Mapping Recombination Nodules on Synaptonemal Complexes of Maize

9728673对玉米联会复合体(SCs)上的重组结瘤(RN)的分析将被用于确定KYS玉米的杂交模式。由于每个RN可靠地标记了遗传交叉事件的位置，因此在SCs上定位RN是一种高分辨率的方法，可以检查整个染色体组的每个二价体上的交叉频率和分布，而不依赖于饱和或末端标记。将制备玉米干细胞的标准核型，并根据相对长度和臂比来鉴定每个SC，然后通过检查玉米10条染色体中每条染色体的倒位杂合子来将其与特定的染色体相关联。对每种类型的450-500个正常SC的检查将允许绘制沿10个玉米SC中每一个的RN分布和频率的详细地图。这些数据将被用来分析关于热点和冷点、臂内和臂之间的干扰以及端粒、动粒和异染色质等染色体特征的交叉。作为一个辅助项目，将研究倒置杂合性对交叉抑制和染色体内和染色体间干扰的影响，即舒尔茨-雷德菲尔德效应。将对玉米的野生祖先teosinte中的RN分布进行更有限的检查。已用于构建玉米分子连锁图谱的几个玉米品种(TX303、CO 159、B73和No17)(以及一些对育种工作有重要意义的品种)将作为测试品系，在选择一个品系进行完整分析之前，确定该方法的普遍适用性。玉米的RN图谱将是一个重组的物理图谱，它将补充现有的玉米基因和分子连锁图谱，因此在基础研究和育种计划的基因组学方法中都将是重要的。

9728673 Stack An analysis of recombination nodules (RNs) on synaptonemal complexes (SCs) will be used to determine the pattern of crossing over in KYS maize. Because each RN reliably marks the position of a genetic crossover event, mapping RNs on SCs is a high-resolution method to examine the frequency and distribution of crossing over on each bivalent of an entire set of chromosomes without dependence on saturation or terminal markers. A standard karyotype for maize SCs will be prepared and each SC on the basis of relative length and arm ratio will be identified and then related to a specific chromosome by examining inversion heterozygotes for each of the ten chromosomes of maize. An examination of 450-500 normal SCs of each type will allow a detailed map of the distribution and frequency of RNs along each of the ten maize SCs to be prepared. The data will be used to analyze crossing over in regard to hot and cold spots, interference within and between arms and chromosomal features such as telomeres, kinetochores, and heterochromatin. As an ancillary project, the influence of inversion heterozygosity on crossover suppression and interference within and between chromosomes, the Schultz-Redfield effect, will be investigated. A more limited examination of the distribution of RNs in teosinte, the wild progenitor of maize will be done. Several varieties of maize (TX303, CO 159, B73 and NO17) that have been used to prepare the molecular linkage map for maize, (as well as some that are important for breeding programs), will be used as test strains to determine the general applicability of the method before a strain is chosen for a complete analysis. An RN map for maize will be a physical map of recombination that will complement the existing gene and molecular linkage maps for maize and, as such, will be of importance in a genomic approach to both basic studies and breeding programs.