Meiotic recombination: how has this adaptive and evolutionary force been influenced by domestication and selective breeding?

植物驯化和农业起源可以追溯到大约10,000年前，并对基因组进化产生了深远的影响，野生祖先和驯化作物之间的显著表型差异证明了这一点。从野生植物到驯化植物的转变以及随后的选择性育种导致了遗传多样性的减少。在这一建议中，我们提出减数分裂重组在作物遗传多样性减少以及野生物种和作物物种之间遗传多样性差异方面发挥了关键作用。减数分裂重组是生殖细胞有性繁殖的基本过程，它在染色体之间交换遗传信息，打破基因之间的联系，形成新的等位基因组合。减数分裂重组是植物基因组进化和适应当地环境以及育种过程的强大动力，减数分裂重组和育种过程中的密集选择对植物基因组进化产生了很大的影响，但这两个过程是如何联系在一起的尚不清楚。在这个项目中，我们将评估减数分裂过程如何在育种过程中发生分歧，以有效地减少作物的遗传变异。我们将使用先进的基因组技术对与减数分裂重组蛋白结合的DNA分子进行测序，并描绘野生小麦和驯化小麦全基因组减数分裂重组的图景。这些新的数据集将是独一无二的，因为它们的高分辨率，将允许我们探索基因的局部重组率，测试驯化的遗传效应，并了解自然环境和农业环境之间的不同进化轨迹。该项目还将解决一个基本的知识差距，因为它将确定在育种过程中经过严格选择的与农业相关的基因是否保留了重组特性，以便进一步改进遗传。将对海藻糖磷酸合成酶(TPS)和海藻糖磷酸磷酸酶(TPP)进行初步研究。TPS和TPS决定植物中糖的分配方式，这对植物对环境的适应、生长发育和作物产量有很大影响；它们是作物改良的重要目标。有了这个项目所产生的知识，就有可能了解在作物选择过程中，TPSS和TPP中的一些遗传变异是如何丢失的。我们还将调查减数分裂基因的局部重组率，以测试它们是否也被选择性育种所修复。这将使我们能够理解重要基因的遗传多样性的丧失如何降低了创造新的遗传多样性的适应潜力。总体而言，该项目将产生高分辨率和全基因组重组数据，以获得关于自然和农业环境之间基因进化的关键见解。我们的研究最初集中在三个基因家族，但在未来的研究中可能会扩展到任何基因家族。因此，该项目解决了进化生物学中的一个关键的基本问题，有可能就驯化的遗传效应建立新的概念，并促进NERC在“种群遗传学和进化”方面的战略使命。

Plant domestication and the origin of agriculture date from ca. 10,000 years ago and have had profound effects on genome evolution demonstrated in the dramatic phenotypic differences between wild progenitors and domesticated crops. The transition from wild to domesticated plants followed by selective breeding has led to a reduction of genetic diversity. In this proposal we propose that meiotic recombination has played a key role in the reduction of genetic diversity in crops and the difference in genetic diversification between wild and crop species. Meiotic recombination is the basic process of sexual reproduction in germs cells that exchanges genetic information between chromosomes breaking the linkage between genes to form new allelic combinations. Meiotic recombination is a powerful force for plant genome evolution and adaptation to local environment as well as during breeding.Meiotic recombination and the intense selection during breeding have highly influenced plant genome evolution, but it remains unclear how these two processes are connected. In this project, we will evaluate how meiotic processes have diverged during breeding to effectively reduce genetic variation in crops. We will use advanced genomic technologies to sequence the DNA molecules bound to meiotic recombination proteins and profile the landscape of meiotic recombination genome-wide in wild and domesticated wheat. These new datasets will be unique due to their high-resolution and will allow us to explore local recombination rate over genes to test the genetic effects of domestication and to understand the differing evolutionary trajectories between natural and agricultural environments. This project will also address an essential knowledge gap as it will determine if genes of agricultural relevance that have been under strong selection during breeding have retained recombinational properties for further genetic improvements. Initial investigations will be carried out on trehalose phosphate synthase (TPS) and trehalose phosphate phosphatase (TPP). TPSs and TPPs determine the way sugars in plants are allocated which strongly affects plant adaptation to environment, growth and development and crop yields; they are important targets in crop improvement. With the knowledge generated in this project it will be possible to understand how some of the genetic variation in TPSs and TPPs has been lost during the crop selection process. We will also investigate local recombination rate over meiotic genes to test whether they too have been fixed by selective breeding. This will enable us to understand how loss of genetic diversity for important genes has reduced the adaptive potential to create novel genetic diversity. Overall, this project will generate high resolution and genome-wide recombination data to gain key insights in gene evolution between natural and agricultural environments. Our research initially focuses on three gene families but could be extended to any gene families in future studies. Hence, this project addresses a key fundamental question in evolutionary biology with the potential to establish new concepts on the genetic effects of domestication and to promote the strategic mission of NERC in "Population genetics and evolution".