Identification of Loci Governing Craniofacial Abnormalities Using a Natural Model

描述（由申请人提供）：导致人类牙齿和颅面疾病完整谱的精确分子和遗传机制仍然未知。而不是孤立地经历颅面骨骼的畸变，受影响的个体经常表现出共同发生的缺陷。有害的多效性基因座在引起这些共病特征中的作用在很大程度上仍未被探索。为了解决这个问题，我们试图开发一个自然的模型系统，Astyanax mexicanus，强大的基因组分析。该模型系统由地上（表面）和地下（洞穴居住）的形式，表现出许多“退化”的表型。这些包括颅面骨表型（真皮骨碎片）和牙齿畸变（异位上颌牙），同时发生严重的色素沉着缺陷。我的研究计划的长期目标是确定和功能验证基因座导致我们的自然模型系统，Astyanax mexicanus颅面异常的光谱。该R03申请代表了实现这一目标的重要一步，具有两个具体目标：1）在密集分布的Astyanax连锁图谱的背景下定义颅面异常和色素沉着缺陷的遗传基础，以及2）利用组织特异性全基因组转录组分析鉴定控制颅面改变的候选基因。这项研究的中心假设是，自然界中存在的多种退行性表型是通过相同或紧密连锁的多效性基因座产生的。拟议的项目将利用高分辨率microCT X射线成像的一个大型的链接映射鱼类谱系。这种非侵入性的方法有助于共同分析可能受到相同遗传调节因子影响的其他性状。初步研究表明，Astyanax中12个颅面和牙齿特征的遗传基础，与其他非骨骼特征（例如，视力丧失、色素沉着减少）。这项研究旨在通过加速发现参与这一系列表型的候选基因，为未来的应用奠定基础。总之，该项目代表了连锁图谱，下一代测序方法和高分辨率表型分析的创新整合，以确定颅面和牙齿异常的遗传基础。这项拟议的研究意义重大，因为它将使后续的R 01水平的确定性研究成为可能，并且是连续研究的第一步，该连续研究旨在1）了解导致颅面缺陷的基因的精确功能作用以及相关的共病表型，和2）澄清脊椎动物正常颅面和牙齿发育的机制。

DESCRIPTION (provided by applicant): The precise molecular and genetic mechanisms leading to the complete spectrum of dental and craniofacial disorders in humans remain unknown. Rather than experiencing aberrations of the craniofacial skeleton in isolation, affected individuals frequently manifest co-occurring deficits. The role of deleterious, pleiotropic loci in causing these co-morbid features remains largely unexplored. To approach this problem, we seek to develop a natural model system, Astyanax mexicanus, for powerful genomic analyses. This model system consists of epigean (surface) and subterranean (cave-dwelling) forms that demonstrate numerous "degenerative" phenotypes. These include craniofacial bone phenotypes (dermal bone fragmentation) and dental aberrations (an ectopic maxillary tooth) co-occurring with severe pigmentation defects. The long term goal of my research program is to identify and functionally validate the loci causing this spectrum of craniofacial abnormalities in our natural model system, Astyanax mexicanus. This R03 application, which represents a significant step towards attaining this goal has two specific aims: 1) define the genetic bases for craniofacial abnormalities and pigmentation defects in the context of a densely-populated Astyanax linkage map, and 2) identify candidate genes governing craniofacial alterations utilizing tissue-specific whole genome transcriptome profiling. The central hypothesis of this research is that multiple degenerative phenotypes present in the natural world arise through the same, or closely linked, pleiotropic loci. The proposed project will utilize high-resolution microCT X-ray imaging of a large linkage-mapping fish pedigree. This non-invasive approach facilitates co-analysis of additional traits that may be influenced by the same genetic regulators. Preliminary studies indicate a genetic basis for 12 craniofacial and dental features in Astyanax, with overlap of numerous loci involved in other non-skeletal features (e.g., vision loss, pigmentation reduction). This study seeks to lay the groundwork for future applications by accelerating discovery of candidate genes involved in this constellation of phenotypes. In sum, this project represents an innovative integration of linkage mapping, next-generation sequencing approaches, and high-resolution phenotypic analyses to determine the genetic basis for craniofacial and dental abnormalities. The proposed research is significant because it will enable subsequent definitive studies at the R01 level, and is the first step in a continuum of research designed to 1) inform the precise functional role of genes causing craniofacial defects with associated co-morbid phenotypes, and 2) clarify mechanisms governing normal craniofacial and dental development in vertebrates.