scholarly journals Selective constraints on coding sequences of nervous system genes are a major determinant of duplicate gene retention in vertebrates

2016 ◽  
Author(s):  
Julien Roux ◽  
Jialin Liu ◽  
Marc Robinson-Rechavi
Keyword(s):  
Nervous System ◽  
Whole Genome Duplication ◽  
Genome Duplication ◽  
Expression Patterns ◽  
Enrichment Analysis ◽  
Duplicate Genes ◽  
Whole Genome ◽  
Coding Sequences ◽  
Whole Genome Duplications ◽  
Genome Duplications

AbstractThe evolutionary history of vertebrates is marked by three ancient whole-genome duplications: two successive rounds in the ancestor of vertebrates, and a third one specific to teleost fishes. Biased loss of most duplicates enriched the genome for specific genes, such as slow evolving genes, but this selective retention process is not well understood. To understand what drives the long-term preservation of duplicate genes, we characterized duplicated genes in terms of their expression patterns. We used a new method of expression enrichment analysis, TopAnat, applied to in situ hybridization data from thousands of genes from zebrafish and mouse. We showed that the presence of expression in the nervous system is a good predictor of a higher rate of retention of duplicate genes after whole-genome duplication. Further analyses suggest that purifying selection against the toxic effects of misfolded or misinteracting proteins, which is particularly strong in non-renewing neural tissues, likely constrains the evolution of coding sequences of nervous system genes, leading indirectly to the preservation of duplicate genes after whole-genome duplication. Whole-genome duplications thus greatly contributed to the expansion of the toolkit of genes available for the evolution of profound novelties of the nervous system at the base of the vertebrate radiation.

scholarly journals Genetic drift dominates genome-wide regulatory evolution following an ancient whole genome duplication in Atlantic salmon

2020 ◽  
Author(s):  
Jukka-Pekka Verta ◽  
Henry Barton ◽  
Victoria Pritchard ◽  
Craig Primmer
Keyword(s):  
Atlantic Salmon ◽  
Whole Genome Duplication ◽  
Genome Duplication ◽  
Regulatory Elements ◽  
Functional Redundancy ◽  
Neutral Evolution ◽  
Whole Genome ◽  
Regulatory Evolution ◽  
Whole Genome Duplications ◽  
Genome Duplications

AbstractWhole genome duplications (WGD) have been considered as springboards that potentiate lineage diversification through increasing functional redundancy. Divergence in gene regulatory elements is a central mechanism for evolutionary diversification, yet the patterns and processes governing regulatory divergence following events that lead to massive functional redundancy, such as WGD, remain largely unknown. We studied the patterns of divergence and strength of natural selection on regulatory elements in the Atlantic salmon (Salmo salar) genome, which has undergone WGD 100-80 Mya. Using ChIPmentation, we first show that H3K27ac, a histone modification typical to enhancers and promoters, is associated with genic regions, tissue specific transcription factor binding motifs, and with gene transcription levels in immature testes. Divergence in transcription between duplicated genes from WGD (ohnologs) correlated with difference in the number of proximal regulatory elements, but not with promoter elements, suggesting that functional divergence between ohnologs after WGD is mainly driven by enhancers. By comparing H3K27ac regions between duplicated genome blocks, we further show that a longer polyploid state post-WGD has constrained asymmetric regulatory evolution. Patterns of genetic diversity across natural populations inferred from re-sequencing indicate that recent evolutionary pressures on H3K27ac regions are dominated by largely neutral evolution. In sum, our results suggest that post-WGD functional redundancy in regulatory elements continues to have an impact on the evolution of the salmon genome, promoting largely neutral evolution of regulatory elements despite their association with transcription levels. These results highlight a case where genome-wide regulatory evolution following an ancient WGD is dominated by genetic drift.Significance statementRegulatory evolution following whole genome duplications (WGD) has been investigated at the gene expression level, but studies of the regulatory elements that control expression have been lacking. By investigating regulatory elements in the Atlantic salmon genome, which has undergone a whole genome duplication 100-80 million years ago, we discovered patterns suggesting that neutral divergence is the prevalent mode of regulatory element evolution post-WGD. Our results suggest mechanisms for explaining the prevalence of asymmetric gene expression evolution following whole genome duplication, as well as the mismatch between evolutionary rates in enhancers versus that of promoters.

scholarly journals Widespread retention of ohnologs in key developmental gene families following whole genome duplication in arachnopulmonates

2021 ◽  
Author(s):  
Amber Harper ◽  
Luis Baudouin Gonzalez ◽  
Anna Schönauer ◽  
Ralf Janssen ◽  
Michael Seiter ◽  
...  
Keyword(s):  
Whole Genome Duplication ◽  
Genome Duplication ◽  
Genetic Material ◽  
Gene Families ◽  
Comparative Approach ◽  
Whole Genome ◽  
Animal Evolution ◽  
Whole Genome Duplications ◽  
Genome Duplications ◽  
Horseshoe Crabs

Abstract Whole genome duplications have occurred multiple times during animal evolution, including in lineages leading to vertebrates, teleosts, horseshoe crabs and arachnopulmonates. These dramatic events initially produce a wealth of new genetic material, generally followed by extensive gene loss. It appears, however, that developmental genes such as homeobox genes, signalling pathway components and microRNAs are frequently retained as duplicates (so called ohnologs) following whole-genome duplication. These not only provide the best evidence for whole-genome duplication, but an opportunity to study its evolutionary consequences. Although these genes are well studied in the context of vertebrate whole-genome duplication, similar comparisons across the extant arachnopulmonate orders are patchy. We sequenced embryonic transcriptomes from two spider species and two amblypygid species and surveyed three important gene families, Hox, Wnt and frizzled, across these and twelve existing transcriptomic and genomic resources for chelicerates. We report extensive retention of putative ohnologs, further supporting the ancestral arachnopulmonate whole-genome duplication. We also found evidence of consistent evolutionary trajectories in Hox and Wnt gene repertoires across three of the six arachnopulmonate orders, with inter-order variation in the retention of specific paralogs. We identified variation between major clades in spiders and are better able to reconstruct the chronology of gene duplications and losses in spiders, amblypygids, and scorpions. These insights shed light on the evolution of the developmental toolkit in arachnopulmonates, highlight the importance of the comparative approach within lineages, and provide substantial new transcriptomic data for future study.

scholarly journals Genetic and Epigenetic Changes Are Rapid Responses of the Genome to the Newly Synthesized Autotetraploid Carassius auratus

2021 ◽  
Vol 11 ◽  
Author(s):  
Chongqing Wang ◽  
Yuwei Zhou ◽  
Huan Qin ◽  
Chun Zhao ◽  
Li Yang ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Carassius Auratus ◽  
Whole Genome Duplication ◽  
Genome Duplication ◽  
Enrichment Analysis ◽  
Full Length ◽  
Aflp Analysis ◽  
Whole Genome ◽  
Epigenetic Alterations ◽  
Fish Genome

Whole genome duplication events have occurred frequently during the course of vertebrate evolution. To better understand the influence of polyploidization on the fish genome, we herein used the autotetraploid Carassius auratus (4n = 200, RRRR) (4nRR) resulting from the whole genome duplication of Carassius auratus (2n = 100, RR) (RCC) to explore the genomic and epigenetic alterations after polyploidization. We subsequently performed analyses of full-length transcriptome dataset, amplified fragment length polymorphism (AFLP) and methylation sensitive amplification polymorphism (MSAP) on 4nRR and RCC. By matching the results of 4nRR and RCC isoforms with reference genome in full-length transcriptome dataset, 649 and 1,971 novel genes were found in the RCC and 4nRR full-length geneset, respectively. Compared to Carassius auratus and Megalobrama amblycephala, 4nRR presented 3,661 unexpressed genes and 2,743 expressed genes. Furthermore, GO enrichment analysis of expressed genes in 4nRR revealed that they were enriched in meiosis I, whereas KEGG enrichment analysis displayed that they were mainly enriched in proteasome. Using AFLP analysis, we noted that 32.61% of RCC fragments had disappeared, while 32.79% of new bands were uncovered in 4nRR. Concerning DNA methylation, 4nRR exhibited a lower level of global DNA methylation than RCC. Additionally, 60.31% of methylation patterns in 4nRR were altered compared to RCC. These observations indicated that transcriptome alterations, genomic changes and regulation of DNA methylation levels and patterns had occurred in the newly established autotetraploid genomes, suggesting that genetic and epigenetic alterations were influenced by autotetraploidization. In summary, this study provides valuable novel insights into vertebrate genome evolution and generates relevant information for fish breeding.

scholarly journals Excision Dominates Pseudogenization During Fractionation After Whole Genome Duplication and in Gene Loss After Speciation in Plants

2020 ◽  
Vol 11 ◽  
Author(s):  
Zhe Yu ◽  
Chunfang Zheng ◽  
Victor A. Albert ◽  
David Sankoff
Keyword(s):  
Whole Genome Duplication ◽  
Gene Loss ◽  
Genome Duplication ◽  
Duplicate Genes ◽  
Whole Genome ◽  
Coding Sequence ◽  
Genome Doubling ◽  
Whole Genome Doubling ◽  
Synteny Blocks ◽  
Genomic Divergence

We take advantage of synteny blocks, the analytical construct enabled at the evolutionary moment of speciation or polyploidization, to follow the independent loss of duplicate genes in two sister species or the loss through fractionation of syntenic paralogs in a doubled genome. By examining how much sequence remains after a contiguous series of genes is deleted, we find that this residue remains at a constant low level independent of how many genes are lost—there are few if any relics of the missing sequence. Pseudogenes are rare or extremely transient in this context. The potential exceptions lie exclusively with a few examples of speciation, where the synteny blocks in some larger genomes tolerate degenerate sequence during genomic divergence of two species, but not after whole genome doubling in the same species where fractionation pressure eliminates virtually all non-coding sequence.

scholarly journals OHNOLOGS v2: a comprehensive resource for the genes retained from whole genome duplication in vertebrates

2019 ◽  
Author(s):  
Param Priya Singh ◽  
Hervé Isambert
Keyword(s):  
Teleost Fish ◽  
Whole Genome Duplication ◽  
Genome Duplication ◽  
Genetic Diseases ◽  
Genomic Analysis ◽  
Biased Sampling ◽  
Whole Genome ◽  
Genome Duplications ◽  
Evolutionary Genomic ◽  
The Impact

Abstract All vertebrates including human have evolved from an ancestor that underwent two rounds of whole genome duplication (2R-WGD). In addition, teleost fish underwent an additional third round of genome duplication (3R-WGD). The genes retained from these genome duplications, so-called ohnologs, have been instrumental in the evolution of vertebrate complexity, development and susceptibility to genetic diseases. However, the identification of vertebrate ohnologs has been challenging, due to lineage specific genome rearrangements since 2R- and 3R-WGD. We previously identified vertebrate ohnologs using a novel synteny comparison across multiple genomes. Here, we refine and apply this approach on 27 vertebrate genomes to identify ohnologs from both 2R- and 3R-WGD, while taking into account the phylogenetically biased sampling of available species. We assemble vertebrate ohnolog pairs and families in an expanded OHNOLOGS v2 database. We find that teleost fish have retained more 2R-WGD ohnologs than mammals and sauropsids, and that these 2R-ohnologs have retained significantly more ohnologs from the subsequent 3R-WGD than genes without 2R-ohnologs. Interestingly, species with fewer extant genes, such as sauropsids, have retained similar or higher proportions of ohnologs. OHNOLOGS v2 should allow deeper evolutionary genomic analysis of the impact of WGD on vertebrates and can be freely accessed at http://ohnologs.curie.fr.

scholarly journals Fine-scale ecological and transcriptomic data reveal niche differentiation of an allopolyploid from diploid parents in Cardamine

2019 ◽  
Author(s):  
Reiko Akiyama ◽  
Jianqiang Sun ◽  
Masaomi Hatakeyama ◽  
Heidi E.L. Lischer ◽  
Roman V. Briskine ◽  
...  
Keyword(s):  
Water Availability ◽  
Whole Genome Duplication ◽  
Genome Duplication ◽  
Expression Patterns ◽  
Niche Differentiation ◽  
Gene Expression Patterns ◽  
Whole Genome ◽  
Fine Scale ◽  
Transcriptomic Data ◽  
Cardamine Flexuosa

AbstractPolyploidization, or whole genome duplication, is one of the major mechanisms of plant speciation. Allopolyploids (species that harbor polyploid genomes originating from hybridization of different diploid species) have been hypothesized to occupy a niche with intermediate, broader, or fluctuating environmental conditions compared with parental diploids. It remains unclear whether empirical data support this hypothesis and whether specialization of expression patterns of the homeologs (paralogous gene copies resulting from allopolyploidization) relates to habitat environments. Here, we studied the ecology and transcriptomics of a wild allopolyploid Cardamine flexuosa and its diploid parents C. hirsuta and C. amara at a fine geographical scale in their native area in Switzerland. We found that the diploid parents favored opposite extremes in terms of soil moisture, soil carbon-to-nitrogen ratios, and light availability. The habitat of the allopolyploid C. flexuosa was broader compared with those of its parental species and overlapped with those of the parents, but not at its extremes. In C. flexuosa, the genes related to water availability were overrepresented among those at both the expression level and the expression ratio of homeolog pairs, which varied among habitat environments. These findings provide empirical evidence for niche differentiation between an allopolyploid and its diploid parents at a fine scale, where both ecological and transcriptomic data indicated water availability to be the key environmental factor for niche differentiation.Significance statementPolyploidization, or whole genome duplication, is common in plants and may contribute to their ecological diversification. However, little is known about the niche differentiation of wild allopolyploids relative to their diploid parents and the gene expression patterns that may underlie such ecological divergence. We detected niche differentiation between the allopolyploid Cardamine flexuosa and its diploid parents C. amara and C. hirsuta along water availability gradient at a fine scale. The ecological differentiation was mirrored by the dynamic control of water availability-related gene expression patterns according to habitat environments. Thus, both ecological and transcriptomic data revealed niche differentiation between an allopolyploid species and its diploid parents.

scholarly journals Polyploidy and the Evolution of Complex Traits

2012 ◽  
Vol 2012 ◽  
pp. 1-12 ◽  
Author(s):  
Lukasz Huminiecki ◽  
Gavin C. Conant
Keyword(s):  
Complex Traits ◽  
Genome Duplication ◽  
Single Gene ◽  
Whole Genome ◽  
Gene Duplications ◽  
Evolutionary Potential ◽  
Evolutionary Transitions ◽  
Whole Genome Duplications ◽  
Genome Duplications ◽  
Modern Evolutionary Theory

We explore how whole-genome duplications (WGDs) may have given rise to complex innovations in cellular networks, innovations that could not have evolved through sequential single-gene duplications. We focus on two classical WGD events, one in bakers’ yeast and the other at the base of vertebrates (i.e., two rounds of whole-genome duplication: 2R-WGD). Two complex adaptations are discussed in detail: aerobic ethanol fermentation in yeast and the rewiring of the vertebrate developmental regulatory network through the 2R-WGD. These two examples, derived from diverged branches on the eukaryotic tree, boldly underline the evolutionary potential of WGD in facilitating major evolutionary transitions. We close by arguing that the evolutionary importance of WGD may require updating certain aspects of modern evolutionary theory, perhaps helping to synthesize a new evolutionary systems biology.

scholarly journals Differential retention and divergent resolution of duplicate genes following whole-genome duplication

2014 ◽  
Vol 24 (10) ◽  
pp. 1665-1675 ◽  
Author(s):  
Casey L. McGrath ◽  
Jean-Francois Gout ◽  
Parul Johri ◽  
Thomas G. Doak ◽  
Michael Lynch
Keyword(s):  
Whole Genome Duplication ◽  
Genome Duplication ◽  
Duplicate Genes ◽  
Whole Genome ◽  
Differential Retention

scholarly journals ksrates: positioning whole-genome duplications relative to speciation events using rate-adjusted mixed paralog–ortholog KS distributions

2021 ◽  
Author(s):  
Cecilia Sensalari ◽  
Steven Maere ◽  
Rolf Lohaus
Keyword(s):  
Open Source Software ◽  
Genome Duplication ◽  
Synonymous Substitution ◽  
Whole Genome ◽  
Substitution Rates ◽  
Whole Genome Duplications ◽  
Genome Duplications ◽  
Command Line Tool ◽  
Synonymous Substitution Rates ◽  
User Friendly

Summary: To position ancient whole-genome duplication (WGD) events with respect to speciation events in a phylogeny, the KS values of WGD paralog pairs in a species of interest are often compared with the KS values of ortholog pairs between this species and other species. However, if the lineages involved exhibit different substitution rates, direct comparison of paralog and ortholog KS estimates can be misleading and result in phylogenetic misinterpretation of WGD signatures. Here we present ksrates, a user-friendly command-line tool to compare paralog and ortholog KS distributions derived from genomic or transcriptomic sequences. ksrates estimates differences in synonymous substitution rates among the lineages involved and generates an adjusted mixed plot of paralog and ortholog KS distributions that allows to assess the relative phylogenetic positioning of presumed WGD and speciation events. Availability and implementation: ksrates is open-source software implemented in Python 3 and as a Nextflow pipeline. The source code, Singularity and Docker containers, documentation and tutorial are available via https://github.com/VIB-PSB/ksrates.

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