indel, insertion/deletion

  • 文章类型: Journal Article
    虽然大量的研究工作已经放在了解植物蛋白与它们的分子伴侣的相互作用,与其他生物体的研究相比,植物中的研究相对较少,涉及这些相互作用是如何演变的。人们认为祖先蛋白质比现代蛋白质更混杂,并且特异性通常在基因复制和随后的功能精炼之后进化。然而,祖先蛋白质复活研究发现,一些现代蛋白质是由缺乏这些功能的祖先从头进化而来的。有趣的是,新的相互作用是由于少数突变而进化的,因此,获得新功能似乎既不困难也不罕见,然而,它们中只有少数在丢失到随后的突变之前被整合到生物过程中。这里,我们详细介绍了祖先序列重建(ASR)的方法,提供引物来重建祖先基因的序列。在讨论在植物中使用祖先重建的少数实例之前,我们将介绍一系列不同真核生物的案例研究。当ASR被用来挖掘遥远的进化历史时,我们还将提出一些替代遗传方法来研究较短时间尺度上的分子进化。我们认为,植物次生代谢的研究特别适合于祖先重建研究。的确,它古老的进化根源和高度多样化的景观提供了一个理想的环境,在其中解决围绕进化新颖性出现的焦点问题,以及这如何影响植物代谢的化学多样化。
    Whilst substantial research effort has been placed on understanding the interactions of plant proteins with their molecular partners, relatively few studies in plants - by contrast to work in other organisms - address how these interactions evolve. It is thought that ancestral proteins were more promiscuous than modern proteins and that specificity often evolved following gene duplication and subsequent functional refining. However, ancestral protein resurrection studies have found that some modern proteins have evolved de novo from ancestors lacking those functions. Intriguingly, the new interactions evolved as a consequence of just a few mutations and, as such, acquisition of new functions appears to be neither difficult nor rare, however, only a few of them are incorporated into biological processes before they are lost to subsequent mutations. Here, we detail the approach of ancestral sequence reconstruction (ASR), providing a primer to reconstruct the sequence of an ancestral gene. We will present case studies from a range of different eukaryotes before discussing the few instances where ancestral reconstructions have been used in plants. As ASR is used to dig into the remote evolutionary past, we will also present some alternative genetic approaches to investigate molecular evolution on shorter timescales. We argue that the study of plant secondary metabolism is particularly well suited for ancestral reconstruction studies. Indeed, its ancient evolutionary roots and highly diverse landscape provide an ideal context in which to address the focal issue around the emergence of evolutionary novelties and how this affects the chemical diversification of plant metabolism.
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  • 文章类型: Journal Article
    遗传变异是疾病易感性的主要决定因素,对治疗的反应,和临床结果。短读测序技术的进展,尽管有一些缺点,能够识别每个基因组中的绝大多数遗传变异。主要挑战是识别心血管疾病中的致病变体。由于技术缺陷和我们对心血管疾病的遗传基础的不完全理解,基因检测的产量受到限制。为了推进这个领域,向长读取测序平台的转变是必要的.此外,为了辨别致病变异,遗传疾病应被视为一个连续体,遗传变异应被视为具有梯度效应大小的概率因素。此外,具有临床医学和分子遗传学专业知识的疾病特异性医师-科学家最有能力辨别遗传变异的功能和临床意义。这些变化有望增强遗传发现的临床效用。
    Genetic variants are major determinants of susceptibility to disease, response to therapy, and clinical outcomes. Advances in the short-read sequencing technologies, despite some shortcomings, have enabled identification of the vast majority of the genetic variants in each genome. The major challenge is in identifying the pathogenic variants in cardiovascular diseases. The yield of the genetic testing has been limited because of technological shortcomings and our incomplete understanding of the genetic basis of cardiovascular disorders. To advance the field, a shift to long-read sequencing platforms is necessary. In addition, to discern the pathogenic variants, genetic diseases should be considered as a continuum and the genetic variants as probabilistic factors with a gradient of effect sizes. Moreover, disease-specific physician-scientists with expertise in the clinical medicine and molecular genetics are best equipped to discern functional and clinical significance of the genetic variants. The changes would be expected to enhance clinical utilities of the genetic discoveries.
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  • 文章类型: Journal Article
    最近的研究表明,癌症是由于肿瘤DNA中驱动体细胞事件的阳性选择而产生的,负面选择只扮演次要角色,如果有的话。然而,这些研究涉及非重复序列的改变,没有考虑在本研究中研究的显示错配修复缺陷导致的微卫星不稳定性(MSI)的肿瘤中具有非常高的病理生理相关性的重复序列中的突变.
    我们对47例MSI结直肠癌(CRC)进行了全外显子组测序,并在53例MSICRC的独立队列中证实了结果。我们使用了微卫星内突变事件的概率模型,同时调整预先存在的模型来分析非重复DNA序列。研究了MSICRC中的阴性选择的编码改变在CRC细胞系和164名MSICRC患者的第三组中的功能和临床影响。
    观察到DNA重复序列中体细胞突变的阳性和阴性选择,引导我们确定与MSI驱动的致瘤过程相关的预期真正的驱动基因。几个编码负选择的MSI相关突变事件(n=5)显示对肿瘤细胞具有有害作用。在尽管阴性选择仍观察到有害MSI突变的肿瘤中,它们与MSICRC患者的生存率较差相关(风险比,3;95%CI,1.1-7.9;P=0.03),提示它们的抗癌作用应被其他未知的致癌过程所抵消,这些过程会导致预后不良。
    本结果确定了在MSI驱动的肿瘤发生中起作用的阳性和阴性驱动体细胞突变,表明MSICRC中的基因组不稳定性在实现肿瘤细胞转化中起着双重作用。外显子组测序数据已保存在欧洲基因组-表型档案中(登录号:EGAS00001002477)。
    Recent studies have shown that cancers arise as a result of the positive selection of driver somatic events in tumor DNA, with negative selection playing only a minor role, if any. However, these investigations were concerned with alterations at nonrepetitive sequences and did not take into account mutations in repetitive sequences that have very high pathophysiological relevance in the tumors showing microsatellite instability (MSI) resulting from mismatch repair deficiency investigated in the present study.
    We performed whole-exome sequencing of 47 MSI colorectal cancers (CRCs) and confirmed results in an independent cohort of 53 MSI CRCs. We used a probabilistic model of mutational events within microsatellites, while adapting pre-existing models to analyze nonrepetitive DNA sequences. Negatively selected coding alterations in MSI CRCs were investigated for their functional and clinical impact in CRC cell lines and in a third cohort of 164 MSI CRC patients.
    Both positive and negative selection of somatic mutations in DNA repeats was observed, leading us to identify the expected true driver genes associated with the MSI-driven tumorigenic process. Several coding negatively selected MSI-related mutational events (n = 5) were shown to have deleterious effects on tumor cells. In the tumors in which deleterious MSI mutations were observed despite the negative selection, they were associated with worse survival in MSI CRC patients (hazard ratio, 3; 95% CI, 1.1-7.9; P = .03), suggesting their anticancer impact should be offset by other as yet unknown oncogenic processes that contribute to a poor prognosis.
    The present results identify the positive and negative driver somatic mutations acting in MSI-driven tumorigenesis, suggesting that genomic instability in MSI CRC plays a dual role in achieving tumor cell transformation. Exome sequencing data have been deposited in the European genome-phenome archive (accession: EGAS00001002477).
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  • 文章类型: Journal Article
    赖氨酸特异性脱甲基酶1B(KDM1B)在调节组蛋白3的赖氨酸4的甲基化状态中起着至关重要的作用,对男性生育力很重要。本研究的目的是探索KDM1BmRNA表达谱,并鉴定猪KDM1B基因的新遗传变异,以及确定这些变异与雄性仔猪睾丸测量性状之间的关联。KDM1BmRNA表达谱表明该基因在所有测试器官中广泛表达。此外,在KDM1B基因中发现了一个新的17bp缺失(NC_010449.4:g.31142_31159delCATGGATAGTAGTTGCT)。值得注意的是,该缺失序列与NCBI的预测不一致。关联分析表明,在40日龄大型白猪中,17bp的indel位点与睾丸重量显着相关(P<0.05)。此外,通过生物信息学分析,转录因子热休克因子-1可以结合17bp序列。这些结果不仅扩展了猪KDM1B基因的遗传变异,而且有助于在猪育种中实施标记辅助选择。
    Lysine-specific demethylase 1B (KDM1B) which plays a crucial role in regulating methylation status at lysine 4 of histone 3 is important for male fertility. The aim of this study was to explore the KDM1B mRNA expression profiles and to identify novel genetic variants of the pig KDM1B gene, as well as to determine the association between these variants and testis measurement traits in male piglets. The KDM1B mRNA expression profiles indicated that this gene widely expressed in all tested organs. In addition, a novel 17-bp deletion (NC_010449.4:g.31142_31159delCATGGATAGTAGTTGCT) within KDM1B gene was found. Notably, this deletion sequence was inconsistent with the prediction by NCBI. Association analysis revealed that the 17-bp indel locus was significantly associated with the testis weight in 40-day-old Large White pigs (P < 0.05). Furthermore, through bioinformatics analysis, transcriptional factor heat shock factor-1 could combine the 17-bp sequence. These results not only extend the genetic variations of the pig KDM1B gene but also contribute to implementing marker-assisted selection in pig breeding.
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