scholarly journals Integrating phylogenetic and network approaches to study gene family evolution: the case of the AGAMOUS family of floral genes

2017 ◽  
Author(s):  
Daniel S. Carvalho ◽  
James C. Schnable ◽  
Ana Maria R. Almeida

AbstractThe study of gene family evolution has benefited from the use of phylogenetic tools, which can greatly inform studies of both relationships within gene families and functional divergence. Here, we propose the use of a network-based approach that in combination with phylogenetic methods can provide additional support for models of gene family evolution. We dissect the contributions of each method to the improved understanding of relationships and functions within the well-characterized family of AGAMOUS floral development genes. The results obtained with the two methods largely agreed with one another. In particular, we show how network approaches can provide improved interpretations of branches with low support in a conventional gene tree. The network approach used here may also better reflect known and suspected patterns of functional divergence relative to phylogenetic methods. Overall, we believe that the combined use of phylogenetic and network tools provide more robust assessments of gene family evolution.

2020 ◽  
Author(s):  
Jennifer A. Noble ◽  
Ming-Che James Liu ◽  
Thomas A. DeFalco ◽  
Martin Stegmann ◽  
Kara McNamara ◽  
...  

AbstractA signaling complex comprising members of the LORELEI (LRE)-LIKE GPI-anchored protein (LLG) and Catharanthus roseus RECEPTOR-LIKE KINASE 1-LIKE (CrRLK1L) families perceive RAPID ALKALINIZATION FACTOR (RALF) peptides and regulate growth, development, reproduction, and immunity in Arabidopsis thaliana. Duplications in each component, which potentially could generate thousands of combinations of this signaling complex, are also evident in other angiosperms. Widespread duplication in angiosperms raises the question what evolutionary mechanisms underlie the expansion and retention of these gene families, as duplicated genes are typically rendered non-functional. As genetic and genomic resources make it a tractable model system, here we investigated this question using LLG gene family evolution and function in Brassicaceae. We first established that the LLG homologs in the Brassicaceae resulted from duplication events that pre-date the divergence of species in this family. Complementation of vegetative phenotypes in llg1 by LRE, LLG2, and LLG3 showed that the molecular functions of LLG homologs in A. thaliana are conserved. We next tested the possibility that differences in gene expression (regulatory subfunctionalization), rather than functional divergence, played a role in retention of these duplicated genes. For this, we examined the function and expression of LRE and LLG1 in A. thaliana and their single copy ortholog in Cleome violacea (Clevi LRE/LLG1), a representative species outside the Brassicaceae, but from the same order (Brassicales). We showed that expression of LLG1 and LRE did not overlap in A. thaliana and that Clevi-LRE/LLG1 expression in C. violacea encompassed all the expression domains of A. thaliana LRE + LLG1. Still, complementation experiments showed that LLG1 rescued reproductive phenotypes in lre and that Clevi LRE/LLG1 rescued both vegetative and reproductive phenotypes in llg1 and lre. Additionally, we found that expression of LLG2 and LLG3 in A. thaliana have also diverged from the expression of their corresponding single copy ortholog (Clevi LLG2/LLG3) in C. violacea. Our findings demonstrated how regulatory subfunctionalization, rather than functional divergence, underlies the retention of the LLG gene family in Brassicaceae. Our findings on the regulatory divergence and functional conservation provide an experimental framework to characterize the combinatorial assembly and function of this critical plant cell signaling complex.


Author(s):  
Andrew W Legan ◽  
Christopher M Jernigan ◽  
Sara E Miller ◽  
Matthieu F Fuchs ◽  
Michael J Sheehan

Abstract Independent origins of sociality in bees and ants are associated with independent expansions of particular odorant receptor (OR) gene subfamilies. In ants, one clade within the OR gene family, the 9-exon subfamily, has dramatically expanded. These receptors detect cuticular hydrocarbons (CHCs), key social signaling molecules in insects. It is unclear to what extent 9-exon OR subfamily expansion is associated with the independent evolution of sociality across Hymenoptera, warranting studies of taxa with independently derived social behavior. Here we describe odorant receptor gene family evolution in the northern paper wasp, Polistes fuscatus, and compare it to four additional paper wasp species spanning ∼40 million years of evolutionary divergence. We find 200 putatively functional OR genes in P. fuscatus, matching predictions from neuroanatomy, and more than half of these are in the 9-exon subfamily. Most OR gene expansions are tandemly arrayed at orthologous loci in Polistes genomes, and microsynteny analysis shows species-specific gain and loss of 9-exon ORs within tandem arrays. There is evidence of episodic positive diversifying selection shaping ORs in expanded subfamilies. Values of omega (d  N/dS) are higher among 9-exon ORs compared to other OR subfamilies. Within the Polistes OR gene tree, branches in the 9-exon OR clade experience relaxed negative (purifying) selection relative to other branches in the tree. Patterns of OR evolution within Polistes are consistent with 9-exon OR function in CHC perception by combinatorial coding, with both natural selection and neutral drift contributing to interspecies differences in gene copy number and sequence.


2021 ◽  
Author(s):  
Kim Vertacnik ◽  
Danielle Herrig ◽  
R Keating Godfrey ◽  
Tom Hill ◽  
Scott Geib ◽  
...  

A central goal in evolutionary biology is to determine the predictability of adaptive genetic changes. Despite many documented cases of convergent evolution at individual loci, little is known about the repeatability of gene family expansions and contractions. To address this void, we examined gene family evolution in the redheaded pine sawfly Neodiprion lecontei, a non-eusocial hymenopteran and exemplar of a pine-specialized lineage evolved from angiosperm-feeding ancestors. After assembling and annotating a draft genome, we manually annotated multiple gene families with chemosensory, detoxification, or immunity functions and characterized their genomic distributions and evolutionary history. Our results suggest that expansions of bitter gustatory receptor (GR), clan 3 cytochrome P450 (CYP3), and antimicrobial peptide (AMP) subfamilies may have contributed to pine adaptation. By contrast, there was no evidence of recent gene family contraction via pseudogenization. Next, we compared the number of genes in these same families across insect taxa that vary in diet, dietary specialization, and social behavior. In Hymenoptera, herbivory was associated with large GR and small olfactory receptor (OR) families, eusociality was associated with large OR and small AMP families, and--unlike investigations among more closely related taxa--ecological specialization was not related to gene family size. Overall, our results suggest that gene families that mediate ecological interactions may expand and contract predictably in response to particular selection pressures, however, the ecological drivers and temporal pace of gene gain and loss likely varies considerably across gene families.


2019 ◽  
Author(s):  
Laura Hernández ◽  
Alberto Vicens ◽  
Luis Enrique Eguiarte ◽  
Valeria Souza ◽  
Valerie De Anda ◽  
...  

ABSTRACTDimethylsulfoniopropionate (DMSP), an osmolyte produced by oceanic phytoplankton, is predominantly degraded by bacteria belonging to the Roseobacter lineage and other marine Alphaproteobacteria via DMSP-dependent demethylase A protein (DmdA). To date, the evolutionary history of DmdA gene family is unclear. Some studies indicate a common ancestry between DmdA and GcvT gene families and a co-evolution between Roseobacter and the DMSP-producing-phytoplankton around 250 million years ago (Mya). In this work, we analyzed the evolution of DmdA under three possible evolutionary scenarios: 1) a recent common ancestor of DmdA and GcvT, 2) a coevolution between Roseobacter and the DMSP-producing-phytoplankton, and 3) pre-adapted enzymes to DMSP prior to Roseobacter origin. Our analyses indicate that DmdA is a new gene family originated from GcvT genes by duplication and functional divergence driven by positive selection before a coevolution between Roseobacter and phytoplankton. Our data suggest that Roseobacter acquired dmdA by horizontal gene transfer prior to exposition to an environment with higher DMSP. Here, we propose that the ancestor that carried the DMSP demethylation pathway genes evolved in the Archean, and was exposed to a higher concentration of DMSP in a sulfur rich atmosphere and anoxic ocean, compared to recent Roseobacter ecoparalogs (copies performing the same function under different conditions), which should be adapted to lower concentrations of DMSP.


eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Milton Tan ◽  
Anthony K Redmond ◽  
Helen Dooley ◽  
Ryo Nozu ◽  
Keiichi Sato ◽  
...  

Chondrichthyes (cartilaginous fishes) are fundamental for understanding vertebrate evolution, yet their genomes are understudied. We report long-read sequencing of the whale shark genome to generate the best gapless chondrichthyan genome assembly yet with higher contig contiguity than all other cartilaginous fish genomes, and studied vertebrate genomic evolution of ancestral gene families, immunity, and gigantism. We found a major increase in gene families at the origin of gnathostomes (jawed vertebrates) independent of their genome duplication. We studied vertebrate pathogen recognition receptors (PRRs), which are key in initiating innate immune defense, and found diverse patterns of gene family evolution, demonstrating that adaptive immunity in gnathostomes did not fully displace germline-encoded PRR innovation. We also discovered a new Toll-like receptor (TLR29) and three NOD1 copies in the whale shark. We found chondrichthyan and giant vertebrate genomes had decreased substitution rates compared to other vertebrates, but gene family expansion rates varied among vertebrate giants, suggesting substitution and expansion rates of gene families are decoupled in vertebrate genomes. Finally, we found gene families that shifted in expansion rate in vertebrate giants were enriched for human cancer-related genes, consistent with gigantism requiring adaptations to suppress cancer.


PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e9861
Author(s):  
Laura Hernández ◽  
Alberto Vicens ◽  
Luis E. Eguiarte ◽  
Valeria Souza ◽  
Valerie De Anda ◽  
...  

Dimethylsulfoniopropionate (DMSP), an osmolyte produced by oceanic phytoplankton and bacteria, is primarily degraded by bacteria belonging to the Roseobacter lineage and other marine Alphaproteobacteria via DMSP-dependent demethylase A protein (DmdA). To date, the evolutionary history of DmdA gene family is unclear. Some studies indicate a common ancestry between DmdA and GcvT gene families and a co-evolution between Roseobacter and the DMSP-producing-phytoplankton around 250 million years ago (Mya). In this work, we analyzed the evolution of DmdA under three possible evolutionary scenarios: (1) a recent common ancestor of DmdA and GcvT, (2) a coevolution between Roseobacter and the DMSP-producing-phytoplankton, and (3) an enzymatic adaptation for utilizing DMSP in marine bacteria prior to Roseobacter origin. Our analyses indicate that DmdA is a new gene family originated from GcvT genes by duplication and functional divergence driven by positive selection before a coevolution between Roseobacter and phytoplankton. Our data suggest that Roseobacter acquired dmdA by horizontal gene transfer prior to an environment with higher DMSP. Here, we propose that the ancestor that carried the DMSP demethylation pathway genes evolved in the Archean, and was exposed to a higher concentration of DMSP in a sulfur-rich atmosphere and anoxic ocean, compared to recent Roseobacter eco-orthologs (orthologs performing the same function under different conditions), which should be adapted to lower concentrations of DMSP.


2020 ◽  
Vol 12 (3) ◽  
pp. 185-202
Author(s):  
Xia Han ◽  
Jindan Guo ◽  
Erli Pang ◽  
Hongtao Song ◽  
Kui Lin

Abstract How have genes evolved within a well-known genome phylogeny? Many protein-coding genes should have evolved as a whole at the gene level, and some should have evolved partly through fragments at the subgene level. To comprehensively explore such complex homologous relationships and better understand gene family evolution, here, with de novo-identified modules, the subgene units which could consecutively cover proteins within a set of closely related species, we applied a new phylogeny-based approach that considers evolutionary models with partial homology to classify all protein-coding genes in nine Drosophila genomes. Compared with two other popular methods for gene family construction, our approach improved practical gene family classifications with a more reasonable view of homology and provided a much more complete landscape of gene family evolution at the gene and subgene levels. In the case study, we found that most expanded gene families might have evolved mainly through module rearrangements rather than gene duplications and mainly generated single-module genes through partial gene duplication, suggesting that there might be pervasive subgene rearrangement in the evolution of protein-coding gene families. The use of a phylogeny-based approach with partial homology to classify and analyze protein-coding gene families may provide us with a more comprehensive landscape depicting how genes evolve within a well-known genome phylogeny.


2019 ◽  
Vol 20 (7) ◽  
pp. 1750 ◽  
Author(s):  
Ghulam Qanmber ◽  
Ji Liu ◽  
Daoqian Yu ◽  
Zhao Liu ◽  
Lili Lu ◽  
...  

Proline-rich extensin-like receptor kinases (PERKs) are an important class of receptor kinases in plants. Receptor kinases comprise large gene families in many plant species, including the 15 PERK genes in Arabidopsis. At present, there is no comprehensive published study of PERK genes in G. hirsutum. Our study identified 33 PERK genes in G. hirsutum. Phylogenetic analysis of conserved PERK protein sequences from 15 plant species grouped them into four well defined clades. The GhPERK gene family is an evolutionarily advanced gene family that lost its introns over time. Several cis-elements were identified in the promoter regions of the GhPERK genes that are important in regulating growth, development, light responses and the response to several stresses. In addition, we found evidence for gene loss or addition through segmental or whole genome duplication in cotton. Gene duplication and synteny analysis identified 149 orthologous/paralogous gene pairs. Ka/Ks values show that most GhPERK genes experienced strong purifying selection during the rapid evolution of the gene family. GhPERK genes showed high expression levels in leaves and during ovule development. Furthermore, the expression of GhPERK genes can be regulated by abiotic stresses and phytohormone treatments. Additionally, PERK genes could be involved in several molecular, biological and physiological processes that might be the result of functional divergence.


Genetics ◽  
1997 ◽  
Vol 147 (3) ◽  
pp. 1259-1266 ◽  
Author(s):  
Joseph H Nadeau ◽  
David Sankoff

Duplicated genes are an important source of new protein functions and novel developmental and physiological pathways. Whereas most models for fate of duplicated genes show that they tend to be rapidly lost, models for pathway evolution suggest that many duplicated genes rapidly acquire novel functions. Little empirical evidence is available, however, for the relative rates of gene loss vs. divergence to help resolve these contradictory expectations. Gene families resulting from genome duplications provide an opportunity to address this apparent contradiction. With genome duplication, the number of duplicated genes in a gene family is at most 2n, where n is the number of duplications. The size of each gene family, e.g., 1, 2, 3,..., 2n, reflects the patterns of gene loss vs. functional divergence after duplication. We focused on gene families in humans and mice that arose from genome duplications in early vertebrate evolution and we analyzed the frequency distribution of gene family size, i.e., the number of families with two, three or four members. All the models that we evaluated showed that duplicated genes are almost as likely to acquire a new and essential function as to be lost through acquisition of mutations that compromise protein function. An explanation for the unexpectedly high rate of functional divergence is that duplication allows genes to accumulate more neutral than disadvantageous mutations, thereby providing more opportunities to acquire diversified functions and pathways.


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