scholarly journals Large genetic diversity and strong positive selection in F-box and GPCR genes among the wild isolates of Caenorhabditis elegans

2020 ◽  
Author(s):  
Fuqiang Ma ◽  
Chun Yin Lau ◽  
Chaogu Zheng
Keyword(s):  
Population Structure ◽  
Gene Flow ◽  
Caenorhabditis Elegans ◽  
Positive Selection ◽  
Recombination Rate ◽  
Selective Sweep ◽  
Gene Families ◽  
Strong Positive Selection ◽  
High Recombination Rate ◽  
C Elegans

AbstractThe F-box and chemosensory GPCR (csGPCR) gene families are greatly expanded in nematodes, including the model organism Caenorhabditis elegans, compared to insects and vertebrates. However, the intraspecific evolution of these two gene families in nematodes remain unexamined. In this study, we analyzed the genomic sequences of 330 recently sequenced wild isolates of C. elegans using a range of population genetics approaches. We found that F-box and csGPCR genes, especially the Srw family csGPCRs, showed much more diversity than other gene families. Population structure analysis and phylogenetic analysis divided the wild strains into eight non-Hawaiian and three Hawaiian subpopulations. Some Hawaiian strains appeared to be more ancestral than all other strains. F-box and csGPCR genes maintained a great amount of the ancestral variants in the Hawaiian subpopulation and their divergence among the non-Hawaiian subpopulations contributed significantly to population structure. These genes are mostly located at the chromosomal arms and high recombination rate correlates with their large polymorphism. Gene flow might also contribute to their diversity. Moreover, we identified signatures of strong positive selection in the F-box and csGPCR genes in the non-Hawaiian population using both neutrality tests and Extended Haplotype Homozygosity analysis. Accumulation of high frequency derived alleles in these genes were found in non-Hawaiian population, leading to divergence from the ancestral genotype found in Hawaiian strains. In summary, we found that F-box and csGPCR genes harbour a large pool of natural variants, which may be subjected to positive selection during the recent selective sweep in non-Hawaiian population. These variants are mostly mapped to the substrate-recognition domains of F-box proteins and the extracellular regions of csGPCRs, possibly resulting in advantages during adaptation by affecting protein degradation and the sensing of environmental cues, respectively.Significance statementThe small nematode Caenorhabditis elegans has emerged as an important organism in studying the genetic mechanisms of evolution. F-box and chemosensory GPCR are two of the largest gene families in C. elegans, but their intraspecific evolution within C. elegans was not studied before. In this work, using the nonsynonymous SNV data of 330 C. elegans wild isolates, we found that F-box and chemosensory GPCR genes showed larger polymorphisms and stronger positive selection than other genes. The large diversity is likely the result of rapid gene family expansion, high recombination rate, and gene flow. Analysis of subpopulation suggests that positive selection of these genes occurred most strongly in the non-Hawaiian population, which underwent a selective sweep possibly linked to human activities.

scholarly journals Large genetic diversity and strong positive selection in F-box and GPCR genes among the wild isolates of Caenorhabditis elegans

2021 ◽  
Author(s):  
Fuqiang Ma ◽  
Chun Yin Lau ◽  
Chaogu Zheng
Keyword(s):  
Population Structure ◽  
Caenorhabditis Elegans ◽  
Positive Selection ◽  
Model Organism ◽  
Gene Families ◽  
Extended Haplotype ◽  
Strong Positive Selection ◽  
C Elegans ◽  
Population Structure Analysis ◽  
Wild Strains

Abstract The F-box and chemosensory GPCR (csGPCR) gene families are greatly expanded in nematodes, including the model organism Caenorhabditis elegans, compared to insects and vertebrates. However, the intraspecific evolution of these two gene families in nematodes remain unexamined. In this study, we analyzed the genomic sequences of 330 recently sequenced wild isolates of C. elegans using a range of population genetics approaches. We found that F-box and csGPCR genes, especially the Srw family csGPCRs, showed much more diversity than other gene families. Population structure analysis and phylogenetic analysis divided the wild strains into eight non-Hawaiian and three Hawaiian subpopulations. Some Hawaiian strains appeared to be more ancestral than all other strains. F-box and csGPCR genes maintained a great amount of the ancestral variants in the Hawaiian subpopulation and their divergence among the non-Hawaiian subpopulations contributed significantly to population structure. F-box genes are mostly located at the chromosomal arms and high recombination rate correlates with their large polymorphism. Moreover, using both neutrality tests and Extended Haplotype Homozygosity analysis, we identified signatures of strong positive selection in the F-box and csGPCR genes among the wild isolates, especially in the non-Hawaiian population. Accumulation of high-frequency derived alleles in these genes was found in non-Hawaiian population, leading to divergence from the ancestral genotype. In summary, we found that F-box and csGPCR genes harbour a large pool of natural variants, which may be subjected to positive selection. These variants are mostly mapped to the substrate-recognition domains of F-box proteins and the extracellular and intracellular regions of csGPCRs, possibly resulting in advantages during adaptation by affecting protein degradation and the sensing of environmental cues, respectively.

scholarly journals High-throughput transcriptome sequencing reveals extremely high doses of ionizing radiation-response genes in Caenorhabditis elegans

2019 ◽  
Vol 8 (5) ◽  
pp. 754-766 ◽  
Author(s):  
Youqin Xu ◽  
Lina Chen ◽  
Mengyi Liu ◽  
Yanfang Lu ◽  
Yanwei Yue ◽  
...  
Keyword(s):  
Caenorhabditis Elegans ◽  
Ionizing Radiation ◽  
Differential Expression ◽  
Gene Families ◽  
Rna Degradation ◽  
Cellular Growth ◽  
Radiation Response ◽  
Signalling Pathways ◽  
C Elegans ◽  
High Doses

Abstract This study sought novel ionizing radiation-response (IR-response) genes in Caenorhabditis elegans (C. elegans). C. elegans was divided into three groups and exposed to different high doses of IR: 0 gray (Gy), 200 Gy, and 400 Gy. Total RNA was extracted from each group and sequenced. When the transcriptomes were compared among these groups, many genes were shown to be differentially expressed, and these genes were significantly enriched in IR-related biological processes and pathways, including gene ontology (GO) terms related to cellular behaviours, cellular growth and purine metabolism and kyoto encyclopedia of genes and genomes (KEGG) pathways related to ATP binding, GTPase regulator activity, and RNA degradation. Quantitative reverse-transcription PCR (qRT-PCR) confirmed that these genes displayed differential expression across the treatments. Further gene network analysis showed a cluster of novel gene families, such as the guanylate cyclase (GCY), Sm-like protein (LSM), diacylglycerol kinase (DGK), skp1-related protein (SKR), and glutathione S-transferase (GST) gene families which were upregulated. Thus, these genes likely play important roles in IR response. Meanwhile, some important genes that are well known to be involved in key signalling pathways, such as phosphoinositide-specific phospholipase C-3 (PLC-3), phosphatidylinositol 3-kinase age-1 (AGE-1), Raf homolog serine/threonine-protein kinase (LIN-45) and protein cbp-1 (CBP-1), also showed differential expression during IR response, suggesting that IR response might perturb these key signalling pathways. Our study revealed a series of novel IR-response genes in Caenorhabditis elegans that might act as regulators of IR response and represent promising markers of IR exposure.

scholarly journals Meiotic recombination, noncoding DNA and genomic organization in Caenorhabditis elegans.

Genetics ◽  
1995 ◽  
Vol 141 (1) ◽  
pp. 159-179 ◽  
Author(s):  
T M Barnes ◽  
Y Kohara ◽  
A Coulson ◽  
S Hekimi
Keyword(s):  
Caenorhabditis Elegans ◽  
Genetic Map ◽  
Recombination Rate ◽  
Physical Map ◽  
Gene Density ◽  
Cdna Clones ◽  
Recombination Rates ◽  
Noncoding Dna ◽  
Physical Size ◽  
C Elegans

Abstract The genetic map of each Caenorhabditis elegans chromosome has a central gene cluster (less pronounced on the X chromosome) that contains most of the mutationally defined genes. Many linkage group termini also have clusters, though involving fewer loci. We examine the factors shaping the genetic map by analyzing the rate of recombination and gene density across the genome using the positions of cloned genes and random cDNA clones from the physical map. Each chromosome has a central gene-dense region (more diffuse on the X) with discrete boundaries, flanked by gene-poor regions. Only autosomes have reduced rates of recombination in these gene-dense regions. Cluster boundaries appear discrete also by recombination rate, and the boundaries defined by recombination rate and gene density mostly, but not always, coincide. Terminal clusters have greater gene densities than the adjoining arm but similar recombination rates. Thus, unlike in other species, most exchange in C. elegans occurs in gene-poor regions. The recombination rate across each cluster is constant and similar; and cluster size and gene number per chromosome are independent of the physical size of chromosomes. We propose a model of how this genome organization arose.

nos-1 and nos-2, two genes related to Drosophila nanos, regulate primordial germ cell development and survival in Caenorhabditis elegans

Development ◽  
1999 ◽  
Vol 126 (21) ◽  
pp. 4861-4871 ◽  
Author(s):  
K. Subramaniam ◽  
G. Seydoux
Keyword(s):  
Caenorhabditis Elegans ◽  
Germ Cell ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Primordial Germ Cell ◽  
Gene Families ◽  
Cell Development ◽  
Embryonic Patterning ◽  
Germ Cell Development ◽  
C Elegans

In Drosophila, the posterior determinant nanos is required for embryonic patterning and for primordial germ cell (PGC) development. We have identified three genes in Caenorhabditis elegans that contain a putative zinc-binding domain similar to the one found in nanos, and show that two of these genes function during PGC development. Like Drosophila nanos, C. elegans nos-1 and nos-2 are not generally required for PGC fate specification, but instead regulate specific aspects of PGC development. nos-2 is expressed in PGCs around the time of gastrulation from a maternal RNA associated with P granules, and is required for the efficient incorporation of PGCs into the somatic gonad. nos-1 is expressed in PGCs after gastrulation, and is required redundantly with nos-2 to prevent PGCs from dividing in starved animals and to maintain germ cell viability during larval development. In the absence of nos-1 and nos-2, germ cells cease proliferation at the end of the second larval stage, and die in a manner that is partially dependent on the apoptosis gene ced-4. Our results also indicate that putative RNA-binding proteins related to Drosophila Pumilio are required for the same PGC processes as nos-1 and nos-2. These studies demonstrate that evolutionarily distant organisms utilize conserved factors to regulate early germ cell development and survival, and that these factors include members of the nanos and pumilio gene families.

scholarly journals Global dissection of the BAHD acyltransferase gene family in soybean: Expression profiling, metabolic functions, and evolution

2020 ◽  
Author(s):  
Muhammad Zulfiqar Ahmad ◽  
Xiangsheng Zeng ◽  
Qiang Dong ◽  
Sehrish Manan ◽  
Huanan Jin ◽  
...  
Keyword(s):  
Positive Selection ◽  
Gene Family ◽  
Expression Profiles ◽  
Plant Defence ◽  
Constitutive Expression ◽  
Gene Families ◽  
Strong Positive Selection ◽  
Genome Wide ◽  
A Genome ◽  
Bahd Acyltransferase

Abstract Background: Members of the BAHD acyltransferase (ACT) family play important roles in plant defence against biotic and abiotic stresses. Previous genome-wide studies explored different acyltransferase gene families, but not a single study was found so far on the overall genome-wide or positive selection analyses of the BAHD family genes in Glycine max . A better understanding of the functions that specific members of this family play in stress defence can lead to better breeding strategies for stress tolerance. Results: A total of 103 genes of the BAHD family (GmACT genes) were mined from the soybean genome, which could be grouped into four phylogenetic clades (I- IV). Clade III was further divided into two sub-clades (IIIA and IIIB). In each clade, the constituent part of the gene structures and motifs were relatively conserved. These 103 genes were distributed unequally on all 20 chromosomes, and 16 paralogous pairs were found within the family. Positive selection analysis revealed important amino acids under strong positive selection, which suggests that the evolution of this gene family modulated soybean domestication. Most of the expression of ACT genes in soybean was repressed with Al 3+ and fungal elicitor exposure, except for GmACT84 , which expression increased in these conditions 2- and 3-fold, respectively. The promoter region of GmACT84 contains the maximum number of stress-responsive elements among all GmACT genes and is especially enriched in MYB-related elements. Some GmACT genes showed expression specific under specific conditions, while others showed constitutive expression in all soybean tissues or conditions analysed. Conclusions: This study provided a genome-wide analysis of the BAHD gene family and assessed their expression profiles. We found evidence of a strong positive selection of GmACT genes. Our findings will help efforts of functional characterisation of ACT genes in soybean in order to discover their involvement in growth, development, and defence mechanisms.

scholarly journals FUSTr: a tool to find gene Families Under Selection in Transcriptomes

2017 ◽  
Author(s):  
T. Jeffrey Cole ◽  
Michael S. Brewer
Keyword(s):  
Positive Selection ◽  
High Performance ◽  
Simulated Data ◽  
Gene Families ◽  
Coding Sequences ◽  
Strong Positive Selection ◽  
Link Type ◽  
Spider Toxin ◽  
Downstream Analysis

AbstractFUSTr is a tool for finding genes in transcriptomic datasets under strong positive selection that automatically detects isoform designation patterns in transcriptome assemblies to maximize phylogenetic independence in downstream analysis. When applied to previously studied spider toxin families as well as simulated data, FUSTr successfully grouped coding sequences into proper gene families as well as correctly identified those under strong positive selection. FUSTr provides a tool capable of utilizing multi-processor high-performance computational facilities and is scalable for large transcriptomic biodiversity datasets.AvailabilityFUSTr is freely available under a GNU license and can be downloaded at https://github.com/tijeco/[email protected]

scholarly journals Genetic analysis of Caenorhabditis elegans pry-1/Axin suppressors identifies genes involved in reproductive structure development, stress response, and aging

2021 ◽  
Author(s):  
Avijit Mallick ◽  
Nikita Jhaveri ◽  
Jihae Jeon ◽  
Yvonne Chang ◽  
Krupali Shah ◽  
...  
Keyword(s):  
Caenorhabditis Elegans ◽  
Stress Response ◽  
Genetic Interaction ◽  
Gene Families ◽  
Genetic Network ◽  
Reproductive Structure ◽  
Structure Development ◽  
C Elegans ◽  
Disease States ◽  
Genetic Epistasis

The Axin family of scaffolding proteins regulates a wide array of developmental and post-developmental processes in eukaryotes. Studies in the nematode, Caenorhabditis elegans, have shown that the Axin homolog, PRY-1, plays essential roles in multiple tissues. To understand the genetic network of pry-1, we focused on a set of genes that are differentially expressed in the pry-1-mutant transcriptome and are linked to reproductive structure development. Eight of the genes (ard-1, rpn-7, cpz-1, his-7, cdk-1, rnr-1, clsp-1, and spp-1), when knocked down by RNA interference, efficiently suppressed the plate-level multivulva phenotype of pry-1 mutants. In every case, other than clsp-1 and spp-1, the ectopic vulval precursor cell (VPC) induction was also inhibited. The suppressor genes are members of known gene families in eukaryotes and perform essential functions. Our genetic interaction experiments revealed that except for clsp-1, the genes participate in one or more pry-1-mediated biological events. While four of them (cpz-1, his-7, cdk-1, and rnr-1) function in VPC induction, stress response, and aging, the other three (spp-1, ard-1, and rpn-7) are specific to one or more of these processes. Further analysis of the genes involved in aging showed that his-7, cdk-1, and rnr-1 also interacted with daf-16/FOXO. The results of genetic epistasis experiments suggested that his-7 functions upstream of daf-16, whereas cdk-1and rnr-1 act downstream of the pry-1-daf-16 pathway. Altogether, these findings demonstrate the important role of pry-1 suppressors in C. elegans. Given that all of the genes described in this study are conserved, future investigations of their interactions with Axin and their functional specificity promises to uncover the genetic network of Axin under normal and disease states.

scholarly journals Genetic analysis of Caenorhabditis elegans pry-1/Axin suppressors identifies genes involved in reproductive structure development, stress responses, and aging

2021 ◽  
Author(s):  
Avijit Mallick ◽  
Nikita Jhaveri ◽  
Jihae Jeon ◽  
Yvonne Chang ◽  
Krupali Shah ◽  
...  
Keyword(s):  
Caenorhabditis Elegans ◽  
Stress Response ◽  
Stress Responses ◽  
Genetic Interaction ◽  
Gene Families ◽  
Genetic Network ◽  
Reproductive Structure ◽  
Structure Development ◽  
Developmental Processes ◽  
C Elegans

Abstract The Axin family of scaffolding proteins regulates a wide array of developmental and post-developmental processes in eukaryotes. Studies in the nematode Caenorhabditis elegans have shown that the Axin homolog PRY-1 plays essential roles in multiple tissues. To understand the genetic network of pry-1, we focused on a set of genes that are differentially expressed in the pry-1-mutant transcriptome and are linked to reproductive structure development. Knocking down eight of the genes (spp-1, clsp-1, ard-1, rpn-7, cpz-1, his-7, cdk-1, and rnr-1) via RNA interference efficiently suppressed the multivulva phenotype of pry-1 mutants. In all cases, the ectopic induction of P3.p vulval precursor cell was also inhibited. The suppressor genes are members of known gene families in eukaryotes and perform essential functions. Our genetic interaction experiments revealed that in addition to their role in vulval development, these genes participate in one or more pry-1-mediated biological events. Whereas four of them (cpz-1, his-7, cdk-1, and rnr-1) function in both stress response and aging, two (spp-1 and ard-1) are specific to stress response. Altogether, these findings demonstrate the important role of pry-1 suppressors in regulating developmental and post-developmental processes in C. elegans. Given that the genes described in this study are conserved, future investigations of their interactions with Axin and their functional specificity promises to uncover the genetic network of Axin in metazoans.

scholarly journals Enhancers of glp-1, a gene required for cell-signaling in Caenorhabditis elegans, define a set of genes required for germline development.

Genetics ◽  
1995 ◽  
Vol 141 (2) ◽  
pp. 551-569 ◽  
Author(s):  
L Qiao ◽  
J L Lissemore ◽  
P Shu ◽  
A Smardon ◽  
M B Gelber ◽  
...  
Keyword(s):  
Caenorhabditis Elegans ◽  
Cell Signaling ◽  
Cell Fate ◽  
Gene Families ◽  
Loss Of Function ◽  
Germline Development ◽  
Somatic Development ◽  
C Elegans ◽  
Functional Relationships ◽  
New Genes

Abstract The distal tip cell (DTC) regulates the proliferation or differentiation choice in the Caenorhabditis elegans germline by an inductive mechanism. Cell signaling requires a putative receptor in the germline, encoded b y the glp-1 gene, and a putative signal from the DTC, encoded by the lag-2 gene. Both glp-1 and lag-2 belong to multigene gene families whose members are essential for cell signaling during development of various tissues in insects and vertebrates as well as C. elegans. Relatively little is known about how these pathways regulate cell fate choice. To identify additional genes involved in the glp-1 signaling pathway, we carried out screens for genetic enhancers of glp-1. We recovered mutations in five new genes, named ego (enhancer of glp-1), and two previously identified genes, lag-1 and glp-4, that strongly enhance a weak glp-1 loss-of-function phenotype in the germline. Ego mutations cause multiple phenotypes consistent with the idea that gene activity is required for more than one aspect of germline and, in some cases, somatic development. Based on genetic experiments, glp-1 appears to act upstream of ego-1 and ego-3. We discuss the possible functional relationships among these genes in light of their phenotypes and interactions with glp-1.

scholarly journals FUSTr: a tool to find gene families under selection in transcriptomes

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e4234 ◽  
Author(s):  
T. Jeffrey Cole ◽  
Michael S. Brewer
Keyword(s):  
Molecular Evolution ◽  
Positive Selection ◽  
High Performance ◽  
Large Scale ◽  
Simulated Data ◽  
Gene Families ◽  
Strong Positive Selection ◽  
Transcriptomic Data ◽  
Downstream Analysis ◽  
User Friendly

Background The recent proliferation of large amounts of biodiversity transcriptomic data has resulted in an ever-expanding need for scalable and user-friendly tools capable of answering large scale molecular evolution questions. FUSTr identifies gene families involved in the process of adaptation. This is a tool that finds genes in transcriptomic datasets under strong positive selection that automatically detects isoform designation patterns in transcriptome assemblies to maximize phylogenetic independence in downstream analysis. Results When applied to previously studied spider transcriptomic data as well as simulated data, FUSTr successfully grouped coding sequences into proper gene families as well as correctly identified those under strong positive selection in relatively little time. Conclusions FUSTr provides a useful tool for novice bioinformaticians to characterize the molecular evolution of organisms throughout the tree of life using large transcriptomic biodiversity datasets and can utilize multi-processor high-performance computational facilities.

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