Maternal Genetic Effects Shape Developmental Evolution

项目总结 母体基因组的变异改变了后代的供养方式，并改变了后代的许多方面 发展。这些发育变化对后代的表型、生活史、 和健身。长期以来，母体效应一直被认为是发育的一个主要因素，而自然 不同母体背景之间发生的差异具有改变发育命运的深远潜力。然而， 涉及的具体机制和遗传位点仍然知之甚少。最近，母体遗传 影响已被公认为是人类健康和发展的主要贡献者，其母体-- 合子上位性相互作用。在这里，我使用Streblospio Benedicti，一种新兴的模式来理解 母体遗传效应影响发育计划的演变。本尼迪克蒂菌株产生两个 不同的后代类型，在卵子大小、胚胎发育和幼虫发育方面不同。因此，S.benedicti是一种 间接发展和直接发展之间的进化共同过渡的种内模型，以及它 仍然是已知的唯一有两种可遗传后代类型的生物。使用S.benedicti，我已经证明了 从间接发展向直接发展的转变需要两者的独立演变和协调 母体和受精卵基因组。转基因和测序技术的最新进展 对新兴模型的研究是可行的，我在S.benedicti中开发了分子和基因组工具来回答 这些关键问题；我已经构建了遗传图谱，一个完全组装和注释的基因组， 转录组数据库，以及用于制作转基因的方法。这项提案中的研究将是 首先研究进化发育转变的种内遗传基础和意志 回答关于母体基因组在塑造发育中的作用的长期存在的问题 程序。在这里，我使用了卵母细胞、胚胎和 单卵裂球水平，允许对异时性、异位性和异构性基因进行量化 跨不同开发类型的表达式。这一方法揭示了1)基因组水平的调控 改变发展的建筑，2)母性因素在启动发展和生命历史中的作用 转变，以及3)参与这些变化的特定基因。通过将转录组学与种群相结合 基因组数据，我将产生一组互补的候选基因，参与进化-发育 我将在未来的研究中验证这一点。这一建议利用了遗传上易驯服的 在多个尺度上回答基本进化问题的本氏链球藻发育二型性， 从分子水平到种群水平。在S.benedicti中发现的由此产生的遗传结构和基因座是 在不同的有机体中具有可比性。这个项目将揭示其结构和遗传机制。 通过母体遗传效应塑造发育进化并导致小说 发展计划。

PROJECT SUMMARY Variation in the maternal genome alters the way offspring are provisioned and changes many aspects of their development. These changes in development have cascading effects on the offspring phenotype, life-history, and fitness. Maternal effects have long been recognized as a major factor in development, and the naturally occurring variation across maternal backgrounds has profound potential to alter developmental fates. However, the specific mechanisms and genetic loci involved remain poorly understood. Recently, maternal genetic effects have been recognized as a major contributor to human health and development through maternal-by- zygotic epistatic interactions. Here I use Streblospio benedicti, an emerging model, to understand how maternal genetic effects influence the evolution of developmental programs. S. benedicti produces two distinct offspring types that differ in egg size, embryogenesis, and larval development. Thus, S. benedicti is an intraspecific model for the evolutionarily common transition between indirect and direct development, and it remains the only known organism to have two heritable offspring types. Using S. benedicti I have shown that a transition from indirect to direct development requires the independent evolution and coordination of both maternal and zygotic genomes. Recent advances in transgenics and sequencing technologies have made research on emerging models feasible, and I developed molecular and genomic tools in S. benedicti to answer these crucial questions; I have constructed the genetic map, a fully assembled and annotated genome, transcriptome databases, and methods for making transgenics. The research in this proposal will be the first to investigate the intraspecific genetic basis for evolutionary developmental transitions and will answer long-standing questions of the role of the maternal genome in shaping developmental program. Here I use comparative transcriptomics across the developmental types at the oocyte, embryo, and single-blastomere level, allowing quantification of heterochronic, heterotopic, and heterometric gene expression across different development types. This approach reveals 1) the genomic-level regulatory architecture that alters development, 2) the role of maternal factors in initiating developmental and life-history transitions, and 3) the specific genes involved in these changes. By integrating transcriptomics with population genomic data, I will produce a complementary set of candidate genes involved in evolutionary-developmental transitions, which I will validate in future studies. This proposal leverages the genetically tractable developmental dimorphism in S. benedicti to answer fundamental evolutionary questions at multiple scales, from the molecular to population level. The resulting genetic architecture and loci found within S. benedicti are comparable across divergent organisms. This project will reveal the architecture and genetic mechanisms through which maternal genetic effects shape developmental evolution and lead to novel developmental programs.