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

Author(s):  
Jukka-Pekka Verta ◽  
Henry J Barton ◽  
Victoria Pritchard ◽  
Craig R Primmer

Abstract Whole 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 regulatory divergence. 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.

2020 ◽  
Author(s):  
Jukka-Pekka Verta ◽  
Henry Barton ◽  
Victoria Pritchard ◽  
Craig Primmer

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.


2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Zhixuan Du ◽  
Qitao Su ◽  
Zheng Wu ◽  
Zhou Huang ◽  
Jianzhong Bao ◽  
...  

AbstractMultidrug and toxic compound extrusion (MATE) proteins are involved in many physiological functions of plant growth and development. Although an increasing number of MATE proteins have been identified, the understanding of MATE proteins is still very limited in rice. In this study, 46 MATE proteins were identified from the rice (Oryza sativa) genome by homology searches and domain prediction. The rice MATE family was divided into four subfamilies based on the phylogenetic tree. Tandem repeats and fragment replication contribute to the expansion of the rice MATE gene family. Gene structure and cis-regulatory elements reveal the potential functions of MATE genes. Analysis of gene expression showed that most of MATE genes were constitutively expressed and the expression patterns of genes in different tissues were analyzed using RNA-seq. Furthermore, qRT-PCR-based analysis showed differential expression patterns in response to salt and drought stress. The analysis results of this study provide comprehensive information on the MATE gene family in rice and will aid in understanding the functional divergence of MATE genes.


2020 ◽  
Vol 21 (17) ◽  
pp. 5947 ◽  
Author(s):  
Hao Zhang ◽  
Shuang Li ◽  
Mengyao Shi ◽  
Sheliang Wang ◽  
Lei Shi ◽  
...  

NITRATE TRANSPORTER 1 (NRT1)/PEPTIDE TRANSPORTER (PTR) family (NPF) proteins can transport various substrates, and play crucial roles in governing plant nitrogen (N) uptake and distribution. However, little is known about the NPF genes in Brassica napus. Here, a comprehensive genome-wide systematic characterization of the NPF family led to the identification of 193 NPF genes in the whole genome of B. napus. The BnaNPF family exhibited high levels of genetic diversity among sub-families but this was conserved within each subfamily. Whole-genome duplication and segmental duplication played a major role in BnaNPF evolution. The expression analysis indicated that a broad range of expression patterns for individual gene occurred in response to multiple nutrient stresses, including N, phosphorus (P) and potassium (K) deficiencies, as well as ammonium toxicity. Furthermore, 10 core BnaNPF genes in response to N stress were identified. These genes contained 6–13 transmembrane domains, located in plasma membrane, that respond discrepantly to N deficiency in different tissues. Robust cis-regulatory elements were identified within the promoter regions of the core genes. Taken together, our results suggest that BnaNPFs are versatile transporters that might evolve new functions in B. napus. Our findings benefit future research on this gene family.


2021 ◽  
Author(s):  
Marsha M. Wheeler ◽  
Adrienne M Stilp ◽  
Shuquan Rao ◽  
Bjarni V Halldorsson ◽  
Doruk V Beyter ◽  
...  

Genome-wide association studies (GWAS) have identified thousands of single nucleotide variants and small indels that contribute to the genetic architecture of hematologic traits. While structural variants (SVs) are known to cause rare blood or hematopoietic disorders, the genome-wide contribution of SVs to quantitative blood cell trait variation is unknown. Here we utilized SVs detected from whole genome sequencing (WGS) in ancestrally diverse participants of the NHLBI TOPMed program (N=50,675). Using single variant tests, we assessed the association of common and rare SVs with red cell-, white cell-, and platelet-related quantitative traits. The results show 33 independent SVs (23 common and 10 rare) reaching genome-wide significance. The majority of significant association signals (N=27) replicated in independent datasets from deCODE genetics and the UK BioBank. Moreover, most trait-associated SVs (N=24) are within 1Mb of previously-reported GWAS loci. SV analyses additionally discovered an association between a complex structural variant on 17p11.2 and white blood cell-related phenotypes. Based on functional annotation, the majority of significant SVs are located in non-coding regions (N=26) and predicted to impact regulatory elements and/or local chromatin domain boundaries in blood cells. We predict that several trait-associated SVs represent the causal variant. This is supported by genome-editing experiments which provide evidence that a deletion associated with lower monocyte counts leads to disruption of an S1PR3 monocyte enhancer and decreased S1PR3 expression.


2014 ◽  
Author(s):  
Adam Siepel ◽  
Leonardo Arbiza

Modification of gene regulation has long been considered an important force in human evolution, particularly through changes to cis-regulatory elements (CREs) that function in transcriptional regulation. For decades, however, the study of cis-regulatory evolution was severely limited by the available data. New data sets describing the locations of CREs and genetic variation within and between species have now made it possible to study CRE evolution much more directly on a genome-wide scale. Here, we review recent research on the evolution of CREs in humans based on large-scale genomic data sets. We consider inferences based on primate divergence,human polymorphism, and combinations of divergence and polymorphism. We then consider "new frontiers" in this field stemming from recent research on transcriptional regulation.


2017 ◽  
Author(s):  
Fiona M. Robertson ◽  
Manu Kumar Gundappa ◽  
Fabian Grammes ◽  
Torgeir R. Hvidsten ◽  
Anthony K. Redmond ◽  
...  

AbstractThe functional divergence of duplicate genes (ohnologues) retained from whole genome duplication (WGD) is thought to promote evolutionary diversification. However, species radiation and phenotypic diversification is often highly temporally-detached from WGD. Salmonid fish, whose ancestor experienced WGD by autotetraploidization ~95 Ma (i.e. ‘Ss4R’), fit such a ‘time-lag’ model of post-WGD radiation, which occurred alongside a major delay in the rediploidization process. Here we propose a model called ‘Lineage-specific Ohnologue Resolution’ (LORe) to address the phylogenetic and functional consequences of delayed rediploidization. Under LORe, speciation precedes rediploidization, allowing independent ohnologue divergence in sister lineages sharing an ancestral WGD event. Using cross-species sequence capture, phylogenomics and genome-wide analyses of ohnologue expression divergence, we demonstrate the major impact of LORe on salmonid evolution. One quarter of each salmonid genome, harbouring at least 4,500 ohnologues, has evolved under LORe, with rediploidization and functional divergence occurring on multiple independent occasions > 50 Myr post-WGD. We demonstrate the existence and regulatory divergence of many LORe ohnologues with functions in lineage-specific physiological adaptations that promoted salmonid species radiation. We show that LORe ohnologues are enriched for different functions than ‘older’ ohnologues that began diverging in the salmonid ancestor. LORe has unappreciated significance as a nested component of post-WGD divergence that impacts the functional properties of genes, whilst providing ohnologues available solely for lineage-specific adaptation. Under LORe, which is predicted following many WGD events, the functional outcomes of WGD need not appear ‘explosively’, but can arise gradually over tens of Myr, promoting lineage-specific diversification regimes under prevailing ecological pressures.


2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Ying Bao ◽  
Guanjing Hu ◽  
Corrinne E. Grover ◽  
Justin Conover ◽  
Daojun Yuan ◽  
...  

AbstractCis and trans regulatory divergence underlies phenotypic and evolutionary diversification. Relatively little is understood about the complexity of regulatory evolution accompanying crop domestication, particularly for polyploid plants. Here, we compare the fiber transcriptomes between wild and domesticated cotton (Gossypium hirsutum) and their reciprocal F1 hybrids, revealing genome-wide (~15%) and often compensatory cis and trans regulatory changes under divergence and domestication. The high level of trans evolution (54%–64%) observed is likely enabled by genomic redundancy following polyploidy. Our results reveal that regulatory variation is significantly associated with sequence evolution, inheritance of parental expression patterns, co-expression gene network properties, and genomic loci responsible for domestication traits. With respect to regulatory evolution, the two subgenomes of allotetraploid cotton are often uncoupled. Overall, our work underscores the complexity of regulatory evolution during fiber domestication and may facilitate new approaches for improving cotton and other polyploid plants.


2019 ◽  
Vol 9 (1) ◽  
pp. 9-16
Author(s):  
Константин Крутовский ◽  
Konstantin Krutovskiy ◽  
Юлия Путинцева ◽  
Yuliya Putinceva ◽  
Наталья Орешкова ◽  
...  

The forest genetics, tree improvement and protection can greatly benefit from complete genome sequence data made recently available for several major conifer species. They allow to identify and annotate genes, other functional elements (sRNA, transcription factors, regulatory elements, etc.) and genetic networks that control adaptation and dis-ease resistance. They can be used to develop highly informative genetic markers that can be used in population genetic studies to create database of barcodes for individual populations to fight illegal timber harvest and trade. They are very much needed for development of genome-wide genetic markers for association studies for linking genetic variation (SNPs, alleles, haplotypes, and genotypes) with environmental factors, adaptive traits and phenotypes for better understanding genetic control of agronomically and economically important traits. They can be also used to develop genome-wide genetic markers for genomic-assisted selection to breed for better adapted, stress resistant and climate change resilient trees with desirable quality ecological and economic traits. Finally, whole genome sequences allow to integrate proteomics, transcriptomics and metabolomics and provide reference genomes for resequencing. In this brief summary we would like to present one of many practical applications of genetics and genomics in forestry– development of highly polymorphic and informative molecular genetic markers for several very important boreal for-est species in Eurasia, Siberian larch (Larix sibirica Ledeb.), Siberian stone pine (Pinus sibirica Du Tour) and Scots pine (Pinus sylvestris L.), based on the whole genome data obtained in the “Genomics of the Key Boreal Forest Conifer Species and Their Major Phytopathogens in the Russian Federation” project funded by the Government of the Russian Federation (grant no. 14.Y26.31.0004).


Author(s):  
Yanrong Ji ◽  
Zhihan Zhou ◽  
Han Liu ◽  
Ramana V Davuluri

Abstract Motivation Deciphering the language of non-coding DNA is one of the fundamental problems in genome research. Gene regulatory code is highly complex due to the existence of polysemy and distant semantic relationship, which previous informatics methods often fail to capture especially in data-scarce scenarios. Results To address this challenge, we developed a novel pre-trained bidirectional encoder representation, named DNABERT, to capture global and transferrable understanding of genomic DNA sequences based on up and downstream nucleotide contexts. We compared DNABERT to the most widely used programs for genome-wide regulatory elements prediction and demonstrate its ease of use, accuracy and efficiency. We show that the single pre-trained transformers model can simultaneously achieve state-of-the-art performance on prediction of promoters, splice sites and transcription factor binding sites, after easy fine-tuning using small task-specific labeled data. Further, DNABERT enables direct visualization of nucleotide-level importance and semantic relationship within input sequences for better interpretability and accurate identification of conserved sequence motifs and functional genetic variant candidates. Finally, we demonstrate that pre-trained DNABERT with human genome can even be readily applied to other organisms with exceptional performance. We anticipate that the pre-trained DNABERT model can be fined tuned to many other sequence analyses tasks. Availability and implementation The source code, pretrained and finetuned model for DNABERT are available at GitHub (https://github.com/jerryji1993/DNABERT). Supplementary information Supplementary data are available at Bioinformatics online.


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