The genetic basis for leaf shape diversity: exploiting the Arabidopsis relative Cardamine hirsuta

生物学的一个关键挑战是了解生物形式是如何产生的，以及它们多样性的基础。模型系统的遗传分析已经确定了塑造后生动物和种子植物身体计划的关键调节因子。然而，对于这些调控途径中守恒与分化的平衡如何产生多细胞真核生物巨大的形态多样性，人们知之甚少。回答这些问题的一个障碍是缺乏合适的实验平台，在这些平台上，遗传工具可以被用来在全基因组范围内明确地研究基因功能的进化，不偏不倚的方式。我们将拟南芥（Arabidopsis thaliana）的近亲小豆蔻（Cardamine hirsuta）发展成为研究形态进化的强大系统，为克服这一问题迈出了重要的一步。我们正在努力了解这些物种的叶片形态进化的分子机制，通过这些分子机制，拟南芥产生了简单的、未分裂的叶片，而毛藓则产生了具有不同小叶的解剖叶片。我们最近鉴定了一种新的叶片复杂性基因，这种基因在拟南芥基因组中是缺失的，这是一个关键的发现。在这里，我们建议进一步利用这一系统，首先通过阐明叶片几何多样性基础的遗传网络，其次，了解这种多样性是否在自然选择的响应中产生。

A key challenge in biology is to understand how organismal forms are generated and the basis for their diversity. Genetic analyses in model systems have identified key regulators sculpting the body plans of metazoa and seed plants. However, less is known about how the balance of conservation versus divergence in such regulatory pathways generated the tremendous morphological diversity of multicellular eukaryotes. One impediment to answering these questions is the paucity of suitable experimental platforms where genetic tools can be utilized to unambiguously study the evolution of gene function in a genome-wide, unbiased fashion. We have made an important step in overcoming this problem by developing the Arabidopsis thaliana relative Cardamine hirsuta into a powerful system for studying morphological evolution. We are working to understand the molecular mechanisms through which leaf morphology evolved in these species to produce simple, undivided leaves in A. thaliana and dissected leaves with distinct leaflets in C. hirsuta. Our recent identification of a novel leaf complexity gene that is absent from the A. thaliana genome is a key finding. Here, we propose to exploit this system further, first by elucidating the genetic networks underlying the basis for diversity in leaf geometry and second, to understand whether such diversity arose in response to natural selection.