergent phenotypes and also selected complex traits. It is often seen that some of the characters and traits are combined and show even convergence as a syndrome. Here we focus on one of the most extreme traits, namely evolution of monocarpic (annual) versus polycarpic (perennial) life history, which has evolved many times independently in Brassicaceae. Spatio-temporal environmental evidence will be collected indirectly from data on distribution ranges and divergence time estimates. We seek for deepening our insights into the principles of Brassicaeae evolution in order to understand better the successfully evolutionary history of a large plant family diversifying at highest rates.