scholarly journals Patterns of gene evolution following duplications and speciations in vertebrates

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e8813 ◽  
Author(s):  
Kyle T. David ◽  
Jamie R. Oaks ◽  
Kenneth M. Halanych

Background Eukaryotic genes typically form independent evolutionary lineages through either speciation or gene duplication events. Generally, gene copies resulting from speciation events (orthologs) are expected to maintain similarity over time with regard to sequence, structure and function. After a duplication event, however, resulting gene copies (paralogs) may experience a broader set of possible fates, including partial (subfunctionalization) or complete loss of function, as well as gain of new function (neofunctionalization). This assumption, known as the Ortholog Conjecture, is prevalent throughout molecular biology and notably plays an important role in many functional annotation methods. Unfortunately, studies that explicitly compare evolutionary processes between speciation and duplication events are rare and conflicting. Methods To provide an empirical assessment of ortholog/paralog evolution, we estimated ratios of nonsynonymous to synonymous substitutions (ω = dN/dS) for 251,044 lineages in 6,244 gene trees across 77 vertebrate taxa. Results Overall, we found ω to be more similar between lineages descended from speciation events (p < 0.001) than lineages descended from duplication events, providing strong support for the Ortholog Conjecture. The asymmetry in ω following duplication events appears to be largely driven by an increase along one of the paralogous lineages, while the other remains similar to the parent. This trend is commonly associated with neofunctionalization, suggesting that gene duplication is a significant mechanism for generating novel gene functions.

2017 ◽  
Author(s):  
David M. Emms ◽  
Steven Kelly

AbstractThe correct interpretation of a phylogenetic tree is dependent on it being correctly rooted. A gene duplication event at the base of a clade of species is synapamorphic, and thus excludes the root of the species tree from that clade. We present STRIDE, a fast, effective, and outgroup-free method for species tree root inference from gene duplication events. STRIDE identifies sets of well-supported gene duplication events from cohorts of gene trees, and analyses these events to infer a probability distribution over an unrooted species tree for the location of the true root. We show that STRIDE infers the correct root of the species tree for a large range of simulated and real species sets. We demonstrate that the novel probability model implemented in STRIDE can accurately represent the ambiguity in species tree root assignment for datasets where information is limited. Furthermore, application of STRIDE to inference of the origin of the eukaryotic tree resulted in a root probability distribution that was consistent with, but unable to distinguish between, leading hypotheses for the origin of the eukaryotes. In summary, STRIDE is a fast, scalable, and effective method for species tree root inference from genome scale data.


2016 ◽  
Author(s):  
Anil S. Thanki ◽  
Nicola Soranzo ◽  
Wilfried Haerty ◽  
Robert P. Davey

AbstractBackgroundGene duplication is a major factor contributing to evolutionary novelty, and the contraction or expansion of gene families has often been associated with morphological, physiological and environmental adaptations. The study of homologous genes helps us to understand the evolution of gene families. It plays a vital role in finding ancestral gene duplication events as well as identifying genes that have diverged from a common ancestor under positive selection. There are various tools available, such as MSOAR, OrthoMCL and HomoloGene, to identify gene families and visualise syntenic information between species, providing an overview of syntenic regions evolution at the family level. Unfortunately, none of them provide information about structural changes within genes, such as the conservation of ancestral exon boundaries amongst multiple genomes. The Ensembl GeneTrees computational pipeline generates gene trees based on coding sequences and provides details about exon conservation, and is used in the Ensembl Compara project to discover gene families.FindingsA certain amount of expertise is required to configure and run the Ensembl Compara GeneTrees pipeline via command line. Therefore, we have converted the command line Ensembl Compara GeneTrees pipeline into a Galaxy workflow, called GeneSeqToFamily, and provided additional functionality. This workflow uses existing tools from the Galaxy ToolShed, as well as providing additional wrappers and tools that are required to run the workflow.ConclusionsGeneSeqToFamily represents the Ensembl Compara pipeline as a set of interconnected Galaxy tools, so they can be run interactively within the Galaxy’s user-friendly workflow environment while still providing the flexibility to tailor the analysis by changing configurations and tools if necessary. Additional tools allow users to subsequently visualise the gene families produced by the workflow, using the Aequatus.js interactive tool, which has been developed as part of the Aequatus software project.


2019 ◽  
Author(s):  
Eric L. Patterson ◽  
Christopher A. Saski ◽  
Daniel B. Sloan ◽  
Patrick J. Tranel ◽  
Philip Westra ◽  
...  

ABSTRACTIncreased copy number of the 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) gene confers resistance to glyphosate, the world’s most-used herbicide. There are typically three to eight EPSPS copies arranged in tandem in glyphosate-resistant populations of the weed kochia (Kochia scoparia). Here, we report a draft genome assembly from a glyphosate-susceptible kochia individual. Additionally, we assembled the EPSPS locus from a glyphosate-resistant kochia plant by sequencing a kochia bacterial artificial chromosome library. These resources helped reconstruct the history of duplication in the structurally complex EPSPS locus and uncover the genes that are co-duplicated with EPSPS, several of which have a corresponding change in transcription. The comparison between the susceptible and resistant assemblies revealed two dominant repeat types. We discovered a FHY3/FAR1-like mobile genetic element that is associated with the duplicated EPSPS gene copies in the resistant line. We present a hypothetical model based on unequal crossing over that implicates this mobile element as responsible for the origin of the EPSPS gene duplication event and the evolution of herbicide resistance in this system. These findings add to our understanding of stress resistance evolution and provide an example of rapid resistance evolution to high levels of environmental stress.


2020 ◽  
Author(s):  
Michael DeGiorgio ◽  
Raquel Assis

AbstractLearning about the roles that duplicate genes play in the origins of novel phenotypes requires an understanding of how their functions evolve. To date, only one method—CDROM—has been developed with this goal in mind. In particular, CDROM employs gene expression distances as proxies for functional divergence, and then classifies the evolutionary mechanisms retaining duplicate genes from comparisons of these distances in a decision tree framework. However, CDROM does not account for stochastic shifts in gene expression or leverage advances in contemporary statistical learning for performing classification, nor is it capable of predicting the underlying parameters of duplicate gene evolution. Thus, here we develop CLOUD, a multi-layer neural network built upon a model of gene expression evolution that can both classify duplicate gene retention mechanisms and predict their underlying evolutionary parameters. We show that not only is the CLOUD classifier substantially more powerful and accurate than CDROM, but that it also yields accurate parameter predictions, enabling a better understanding of the specific forces driving the evolution and long-term retention of duplicate genes. Further, application of the CLOUD classifier and predictor to empirical data from Drosophila recapitulates many previous findings about gene duplication in this lineage, showing that new functions often emerge rapidly and asymmetrically in younger duplicate gene copies, and that functional divergence is driven by strong natural selection. Hence, CLOUD represents the best available method for classifying retention mechanisms and predicting evolutionary parameters of duplicate genes, thereby also highlighting the utility of incorporating sophisticated statistical learning techniques to address long-standing questions about evolution after gene duplication.


2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Tianyu Zhou ◽  
Xiping Yan ◽  
Guosong Wang ◽  
Hehe Liu ◽  
Xiang Gan ◽  
...  

Peroxisome proliferators-activated receptor (PPAR) gene family members exhibit distinct patterns of distribution in tissues and differ in functions. The purpose of this study is to investigate the evolutionary impacts on diversity functions of PPAR members and the regulatory differences on gene expression patterns. 63 homology sequences of PPAR genes from 31 species were collected and analyzed. The results showed that three isolated types of PPAR gene family may emerge from twice times of gene duplication events. The conserved domains of HOLI (ligand binding domain of hormone receptors) domain and ZnF_C4 (C4 zinc finger in nuclear in hormone receptors) are essential for keeping basic roles of PPAR gene family, and the variant domains of LCRs may be responsible for their divergence in functions. The positive selection sites in HOLI domain are benefit for PPARs to evolve towards diversity functions. The evolutionary variants in the promoter regions and 3′ UTR regions of PPARs result into differential transcription factors and miRNAs involved in regulating PPAR members, which may eventually affect their expressions and tissues distributions. These results indicate that gene duplication event, selection pressure on HOLI domain, and the variants on promoter and 3′ UTR are essential for PPARs evolution and diversity functions acquired.


mSphere ◽  
2018 ◽  
Vol 3 (6) ◽  
Author(s):  
An Ngoc Nguyen ◽  
Elena Disconzi ◽  
Guillaume M. Charrière ◽  
Delphine Destoumieux-Garzón ◽  
Philippe Bouloc ◽  
...  

ABSTRACTCsrBs are bacterial highly conserved and multiple-copy noncoding small RNAs (sRNAs) that play major roles in cell physiology and virulence. In theVibriogenus, they are known to be regulated by the two-component system VarS/VarA. They modulate the well-characterized quorum sensing pathway controlling virulence and luminescence inVibrio choleraeandVibrio harveyi, respectively. Remarkably,Vibrio tasmaniensisLGP32, an oyster pathogen that belongs to theSplendidusclade, was found to have four copies ofcsrB, namedcsrB1-4, compared to two to three copies in otherVibriospecies. Here, we show that the extracsrB4copy results from acsrB3gene duplication, a characteristic of theSplendidusclade. Interestingly,csrBgenes are regulated in different ways inV. tasmaniensis, withcsrB1expression being independent of the VarS/VarA system. We found that a complex regulatory network involving CsrBs, quorum sensing, and the stationary-phase sigma factor σS redundantly but differentially controls the production of two secreted metalloproteases, Vsm and PrtV, the former being a major determinant of theV. tasmaniensisextracellular product toxicity. In particular, we identified a novel VarS/VarA-dependent but CsrB-independent pathway that controls positively both Vsm production and PrtV production as well asrpoSexpression. Altogether, our data show that acsrBgene duplication event inV. tasmaniensissupported the evolution of the regulatory network controlling the expression of major toxic secreted metalloproteases, thereby increasing redundancy and enabling the integration of additional input signals.IMPORTANCEThe conserved CsrB sRNAs are an example of sibling sRNAs, i.e., sRNAs which are present in multiple copies in genomes. This report illustrates how new copies arise through gene duplication events and highlights two evolutionary advantages of having such multiple copies: differential regulation of the multiple copies allows integration of different input signals into the regulatory network of which they are parts, and the high redundancy that they provide confers a strong robustness to the system.


2019 ◽  
Vol 20 (1) ◽  
Author(s):  
David M. Emms ◽  
Steven Kelly

AbstractHere, we present a major advance of the OrthoFinder method. This extends OrthoFinder’s high accuracy orthogroup inference to provide phylogenetic inference of orthologs, rooted gene trees, gene duplication events, the rooted species tree, and comparative genomics statistics. Each output is benchmarked on appropriate real or simulated datasets, and where comparable methods exist, OrthoFinder is equivalent to or outperforms these methods. Furthermore, OrthoFinder is the most accurate ortholog inference method on the Quest for Orthologs benchmark test. Finally, OrthoFinder’s comprehensive phylogenetic analysis is achieved with equivalent speed and scalability to the fastest, score-based heuristic methods. OrthoFinder is available at https://github.com/davidemms/OrthoFinder.


Genome ◽  
2004 ◽  
Vol 47 (6) ◽  
pp. 1082-1090 ◽  
Author(s):  
David M Irwin

Expansion of the lysozyme gene family is associated with the evolution of the ruminant lifestyle in ruminant artiodactyls such as the cow. Gene duplications allowed recombination between stomach lysozyme genes that may have assisted in the evolution of an enzyme adapted to survive and function in the stomach environment. Despite amplification of lysozyme genes, cow tears, milk, and blood are considered to be lysozyme deficient. Here we have identified 2 new cow lysozyme cDNA sequences and show that at least 4 different lysozymes are expressed in cows in nonstomach tissues and probably function as antibacterial defence enzymes. These 4 lysozyme genes are in addition to the 4 digestive lysozyme genes expressed in the stomach, yielding a number of expressed lysozyme genes in the cow larger than that found in most nonlysozyme-deficient mammals. In contrast to expectations, evidence for recombination between stomach and nonstomach lysozyme genes was found. Recombination, through concerted evolution, may have allowed some lysozymes to acquire the ability to survive in occasional acidic environments.Key words: molecular evolution, adaptive evolution, lysozyme, ruminants, gene duplication, gene evolution.


2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Yuwei Wang ◽  
Baocheng Guo

Abstract Background Gene duplication and alternative splicing (AS) are two distinct mechanisms generating new materials for genetic innovations. The evolutionary link between gene duplication and AS is still controversial, due to utilizing duplicates from inconsistent ages of duplication events in earlier studies. With the aid of RNA-seq data, we explored evolutionary scenario of AS divergence between duplicates with ohnologs that resulted from the teleost genome duplication event in zebrafish, medaka, and stickleback. Results Ohnologs in zebrafish have fewer AS forms compared to their singleton orthologs, supporting the function-sharing model of AS divergence between duplicates. Ohnologs in stickleback have more AS forms compared to their singleton orthologs, which supports the accelerated model of AS divergence between duplicates. The evolution of AS in ohnologs in medaka supports a combined scenario of the function-sharing and the accelerated model of AS divergence between duplicates. We also found a small number of ohnolog pairs in each of the three teleosts showed significantly asymmetric AS divergence. For example, the well-known ovary-factor gene cyp19a1a has no AS form but its ohnolog cyp19a1b has multiple AS forms in medaka, suggesting that functional divergence between duplicates might have result from AS divergence. Conclusions We found that a combined scenario of function-sharing and accelerated models for AS evolution in ohnologs in teleosts and rule out the independent model that assumes a lack of correlation between gene duplication and AS. Our study thus provided insights into the link between gene duplication and AS in general and ohnolog divergence in teleosts from AS perspective in particular.


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