Getting to the Root of Flexible Stems: The Primary Cilia as a Proximate Mechanism of Plasticity and Evolution of the Cichlid Jaw

随着时间的推移，生物多样性是如何产生和维持的，仍然是一个重要的研究领域。适应性辐射代表了形态进化响应离散生态变化的极端情况，被认为对地球上的生物多样性做出了重大贡献。这项研究试图识别和描述促进适应性辐射的遗传和细胞机制，从而为生物多样性的起源提供新的见解。这一高度跨学科的项目提供了丰富的智力景观，以培训学生的各种方法和理论。它还提供了一个明确的框架，以开发向公众传达进化论原理的教学工具。这将是正在进行的一系列努力的一部分，以开发一系列动画和互动的进化“起源故事”，详细说明显著特征发展和进化的遗传机制，包括龟壳、蝙蝠翅膀和鲸鱼的肢体丧失。在这里，研究小组提出了一个新的章节--做鬼脸：鱼是如何改变它的头骨的。这个项目的焦点是表型可塑性，它指的是有机体对环境变化做出反应而改变外表的能力。个体在不同环境中改变表型的能力可能会增加其在变化和/或波动的环境中的适应性，这表明可塑性可能是适应性的，因此受制于选择本身。据预测，生活在波动环境中的物种将保持高度的可塑性。相反，生活在更稳定环境中的物种预计会失去启动塑料反应的能力，并表现出固定的表型。不幸的是，表型可塑性的严格遗传基础仍然难以捉摸，因此这一特征的进化潜力在很大程度上仍然未知。这项研究的目的是描述硬骨颌骨表型可塑性的分子基础。对下巴的重视具有直接的生态后果，因为不同的下巴形状将决定鱼生活在哪里以及它以什么为食。突变和转基因斑马鱼将被用来评估参与骨形成的关键分子，包括那些支撑初级纤毛和刺猬信号的分子，在多大程度上促进头骨和颌骨的表型可塑性。然后，将把构成可塑性的分子机制与教科书中的遗传进化模式进行比较，这本教科书名为东非慈唇鱼，它们的下巴形状表现出广泛的多样性。据预测，构成喂食器可塑性的基因也是颌骨进化的基础。这是因为，随着种群随着时间的推移适应新的环境，导致可塑性的遗传变异被预测为“固定的”。总而言之，该奖项下的研究将有助于更好地理解基因组和环境如何相互作用来促进生物多样性。

How biodiversity arises and is maintained over time remains an important area of study. Adaptive radiations represent extreme instances of morphological evolution in response to discrete ecological shifts, and are thought to have made significant contributions to biodiversityon this planet. This research seeks to identify and characterize the genetic and cellular mechanisms that promote adaptive radiations, and thus to provide novel insights into the origins of biodiversity. This highly interdisciplinary project provides a rich intellectual landscape to train students in various methods and theories. It also offers an explicit framework to develop pedagogical tools for conveying evolutionary principals to the public. This will be part of on-going efforts to develop a series of animated and interactive evolutionary "origin stories" that detail the genetic mechanisms that underlie the development and evolution of notable traits, including turtle shells, bat wings, and limb loss in whales. Here the team proposes a new chapter-- Making faces: How the fish changes its skull.A focal point of this project is phenotypic plasticity, which refers to the ability of an organism to change its appearance in response to a change in the environment. The ability of an individual to change its phenotype in different environments may increase its fitness in changing and/or fluctuating environments, which suggests that plasticity may be adaptive and therefore subject to selection itself. It is predicted that species that live in fluctuating environments will maintain a high degree of plasticity. Conversely, species that live in more stable environments are predicted to loose the ability to mount a plastic response, and exhibit fixed phenotypes. Unfortunately, a strict genetic basis for phenotypic plasticity has remained elusive, and thus the evolutionary potential for this trait remains largely unknown. The goal of this research is to characterize the molecular basis for phenotypic plasticity of the teleost jaw. An emphasis on the jaws has direct ecological consequences, as different jaw shapes will determine where a fish lives and what it feeds on. Mutant and transgenic zebrafish will be used to assess the degree to which key molecules involved in bone formation, including those that underlie the primary cilia and Hedgehog signaling, are necessary to promote phenotypic plasticity in the skull and jaws. The molecular mechanisms that underlie plasticity will then be compared to patterns of genetic evolution in a textbook adaptive radiation, East African cichlid fishes, which exhibit extensive diversity in the shape of their jaws. It is predicted that the genes that underlie plasticity of the feeding apparatus, also underlie evolution of the jaws. This is because genetic variation that leads to plasticity is predicted to become "fixed" as populations adapt to new environments over time. In all, research under this award will facilitate a better understand of how the genome and environment interact to promote biodiversity.