Character evolution in pleurocarpous mosses: a phylogenetic study focusing on the Lembophyllaceae/Neckeraceae - clade

附生胸骨藓的形态多样性及其近期的快速辐射是苔藓学中最具挑战性的问题之一。由于目前的特征进化概念在很大程度上是误导性的，因此需要结合分子和形态数据进行全面的系统发育分析，这对于理解胸骨藓类植物的进化至关重要。在本研究中，我们将重点研究两个密切相关的科，lemmbophyllaceae和Neckeraceae。本研究的目的是：1)利用形态学和DNA序列数据重建有充分支持的科系系统发育；2)确定胸骨鲤科/龙骨鲤科的祖先枝；3)研究胸骨鲤科形态特征的进化。系统发育分析将包括最先进的方法，如最大似然，贝叶斯推理以及基于简约的方法。系统发育分析将进行a)在DNA/RNA二级结构计算和分子模式分析的指导下，对人工对齐的序列数据进行分析，以及b)应用直接优化一种新的基于简约的算法。深入的分析将为研究胸鱼分子进化的模式和速率提供新的见解，提出新的类群系统发育概念，并确定形态学上的突触。我们将澄清目前使用的诊断形态特征的进化是否是一个独立的适应性进化的结果，特别是对附生栖息地的进化，这种栖息地在采样谱系中独立发生了几次，也许在一般的胸果藓类中。

The morphological diversity of epiphytic pleurocarpous mosses and their recent rapid radiation is one of the most challenging problems in bryology. As current concepts of character evolution are largely misleading, thorough phylogenetic analyses combining molecular and morphological data are needed and crucial for understanding the evolution of pleurocarpous mosses. In this study we will focus on two closely related families, Lembophyllaceae and Neckeraceae. Aims of this study are: 1) to reconstruct well supported phylogenies of the families using both morphological and DNA sequence data 2) to pinpoint the ancestral clades of the Neckeraceae/Lembophyllaceae within pleurocarps, and 3) to study the evolution of morphological characters within this group. The phylogenetic analyses will comprise state of the art approaches such as maximum likelihood, Bayesian inference as well as parsimony-based methods. Phylogenetic analyses will be performed a) on manually aligned sequence data, guided by DNA/RNA secondary structure calculations and analyses of molecular patterns, and b) applying direct optimization a novel parsimony-based algorithm. The thorough analyses will provide new insights into the modes and rates of molecular evolution in pleurocarps, present a new phylogenetic concept of the study group and identify morphological synapomorphies. We will clarify if the evolution of the currently used diagnostic morphological traits is a result of an independent adaptive evolution, especially to epiphytic habitats that occurred several times independently in the sampled lineages and perhaps in pleuocarpous mosses in general.