scholarly journals Gene and Genome Duplication in Acanthamoeba polyphaga Mimivirus

2005 ◽  
Vol 79 (22) ◽  
pp. 14095-14101 ◽  
Author(s):  
Karsten Suhre

ABSTRACT Gene duplication is key to molecular evolution in all three domains of life and may be the first step in the emergence of new gene function. It is a well-recognized feature in large DNA viruses but has not been studied extensively in the largest known virus to date, the recently discovered Acanthamoeba polyphaga Mimivirus. Here, I present a systematic analysis of gene and genome duplication events in the mimivirus genome. I found that one-third of the mimivirus genes are related to at least one other gene in the mimivirus genome, either through a large segmental genome duplication event that occurred in the more remote past or through more recent gene duplication events, which often occur in tandem. This shows that gene and genome duplication played a major role in shaping the mimivirus genome. Using multiple alignments, together with remote-homology detection methods based on Hidden Markov Model comparison, I assign putative functions to some of the paralogous gene families. I suggest that a large part of the duplicated mimivirus gene families are likely to interfere with important host cell processes, such as transcription control, protein degradation, and cell regulatory processes. My findings support the view that large DNA viruses are complex evolving organisms, possibly deeply rooted within the tree of life, and oppose the paradigm that viral evolution is dominated by lateral gene acquisition, at least in regard to large DNA viruses.

2001 ◽  
Vol 11 (5) ◽  
pp. 771-780 ◽  
Author(s):  
Austin L. Hughes ◽  
Jack da Silva ◽  
Robert Friedman

The fact that there are four homeobox (Hox) clusters in most vertebrates but only one in invertebrates is often cited as evidence for the hypothesis that two rounds of genome duplication by polyploidization occurred early in vertebrate history. In addition, it has been observed in humans and other mammals that numerous gene families include paralogs on two or more of the fourHox-bearing chromosomes (the chromosomes bearing theHox clusters; i.e., human chromosomes 2, 7, 12, and 17), and the existence of these paralogs has been taken as evidence that these genes were duplicated along with the Hox clusters by polyploidization. We tested this hypothesis by phylogenetic analysis of 42 gene families including members on two or more of the humanHox-bearing chromosomes. In 32 of these families there was evidence against the hypothesis that gene duplication occurred simultaneously with duplication of the Hox clusters. Phylogenies of 14 families supported the occurrence of one or more gene duplications before the origin of vertebrates, and of 15 gene duplication times estimated for gene families evolving in a clock-like manner, only six were dated to the same time period early in vertebrate history during which the Hox clusters duplicated. Furthermore, of gene families duplicated around the same time as the Hoxclusters, the majority showed topologies inconsistent with their having duplicated simultaneously with the Hox clusters. The results thus indicate that ancient events of genome duplication, if they occurred at all, did not play an important role in structuring the mammalian Hox-bearing chromosomes.


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.


Development ◽  
1994 ◽  
Vol 1994 (Supplement) ◽  
pp. 125-133 ◽  
Author(s):  
Peter W. H. Holland ◽  
Jordi Garcia-Fernàndez ◽  
Nic A. Williams ◽  
Arend Sidow

All vertebrates possess anatomical features not seen in their closest living relatives, the protochordates (tunicates and amphioxus). Some of these features depend on developmental processes or cellular behaviours that are again unique to vertebrates. We are interested in the genetic changes that may have permitted the origin of these innovations. Gene duplication, followed by functional divergence of new genes, may be one class of mutation that permits major evolutionary change. Here we examine the hypothesis that gene duplication events occurred close to the origin and early radiation of the vertebrates. Genome size comparisons are compatible with the occurrence of duplications close to vertebrate origins; more precise insight comes from cloning and phylogenetic analysis of gene families from amphioxus, tunicates and vertebrates. Comparisons of Hox gene clusters, other homeobox gene families, Wnt genes and insulin-related genes all indicate that there was a major phase of gene duplication close to vertebrate origins, after divergence from the amphioxus lineage; we suggest there was probably a second phase of duplication close to jawed vertebrate origins. From amphioxus and vertebrate homeobox gene expression patterns, we suggest that there are multiple routes by which new genes arising from gene duplication acquire new functions and permit the evolution of developmental innovations.


2018 ◽  
Vol 12 (2) ◽  
pp. 119
Author(s):  
Puji Lestari ◽  
Suk-Ha Lee ◽  
I Made Tasma ◽  
Asadi Asadi

<p><strong>Gene duplication to reveal adaptation </strong><strong>clue</strong><strong> of plant to environmental stress: A case study of NBS-LRR genes in soybean. <em>Puji Lestari, Suk-Ha Lee</em></strong><strong><em>, I Made Tasma</em></strong><strong><em>, </em></strong><strong><em>and </em></strong><strong><em>Asadi</em></strong><strong>. </strong>Adaptive strategies of plant to stress are fine-tuned by adjusting several activities including molecular mechanism which involve duplicated genes responsive to environmental changes. Genes responsive to the environmental stresses which are retained after small scale duplication are part of plant genome duplication. However, less information of duplicated genes could be adaptive to environmental changes in plant. This review presents an overview of duplication events in plant genomes which impact to gene duplication in relation to environmental changes, gene duplication as an adaptation mechanism, a case of duplicated nucleotide binding site-<em>leucine</em>-<em>rich</em> repeat (NBS-LRR) genes in soybean, and the gene duplication implementation for plant breeding in Indonesia. Notably, genome duplication events generate gene duplication and contribute to adaptive evolution against environmental changes. Generalization of plants to adapt the stressful conditions also probably improves our understanding of gene duplication as a mechanism of adaptation. Several recently duplicated NBS-LRR genes in soybean retain disease resistance QTL and the differential expression convince their contribution to biotic stress resistance in soybean. Proposed models of NBS-LRR genes duplication process may help to understand these genes response to the environmental changes. The duplication of genes resistant to pest/disease particularly NBS-LRR provides important information to select breeding parents and develop molecular markers related to desease resistance to genetically improve soybean in Indonesia. Overall, it may therefore be possible to enhance breeding which targets on genes tolerance/resistance to abiotic/biotic stress, and provide a molecular basis for crop-stress protection strategy and more improved soybean varieties specified for harsh environment.</p>


2021 ◽  
Author(s):  
Tzachi Hagai ◽  
Evgeny Fraimovitch

Gene duplication is thought to be a central mechanism in evolution to gain new functions, but gene families vary greatly in their rates of gene duplication and long-term retention. Here, we discover a link between the promoter architecture of vertebrate genes and their rate of duplication: Genes that harbor CpG Islands in their promoters (CGI genes) - nearly 60% of our genes - have rarely duplicated in recent evolutionary times, and most CGI gene duplication events predate the emergence of CGI as a major regulatory element of vertebrate genes. In contrast, CGI-less genes predominate duplications that have occurred since the divergence of vertebrates. Furthermore, CGI-less paralogs are transcriptionally more divergent than CGI paralogs, even when comparing CGI and CGI-less paralogs that have duplicated at similar evolutionary times - suggesting greater capacity of CGI-less promoters to enable divergence in expression. This higher divergence between CGI-less paralogs is also reflected in lower similarity of transcription factors that bind to the promoters of CGI-less paralog pairs in comparison with CGI paralogs. Finally, CGI-less paralogs have a greater tendency to sub- and neo-functionalize, and they transcriptionally diversify faster following duplication. Our results highlight the links between promoter architecture, gene expression plasticity and their impact on gene expansion, and unravel an unappreciated role of CGI elements in shaping genome evolution.


2017 ◽  
Vol 284 (1858) ◽  
pp. 20170912 ◽  
Author(s):  
James W. Clark ◽  
Philip C. J. Donoghue

Whole genome duplication (WGD) has occurred in many lineages within the tree of life and is invariably invoked as causal to evolutionary innovation, increased diversity, and extinction resistance. Testing such hypotheses is problematic, not least since the timing of WGD events has proven hard to constrain. Here we show that WGD events can be dated through molecular clock analysis of concatenated gene families, calibrated using fossil evidence for the ages of species divergences that bracket WGD events. We apply this approach to dating the two major genome duplication events shared by all seed plants ( ζ ) and flowering plants ( ɛ ), estimating the seed plant WGD event at 399–381 Ma, and the angiosperm WGD event at 319–297 Ma. These events thus took place early in the stem of both lineages, precluding hypotheses of WGD conferring extinction resistance, driving dramatic increases in innovation and diversity, but corroborating and qualifying the more permissive hypothesis of a ‘lag-time’ in realizing the effects of WGD in plant evolution.


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