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Comparative phylogenomics of lateral gene transfers among grasses

草类横向基因转移的比较系统发育学

基本信息

批准号：
NE/V000012/1
负责人：
Luke Dunning
金额：
$ 66.18万
依托单位：
University of Sheffield
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2021
资助国家：
英国
起止时间：
2021 至无数据
项目状态：
未结题

来源：
https://gtr.ukri.org/projects?ref=NE%2FV000012%2F1
关键词：
Comparative phylogenomics lateral gene transfers

项目摘要

Natural selection acting on the genetic variation existing among individuals within a species is a major driving force in evolution. In multicellular organisms, such as animals and plants, novel genetic variants were assumed until recently to exclusively arise through random mutations in the genetic material passed from parents to offsprings. However, recent years have seen the accumulation of reports of gene transfers between distinct multicellular species in a process called lateral gene transfer (LGT). LGT can spread functional genes for adaptive traits among distant lineages, and in plants, it has facilitated the colonisation of low-light environments, improved efficiency of photosynthesis in high temperatures, and the ability to thrive on different soil types. LGT can therefore lead to big evolutionary leaps, allowing plants to rapidly evolve beyond their inherent potential. However, a high frequency of LGT would also suggest that genetic material might 'escape' from GM crops and be transferred to wild species. This could lead to the emergence of superweeds that would decrease crop yields and damage natural ecosystems. The evolutionary importance and frequency of LGT remain largely unknown due to a lack of dedicated efforts and sparse species sampling in previous studies. In this project, we will establish the importance of LGT for plant evolution by quantifying the phenomenon in various groups and establishing the factors that promote such gene transfers. Firstly, we will scan the genomes of numerous flowering plants capturing the diversity of the group to test the hypothesis that some lineages of plants are more likely to exchange genes than others. Secondly, we will analyse the LGT in multiple individuals of some grass species, the most important group of flowering plants ecologically and economically. From the distribution of LGT among individuals within each species our innovative approach will calculate the rates of gains of LGT independently from the rates of subsequent losses. This will allow us to test the hypothesis that the rate of random LGT gains is high in all species, but that the rate of subsequent losses varies because of different selection regimes. Thirdly, we will analyse the variation in the number of LGT donated by diverse grass species to determine whether the probability of being the source of the transfers depends on the evolutionary history, morphological characters or the geographic origin of the species. Our multidimensional project will provide a precise quantification of the amount of LGT gained and lost through time by diverse groups of plants. In addition, our innovative approach will establish the factors that increase the probability of transferring genes to distant relatives. This fundamental knowledge will be pivotal in establishing the importance of genetic exchanges between species on the ecological and functional diversification of plants, potentially leading to a reappraisal of the tree-of-life nature of evolution in multicellular organisms. In addition, the identification of the factors that promote LGT among grasses will help estimate the risk of gene escape from GM crops and develop mitigating strategies.

自然选择作用于物种内个体之间存在的遗传变异，是进化的主要驱动力。在多细胞生物中，如动物和植物，直到最近，新的遗传变异被认为是通过遗传物质从父母传给后代的随机突变而产生的。然而，近年来已经看到了不同的多细胞物种之间的基因转移的报告积累在一个过程中称为横向基因转移（LGT）。LGT可以在遥远的谱系中传播适应性性状的功能基因，在植物中，它促进了低光环境的定殖，提高了高温下的光合作用效率，以及在不同土壤类型中茁壮成长的能力。因此，LGT可以导致巨大的进化飞跃，使植物能够快速进化，超越其固有的潜力。然而，LGT的高频率也表明遗传物质可能从转基因作物中“逃逸”并转移到野生物种中。这可能导致超级杂草的出现，从而降低作物产量并破坏自然生态系统。由于缺乏专门的努力和稀疏的物种采样在以前的研究中，LGT的进化重要性和频率在很大程度上仍然未知。在这个项目中，我们将通过量化不同群体中的现象并确定促进这种基因转移的因素来确定LGT对植物进化的重要性。首先，我们将扫描许多开花植物的基因组，捕捉群体的多样性，以检验某些植物谱系比其他植物更有可能交换基因的假设。其次，我们将分析在多个个体的一些草类，最重要的群体开花植物的生态和经济的LGT。根据LGT在每个物种内个体之间的分布，我们的创新方法将独立于随后的损失率来计算LGT的收益率。这将使我们能够测试的假设，随机LGT增益率在所有物种都很高，但随后的损失率因不同的选择制度而异。第三，我们将分析不同草种捐赠的LGT数量的变化，以确定是否是转移来源的概率取决于物种的进化历史，形态特征或地理起源。我们的多维项目将提供不同植物群体随时间推移获得和损失的LGT数量的精确量化。此外，我们的创新方法将确定增加将基因转移到远亲的可能性的因素。这一基本知识将是至关重要的，在建立物种之间的生态和功能多样化的植物的遗传交换的重要性，可能导致重新评估的生命树的性质在多细胞生物体的进化。此外，确定促进禾本科植物LGT的因素将有助于估计转基因作物基因逃逸的风险，并制定缓解策略。