Chromatin and recombination landscapes in the hexaploid wheat genome.

减数分裂重组在有性繁殖物种的后代中产生遗传多样性。例如，同源染色体之间的相互交换（称为交叉）产生新的遗传变异组合。减数分裂过程中的变异产生过程仍然是作物改良的主要工具，因此可以将来自不同背景的有用特征结合起来。面包小麦是英国和全球的主要作物，在育种过程中减数分裂重组仍然是品种改良的重要工具。然而，小麦基因组非常大（17千兆酶），并且表现出高度倾斜的重组分布，大多数交叉发生在染色体的远端区域。这严重限制了育种者利用位于染色体中心区域的变异的能力。因此，开发控制小麦重组的工具和技术直接关系到粮食安全。在这个项目中，学生将使用染色质免疫沉淀（ChIP）和高通量测序来分析整个小麦基因组中常染色质和异染色质修饰的分布。这些分布将与KWS和基因型产生的高分辨率遗传图谱有关，这些基因型在遗传强度上存在差异。这些实验将在KWS感兴趣的背景下进行，学生将识别与改变频率和重组模式相关的染色质模式。最近公开发布的高质量小麦参考基因组组合使该项目可行且及时。新的反向遗传资源（例如TILLING， CRISPR-Cas9）允许在面包小麦中破坏感兴趣的基因。为了从功能上研究染色质在重组中的作用，学生将分离表观遗传调控因子的突变。这些突变体将使用ChIP-seq进行分析，以表征染色质如何在全基因组范围内改变。最后，这些突变体将用于测量减数分裂期间重组事件的数量和分布的影响。该项目将为学生提供小麦遗传学和基因组学方面的高级培训。它们将产生对理解小麦基因组功能和进化具有重要基础意义的数据。他们将获得与学术和工业科学背景相关的小麦遗传学经验。

Meiotic recombination creates genetic diversity in the progeny of sexually reproducing species.For example, reciprocal exchange between homologous chromosomes (known as crossover)creates novel combinations of genetic variation. The variation-generating processes actingduring meiosis remain a major tool for crop improvement, whereby useful characteristics fromdifferent backgrounds can be combined.Bread wheat is a major crop in the UK and globally, where meiotic recombination duringbreeding remains an essential tool for variety improvement. However, the wheat genome isextremely large (17 gigabases) and shows highly skewed recombination distributions, with mostcrossovers occurring in the distal regions of the chromosomes. This severely limits the ability ofbreeders to utilise variation located in the central regions of the chromosomes. Therefore,developing tools and technologies to control recombination in wheat has direct relevance forfood security.In this project the student will use chromatin immunoprecipitation (ChIP) followed by highthroughput sequencing to profile the distribution of euchromatic and heterochromatic chromatinmodifications throughout the wheat genome. These distributions will be related to highresolutiongenetic maps generated by KWS and genotypes that differ in their genetic maplengths. These experiments will be conducted in backgrounds of interest to KWS and thestudent will identify chromatin patterns that correlate with altered frequencies and patterns ofrecombination. The recent public release of a high quality reference genome assembly for wheatmakes this project feasible and timely.New reverse genetic resources (e.g. TILLING, CRISPR-Cas9) are available that allow genes ofinterest to be disrupted in bread wheat. To functionally investigate the role of chromatin onrecombination the student will isolate mutations in epigenetic regulators. These mutants will beprofiled using ChIP-seq in order to characterise how chromatin is altered genome-wide. Finally,these mutants will be used to measure effects on number and distribution of recombinationevents during meiosis.This project will provide the student with advanced training in wheat genetics and genomics.They will generate data of basic importance for understanding wheat genome function andevolution. They will gain experience in wheat genetics relevant to both academic and industrialscientific contexts.