scholarly journals Understanding the adaptive evolution of mitochondrial genomes in intertidal chitons

2020 ◽  
Author(s):  
Dipanjana Dhar ◽  
Debayan Dey ◽  
Soumalee Basu ◽  
Helena Fortunato
Keyword(s):  
Adaptive Evolution ◽  
Intertidal Zone ◽  
Molecular Mechanisms ◽  
Proton Translocation ◽  
Protein Structures ◽  
Dynamic Environment ◽  
Extreme Environment ◽  
Protein Coding ◽  
Protein Coding Genes ◽  
Genetic Components

AbstractMitochondria are the centre of energy metabolism in eukaryotic cells and its genes are thus key to the evolution of molecular mechanisms that metabolize cellular energy. Intertidal zone is one of the most stressful environments with extreme shifts in temperature, salinity, pH and oxygen concentrations. Marine molluscs, particularly chitons belong to the ecologically dominant organisms in this extreme environment, symbolizing an ideal model to understand mitochondrial stress adaptation. Here, we used concatenated mitochondrial genetic components separately from seven chitons of the intertidal zone to reconstruct phylogenetic relationships among these species. We performed selection analyses considering sites and branches of individual protein-coding genes to identify potentially adaptive residues and localize them in the protein structures of mt subunits. Our results exhibited significant amino acid changes in sites under diversifying selection of all the protein-coding genes, indicative of the adaptive evolution of mitochondrial genome in chitons. Furthermore, we obtained sites in the transmembrane helices lining the proton translocation channel as well as in surrounding loop regions, providing implication towards functional modification of the OXPHOS proteins essential for survival in dynamic environment of the intertidal zone.

scholarly journals Comparative analysis of chloroplast genomes for five Dicliptera species (Acanthaceae): molecular structure, phylogenetic relationships, and adaptive evolution

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e8450 ◽  
Author(s):  
Sunan Huang ◽  
Xuejun Ge ◽  
Asunción Cano ◽  
Betty Gaby Millán Salazar ◽  
Yunfei Deng
Keyword(s):  
Adaptive Evolution ◽  
Phylogenetic Relationships ◽  
Single Copy ◽  
Rrna Genes ◽  
Trna Genes ◽  
Evolutionary Analysis ◽  
Protein Coding ◽  
Variable Regions ◽  
Protein Coding Genes ◽  
Chloroplast Genomes

The genus Dicliptera (Justicieae, Acanthaceae) consists of approximately 150 species distributed throughout the tropical and subtropical regions of the world. Newly obtained chloroplast genomes (cp genomes) are reported for five species of Dilciptera (D. acuminata, D. peruviana, D. montana, D. ruiziana and D. mucronata) in this study. These cp genomes have circular structures of 150,689–150,811 bp and exhibit quadripartite organizations made up of a large single copy region (LSC, 82,796–82,919 bp), a small single copy region (SSC, 17,084–17,092 bp), and a pair of inverted repeat regions (IRs, 25,401–25,408 bp). Guanine-Cytosine (GC) content makes up 37.9%–38.0% of the total content. The complete cp genomes contain 114 unique genes, including 80 protein-coding genes, 30 transfer RNA (tRNA) genes, and four ribosomal RNA (rRNA) genes. Comparative analyses of nucleotide variability (Pi) reveal the five most variable regions (trnY-GUA-trnE-UUC, trnG-GCC, psbZ-trnG-GCC, petN-psbM, and rps4-trnL-UUA), which may be used as molecular markers in future taxonomic identification and phylogenetic analyses of Dicliptera. A total of 55-58 simple sequence repeats (SSRs) and 229 long repeats were identified in the cp genomes of the five Dicliptera species. Phylogenetic analysis identified a close relationship between D. ruiziana and D. montana, followed by D. acuminata, D. peruviana, and D. mucronata. Evolutionary analysis of orthologous protein-coding genes within the family Acanthaceae revealed only one gene, ycf15, to be under positive selection, which may contribute to future studies of its adaptive evolution. The completed genomes are useful for future research on species identification, phylogenetic relationships, and the adaptive evolution of the Dicliptera species.

scholarly journals A Bayesian Mutation–Selection Framework for Detecting Site-Specific Adaptive Evolution in Protein-Coding Genes

2020 ◽  
Author(s):  
Nicolas Rodrigue ◽  
Thibault Latrille ◽  
Nicolas Lartillot
Keyword(s):  
Adaptive Evolution ◽  
Real Data ◽  
Data Sets ◽  
Protein Coding ◽  
Site Specific ◽  
Protein Coding Genes ◽  
Codon Substitution ◽  
Selection Framework ◽  
Dna Alignment ◽  
The Impact

Abstract In recent years, codon substitution models based on the mutation–selection principle have been extended for the purpose of detecting signatures of adaptive evolution in protein-coding genes. However, the approaches used to date have either focused on detecting global signals of adaptive regimes—across the entire gene—or on contexts where experimentally derived, site-specific amino acid fitness profiles are available. Here, we present a Bayesian site-heterogeneous mutation–selection framework for site-specific detection of adaptive substitution regimes given a protein-coding DNA alignment. We offer implementations, briefly present simulation results, and apply the approach on a few real data sets. Our analyses suggest that the new approach shows greater sensitivity than traditional methods. However, more study is required to assess the impact of potential model violations on the method, and gain a greater empirical sense its behavior on a broader range of real data sets. We propose an outline of such a research program.

scholarly journals Integrated structural and evolutionary analysis reveals common mechanisms underlying adaptive evolution in mammals

2020 ◽  
Vol 117 (11) ◽  
pp. 5977-5986 ◽  
Author(s):  
Greg Slodkowicz ◽  
Nick Goldman
Keyword(s):  
Positive Selection ◽  
Adaptive Evolution ◽  
Evolutionary Biology ◽  
Molecular Mechanisms ◽  
Structural Information ◽  
Protein Structures ◽  
Unexpected Finding ◽  
Evolutionary Analysis ◽  
Genomic Scale ◽  
Evolution Of Mammals

Understanding the molecular basis of adaptation to the environment is a central question in evolutionary biology, yet linking detected signatures of positive selection to molecular mechanisms remains challenging. Here we demonstrate that combining sequence-based phylogenetic methods with structural information assists in making such mechanistic interpretations on a genomic scale. Our integrative analysis shows that positively selected sites tend to colocalize on protein structures and that positively selected clusters are found in functionally important regions of proteins, indicating that positive selection can contravene the well-known principle of evolutionary conservation of functionally important regions. This unexpected finding, along with our discovery that positive selection acts on structural clusters, opens previously unexplored strategies for the development of better models of protein evolution. Remarkably, proteins where we detect the strongest evidence of clustering belong to just two functional groups: Components of immune response and metabolic enzymes. This gives a coherent picture of pathogens and xenobiotics as important drivers of adaptive evolution of mammals.

A novel rearrangement in the mitochondrial genome of tongue sole, Cynoglossus semilaevis: control region translocation and a tRNA gene inversion

Genome ◽  
2009 ◽  
Vol 52 (12) ◽  
pp. 975-984 ◽  
Author(s):  
Xiaoyu Kong ◽  
Xiaoli Dong ◽  
Yanchun Zhang ◽  
Wei Shi ◽  
Zhongming Wang ◽  
...  
Keyword(s):  
Control Region ◽  
Molecular Mechanisms ◽  
Cynoglossus Semilaevis ◽  
Rrna Genes ◽  
Trna Genes ◽  
Protein Coding ◽  
Protein Coding Genes ◽  
Heavy Strand ◽  
Light Strand ◽  
Putative Control Region

The organization of fish mitochondrial genomes (mitogenomes) is quite conserved, usually with the heavy strand encoding 12 of 13 protein-coding genes and 14 of 22 tRNA genes, and the light strand encoding ND6 and the remaining 8 tRNA genes. Currently, there are only a few reports on gene reorganization of fish mitogenomes, with only two types of rearrangements (shuffling and translocation) observed. No gene inversion has been detected in approximately 420 complete fish mitogenomes available so far. Here we report a novel rearrangement in the mitogenome of Cynoglossus semilaevis (Cynoglossinae, Cynoglossidae, Pleuronectiformes). The genome is 16 371 bp in length and contains 13 protein-coding genes, 2 rRNA genes, 22 tRNA genes, and 2 main noncoding regions, the putative control region and the light-strand replication origin. A striking finding of this study is that the tRNAGln gene is translocated from the light to the heavy strand (Q inversion). This is accompanied by shuffling of the tRNAIle gene and long-range translocation of the putative control region downstream to a site between ND1 and the tRNAGln gene. The remaining gene order is identical to that of typical fish mitogenomes. Additionally, unique characters of this mitogenome, including a high A+T content and length variations of 8 protein-coding genes, were found through comparison of the mitogenome sequence with those from other flatfishes. All the features detected and their relationships with the rearrangements, as well as a possible rearrangement pathway, are discussed. These data provide interesting information for better understanding the molecular mechanisms of gene reorganization in fish mitogenomes.

scholarly journals Preliminary assessment of adaptive evolution of mitochondrial protein coding genes in darters (Percidae: Etheostomatinae)

F1000Research ◽  
2019 ◽  
Vol 8 ◽  
pp. 464 ◽  
Author(s):  
Leos G. Kral ◽  
Sara Watson
Keyword(s):  
Positive Selection ◽  
Adaptive Evolution ◽  
Gene Evolution ◽  
Mitochondrial Gene ◽  
Mitochondrial Protein ◽  
Preliminary Assessment ◽  
Protein Coding ◽  
Protein Coding Genes ◽  
Show Evidence ◽  
Selection Of

Background: Mitochondrial DNA of vertebrates contains genes for 13 proteins involved in oxidative phosphorylation. Some of these genes have been shown to undergo adaptive evolution in a variety of species. This study examines all mitochondrial protein coding genes in 11 darter species to determine if any of these genes show evidence of positive selection. Methods: The mitogenome from four darter was sequenced and annotated. Mitogenome sequences for another seven species were obtained from GenBank. Alignments of each of the protein coding genes were subject to codon-based identification of positive selection by Selecton, MEME and FEL. Results: Evidence of positive selection was obtained for six of the genes by at least one of the methods. CYTB was identified as having evolved under positive selection by all three methods at the same codon location. Conclusions: Given the evidence for positive selection of mitochondrial protein coding genes in darters, a more extensive analysis of mitochondrial gene evolution in all the extant darter species is warranted.

scholarly journals Chromosome-level genome assembly of a butterflyfish, Chelmon rostratus

2019 ◽  
Author(s):  
Xiaoyun Huang ◽  
Yue Song ◽  
Suyu Zhang ◽  
A Yunga ◽  
Mengqi Zhang ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Repetitive Sequences ◽  
Ecological Environment ◽  
Protein Coding ◽  
Protein Coding Genes ◽  
A Genome ◽  
Genome Information ◽  
Adaptation Evolution ◽  
Core Genes ◽  
Chromosome Level

AbstractChelmon rostratus (Teleostei, Perciformes, Chaetodontidae) is a copperband butterflyfish. As an ornamental fish, the genome information for this species might help understanding the genome evolution of Chaetodontidae and adaptation/evolution of coral reef fish.In this study, using the stLFR co-Barcode reads data, we assembled a genome of 638.70 Mb in size with contig and scaffold N50 sizes of 294.41 kb and 2.61 Mb, respectively. 94.40% of scaffold sequences were assigned to 24 chromosomes using Hi-C data and BUSCO analysis showed that 97.3% (2,579) of core genes were found in our assembly. Up to 21.47 % of the genome was found to be repetitive sequences and 21,375 protein-coding genes were annotated. Among these annotated protein-coding genes, 20,163 (94.33%) proteins were assigned with possible functions.As the first genome for Chaetodontidae family, the information of these data helpfully to improve the essential to the further understanding and exploration of marine ecological environment symbiosis with coral and the genomic innovations and molecular mechanisms contributing to its unique morphology and physiological features.

scholarly journals Comparison of Evolutionary Selection Acting on the Mitochondrial Protein-Coding Genes Between Intertidal and Deep-Sea Gastropods

2021 ◽  
Vol 8 (5) ◽  
Author(s):  
Dipanjana Dhar ◽  
Debayan Dey
Keyword(s):  
Energy Metabolism ◽  
Deep Sea ◽  
Intertidal Zone ◽  
Mitochondrial Protein ◽  
Low Oxygen ◽  
Protein Coding ◽  
Marine Gastropods ◽  
Protein Coding Genes ◽  
Ideal System ◽  
And Shifts

Marine molluscs are ecologically and economically important group of organisms that survive in the challenging environments of different oceanic zones. Of all the classes of the phylum Mollusca, gastropods have radiated into marine, freshwater and terrestrial habitats, successfully adapting themselves to thrive in changing environmental conditions. Hence, marine gastropods can be considered as an ideal system to study stress adaptation. In order to withstand the constant fluctuations in temperature, salinity and shifts in oxygen concentration of the intertidal zone, the gastropods inhabiting here rely on a modified and adaptive energy metabolism. The same is applicable for gastropods living in the deep sea environment, which is characterized by high hydrostatic pressure, low oxygen concentrations and abundance of heavy metals. Therefore, survival of these organisms may be correlated to their adaptive mitochondrial genome which serves as the principal site for energy metabolism and production in the cell. Here, we estimated selection pressure acting on the mitochondrial protein-coding genes of 13 intertidal and 2 deep sea gastropods based on site and branch-site specific models. The results exhibited higher number of sites under diversifying selection for the mitochondrial protein-coding genes of intertidal gastropods compared to deep sea species. Overall, this study focusses on the adaptive mitogenome evolution of marine gastropods for survival in the dynamic environments of the intertidal zone as well as deep sea.

scholarly journals Fact or fiction: updates on how protein-coding genes might emerge de novo from previously non-coding DNA

F1000Research ◽  
2017 ◽  
Vol 6 ◽  
pp. 57 ◽  
Author(s):  
Jonathan F Schmitz ◽  
Erich Bornberg-Bauer
Keyword(s):  
De Novo ◽  
Protein Structures ◽  
Divergence Times ◽  
Protein Coding ◽  
Future Studies ◽  
Functional Studies ◽  
Protein Coding Genes ◽  
Open Questions ◽  
Bona Fide

Over the last few years, there has been an increasing amount of evidence for the de novo emergence of protein-coding genes, i.e. out of non-coding DNA. Here, we review the current literature and summarize the state of the field. We focus specifically on open questions and challenges in the study of de novo protein-coding genes such as the identification and verification of de novo-emerged genes. The greatest obstacle to date is the lack of high-quality genomic data with very short divergence times which could help precisely pin down the location of origin of a de novo gene. We conclude that, while there is plenty of evidence from a genetics perspective, there is a lack of functional studies of bona fide de novo genes and almost no knowledge about protein structures and how they come about during the emergence of de novo protein-coding genes. We suggest that future studies should concentrate on the functional and structural characterization of de novo protein-coding genes as well as the detailed study of the emergence of functional de novo protein-coding genes.

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