Ecological genomics of developmental timing

植物生物学的主要目标之一是描述基因在序列水平上的变异是如何产生表型变异的。快速进展的一个领域是描述遗传模式植物拟南芥（a.thaliana）中调控基因的变异如何影响关键发育性状的变异，即从营养生长向生殖生长的转变。尽管取得了这些进展，但尚不清楚这些变异中有多少是适应性的。我将研究在拟南芥的入侵种群中，发育时间和对寒冷的发育敏感性（即这些特征与地理因素之间的关系）是否已经进化，与我在欧洲样本中检测到的相似。入侵物种的平行曲线将有力地证明拟南芥在发育时间和发育敏感性上的变化是适应性的。我还将研究两个主要的发育基因，FRI和FLC，是否在北美是可变的，并导致这些性状和适合度的地理差异。我的具体目标是：(1)在广泛的地理范围内收集一组北美拟南芥生态型，并对其进行基因分型，建立大量SNP标记，以评估种群遗传结构和连锁不平衡；(2)利用这些北美拟南芥群体的SNP数据和已发表的欧亚样本SNP数据，将北美入侵物种置于全球系统地理背景中；(3)检验北美物种之间是否存在发育时间上的平行倾斜；如果依赖于FRI功能，那么(4)测试北美材料对冷的发育敏感性的平行地理差异，(5)在田间场地中FRI和FLC的植物系变量，并测量这些位点上等位基因频率的自然变化。该研究将评估分子遗传和环境变异在形成复杂性状中的作用，并对遗传和进化的并行性进行测试，这将有助于培养一些HQP，并推进我们对入侵物种的发育时间、植物繁殖和遗传学的认识。

One of plant biology's major goals is to describe how variation in genes at the sequence level creates phenotypic variation. One area of rapid progress has been describing how variation at regulatory genes in the genetic model plant, A. thaliana, affects variation in a key developmental trait, the transition from vegetative to reproductive growth. Despite this progress, it is unclear how much of this variation is adaptive.   I will investigate whether clines in development timing and developmental sensitivity to cold (i.e., relationships between these traits and geographic factors) have evolved in invasive populations of A. thaliana, parallel to clines I detected in European samples. Parallel clines in invasives would be strong evidence that the variation in developmental timing and developmental sensitivity in A. thaliana is adaptive. I will also investigate if two major developmental genes, FRI and FLC, are variable in N. America and lead to geographic variation in these traits and fitness.   My specific aims are to: (1) Collect a set of North American A. thaliana ecotypes over a broad geographic range, and genotype them for a large set of SNP markers to assess population genetic structure and linkage disequilibrium, (2) Use these SNP data for N. American A. thaliana populations and published SNP data on Eurasian samples to place N. American invasives into a global phylogeographic context, (3) Test whether a parallel cline in developmental timing has evolved among N. American accessions, and if  it depends on FRI functionality, (4) Test for parallel geographic divergence in developmental sensitivity to cold in N. American accessions, (5) Plant lines variable for both FRI and FLC into field sites, and measure natural changes in allele frequency at these loci. The proposed work will support training several HQP and advance our knowledge of developmental timing, plant reproduction, and the genetics of invasive species because it evaluates the roles of molecular genetic and environmental variation in shaping complex traits, and tests for genetic and evolutionary parallelism.