scholarly journals Not Frozen in the Ice: large and Dynamic Rearrangements in the Mitochondrial Genomes of the Antarctic Fish

2021 ◽  
Author(s):  
Chiara Papetti ◽  
Massimiliano Babbucci ◽  
Agnes Dettai ◽  
Andrea Basso ◽  
Magnus Lucassen ◽  
...  
Keyword(s):  
Gene Order ◽  
Hot Spot ◽  
Mitochondrial Gene ◽  
Antarctic Fish ◽  
Purifying Selection ◽  
Compositional Bias ◽  
Mitochondrial Genomes ◽  
Notothenioid Fish ◽  
Antarctic Notothenioids ◽  
The Antarctic

Abstract The vertebrate mitochondrial genomes generally present a typical gene order. Exceptions are uncommon and important to study the genetic mechanisms of gene order rearrangements and their consequences on phylogenetic output and mitochondrial function. Antarctic notothenioid fish carry some peculiar rearrangements of the mitochondrial gene order. In this first systematic study of 28 species, we analysed known and undescribed mitochondrial genome rearrangements for a total of eight different gene orders within the notothenioid fish. Our reconstructions suggest that transpositions, duplications and inversion of multiple genes are the most likely mechanisms of rearrangement in notothenioid mitochondrial genomes. In Trematominae, we documented an extremely rare inversion of a large genomic segment of 5300 bp that partially affected the gene compositional bias but not the phylogenetic output. The genomic region delimited by nad5 and trnF, close to the area of the Control Region, was identified as the hot spot of variation in Antarctic fish mitochondrial genomes. Analysing the sequence of several intergenic spacers and mapping the arrangements on a newly generated phylogeny showed that the entire history of the Antarctic notothenioids is characterized by multiple, relatively rapid, events of disruption of the gene order. We hypothesised that a pre-existing genomic flexibility of the ancestor of the Antarctic notothenioids may have generated a precondition for gene order rearrangement, and the pressure of purifying selection could have worked for a rapid restoration of the mitochondrial functionality and compactness after each event of rearrangement.

scholarly journals Mitochondrial Genomes from Two Specialized Subfamilies of Reduviidae (Insecta: Hemiptera) Reveal Novel Gene Rearrangements of True Bugs

Genes ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 1134
Author(s):  
Fei Ye ◽  
Hu Li ◽  
Qiang Xie
Keyword(s):  
Gene Rearrangement ◽  
Hot Spot ◽  
Phylogenetic Analyses ◽  
Mitochondrial Gene ◽  
Deep Understanding ◽  
Gene Arrangement ◽  
Mitochondrial Genomes ◽  
Current View ◽  
Novel Gene ◽  
Spot Group

Reduviidae, a hyper-diverse family, comprise 25 subfamilies with nearly 7000 species and include many natural enemies of crop pests and vectors of human disease. To date, 75 mitochondrial genomes (mitogenomes) of assassin bugs from only 11 subfamilies have been reported. The limited sampling of mitogenome at higher categories hinders a deep understanding of mitogenome evolution and reduviid phylogeny. In this study, the first mitogenomes of Holoptilinae (Ptilocnemus lemur) and Emesinae (Ischnobaenella hainana) were sequenced. Two novel gene orders were detected in the newly sequenced mitogenomes. Combined 421 heteropteran mitogenomes, we identified 21 different gene orders and six gene rearrangement units located in three gene blocks. Comparative analyses of the diversity of gene order for each unit reveal that the tRNA gene cluster trnI-trnQ-trnM is the hotspot of heteropteran gene rearrangement. Furthermore, combined analyses of the gene rearrangement richness of each unit and the whole mitogenome among heteropteran lineages confirm Reduviidae as a ‘hot-spot group’ of gene rearrangement in Heteroptera. The phylogenetic analyses corroborate the current view of phylogenetic relationships between basal groups of Reduviidae with high support values. Our study provides deeper insights into the evolution of mitochondrial gene arrangement in Heteroptera and the early divergence of reduviids.

scholarly journals Linear Mitochondrial genome in Anthozoa (Cnidaria): A case study in Ceriantharia

2018 ◽  
Author(s):  
Sergio N Stampar ◽  
Michael B Broe ◽  
Jason Macrander ◽  
Adam M Reitzel ◽  
Marymegan Daly
Keyword(s):  
Mitochondrial Genome ◽  
Gene Order ◽  
Mitochondrial Gene ◽  
Phylogenetic Position ◽  
Mitochondrial Genomes ◽  
Gene Sequences ◽  
Phylogenetic Placement ◽  
Organellar Genome ◽  
Linear Mitochondrial Genome

Sequences and structural attributes of mitochondrial genomes have played a key role in the clarification of relationships among Cnidaria, a key phylum of early-diverging animals. Among the major lineages of Cnidaria, Ceriantharia ("tube anemones") remains one of the most enigmatic groups in terms of its phylogenetic position. We sequenced the mitochondrial genomes of two ceriantharians to see whether the complete organellar genome would provide more support for the phylogenetic placement of Ceriantharia. For both ceriantharian species studied, the mitochondrial gene sequences could not be assembled into a circular genome. Instead, our analyses suggest both species have fragmented mitochondrial genomes consisting of multiple linear fragments. Linear mitogenomes are characteristic of members of Medusozoa, one of the major lineages of Cnidaria, but are unreported for Anthozoa, which includes the Ceriantharia. The number of fragments and the variation in gene order between species is much greater in Ceriantharia than among Medusozoa. The novelty of the mitogenomic structure in Ceriantharia highlights the distinctiveness of this lineage but, because it appears to be both unique to and diverse within Ceriantharia, it is uninformative about the phylogenetic position of Ceriantharia relative to other anthozoan groups.

Mitochondrial gene rearrangements as phylogenetic characters in the invertebrates: the examination of genome 'morphology'

2002 ◽  
Vol 16 (3) ◽  
pp. 345 ◽  
Author(s):  
M. Dowton ◽  
L. R. Castro ◽  
A. D. Austin
Keyword(s):  
Mitochondrial Genome ◽  
Gene Order ◽  
Gene Rearrangement ◽  
Mitochondrial Gene ◽  
Molecular Data ◽  
Mitochondrial Genomes ◽  
Gene Rearrangements ◽  
Genome Organisation ◽  
Rearrangement Mechanism ◽  
Molecular Characters

Mitochondrial gene rearrangements are the latest tool in the arsenal of phylogeneticists for investigating historical relationships. They are complex molecular characters that may provide more reliable evidence of ancestry than comparative molecular data. Here we review the phylogenetic utility of mitochondrial gene rearrangements, and find that despite isolated incidences of convergence, derived gene order appears highly congruent with phylogenies produced from other sources of data. We calculate that the chance of two mitochondrial genomes sharing the same derived genome organisation is only 1/2664, but caution that this ignores the possibility that the (as yet uncharacterised) gene rearrangement mechanism may greatly increase the chance of convergence. Broader taxonomic surveys of mitochondrial genome organisation will lead to a more realistic indication of the historical incidence of convergence in genome organisation.

scholarly journals Comprehensive Analyses of the Complete Mitochondrial Genome of Figulus binodulus (Coleoptera: Lucanidae)

2020 ◽  
Vol 20 (5) ◽  
Author(s):  
Jungmo Lee ◽  
Jonghyun Park ◽  
Hong Xi ◽  
Jongsun Park
Keyword(s):  
Mitochondrial Genome ◽  
Gene Order ◽  
Complete Mitochondrial Genome ◽  
Mitochondrial Gene ◽  
Mitochondrial Genomes ◽  
Protein Coding ◽  
Transfer Rnas ◽  
Mitochondrial Gene Order ◽  
Rna Genes ◽  
Simple Sequence

Abstract Figulus binodulus Waterhouse is a small stag beetle distributed in East Asia. We determined the first mitochondrial genome of F. binodulus of which is 16,261-bp long including 13 protein-coding genes, two ribosomal RNA genes, 22 transfer RNAs, and a single large noncoding region of 1,717 bp. Gene order of F. binodulus is identical to the ancestral insect mitochondrial gene order as in most other stag beetle species. All of 22 tRNAs could be shaped into typical clover-leaf structure except trnSer1. Comparative analyses of 21 Lucanidae mitochondrial genomes was conducted in aspect of their length and AT-GC ratio. Nucleotide diversities analyses provide that cox1 and cox2 in Lucanidae are less diverse than those of Scarabaeoidea. Fifty simple sequence repeats (SSRs) were identified on F. binodulus mitochondrial genome. Comparative analysis of SSRs among five mitochondrial genomes displayed similar trend along with SSR types. Figulus binodulus was sister to all other available family Lucanidae species in the phylogenetic tree.

scholarly journals Initial Phylotranscriptomic Confirmation of Homoplastic Evolution of the Conspicuous Coloration and Bufoniform Morphology of Pumpkin-Toadlets in the Genus Brachycephalus

Toxins ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 816
Author(s):  
Mariana L. Lyra ◽  
Juliane P. C. Monteiro ◽  
Loïs Rancilhac ◽  
Iker Irisarri ◽  
Sven Künzel ◽  
...  
Keyword(s):  
Gene Order ◽  
Convergent Evolution ◽  
Ecological Study ◽  
Mitochondrial Gene ◽  
Mitochondrial Genomes ◽  
Data Sets ◽  
Protein Coding ◽  
Protein Coding Genes ◽  
Mitochondrial Gene Order ◽  
Rnaseq Data

The genus Brachycephalus is a fascinating group of miniaturized anurans from the Brazilian Atlantic Forest, comprising the conspicuous, brightly colored pumpkin-toadlets and the cryptic flea-toads. Pumpkin-toadlets are known to contain tetrodotoxins and therefore, their bright colors may perform an aposematic function. Previous studies based on a limited number of mitochondrial and nuclear-encoded markers supported the existence of two clades containing species of pumpkin-toadlet phenotype, but deep nodes remained largely unresolved or conflicting between data sets. We use new RNAseq data of 17 individuals from nine Brachycephalus species to infer their evolutionary relationships from a phylogenomic perspective. Analyses of almost 5300 nuclear-encoded ortholog protein-coding genes and full mitochondrial genomes confirmed the existence of two separate pumpkin-toadlet clades, suggesting the convergent evolution (or multiple reversals) of the bufoniform morphology, conspicuous coloration, and probably toxicity. In addition, the study of the mitochondrial gene order revealed that three species (B. hermogenesi, B. pitanga, and B. rotenbergae) display translocations of different tRNAs (NCY and CYA) from the WANCY tRNA cluster to a position between the genes ATP6 and COIII, showing a new mitochondrial gene order arrangement for vertebrates. The newly clarified phylogeny suggests that Brachycephalus has the potential to become a promising model taxon to understand the evolution of coloration, body plan and toxicity. Given that toxicity information is available for only few species of Brachycephalus, without data for any flea-toad species, we also emphasize the need for a wider screening of toxicity across species, together with more in-depth functional and ecological study of their phenotypes.

scholarly journals Different gene rearrangements of the genus Dardanus (Anomura: Diogenidae) and insights into the phylogeny of Paguroidea

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ying Zhang ◽  
Lei Meng ◽  
Liming Wei ◽  
Xinting Lu ◽  
Bingjian Liu ◽  
...  
Keyword(s):  
Gene Order ◽  
Gene Rearrangement ◽  
Sequence Data ◽  
Sequence Similarity ◽  
Phylogenetic Analyses ◽  
Mitochondrial Gene ◽  
Purifying Selection ◽  
Sister Group ◽  
Genetic Distances ◽  
Hermit Crabs

AbstractComplete mitochondrial genomes (mitogenomes) can provide useful information for phylogenetic relationships, gene rearrangement, and molecular evolution. In this study, the complete mitogenomes of two hermit crabs, Dardanus arrosor and Dardanus aspersus, were sequenced for the first time and compared with other published mitogenomes of Paguroidea. Each of the two mitogenomes contains an entire set of 37 genes and a putative control region, but they display different gene arrangements. The different arrangements of the two mitogenomes might be the result of transposition, reversal, and tandem duplication/random loss events from the ancestral pancrustacean pattern. Genome sequence similarity analysis reveals the gene rearrangement in 15 Paguroidea mitogenomes. After synteny analysis between the 15 Paguroidea mitogenomes, an obvious rearranged region is found in D. aspersus mitogenome. Across the 13 protein-coding genes (PCGs) tested, COI has the least and ND6 has the largest genetic distances among the 15 hermit crabs, indicating varied evolution rates of PCGs. In addition, the dN/dS ratio analysis shows that all PCGs are evolving under purifying selection. The phylogenetic analyses based on both gene order and sequence data present the monophyly of three families (Paguridae, Coenobitidae, and Pylochelidae) and the paraphyly of the family Diogenidae. Meanwhile, the phylogenetic tree based on the nucleotide sequences of 13 PCGs shows that two Dardanus species formed a sister group with five Coenobitidae species. These findings help to better understand the gene rearrangement and phylogeny of Paguroidea, as well as provide new insights into the usefulness of mitochondrial gene order as a phylogenetic marker.

scholarly journals Phylogenetic Relationships and Adaptation in Deep-Sea Mussels: Insights from Mitochondrial Genomes

2021 ◽  
Vol 22 (4) ◽  
pp. 1900
Author(s):  
Kai Zhang ◽  
Jin Sun ◽  
Ting Xu ◽  
Jian-Wen Qiu ◽  
Pei-Yuan Qian
Keyword(s):  
Shallow Water ◽  
Deep Sea ◽  
Phylogenetic Relationships ◽  
Marine Invertebrates ◽  
Mitochondrial Gene ◽  
Purifying Selection ◽  
Mitochondrial Genomes ◽  
Excellent Source ◽  
Source Of Information ◽  
Tandem Duplications

Mitochondrial genomes (mitogenomes) are an excellent source of information for phylogenetic and evolutionary studies, but their application in marine invertebrates is limited. In the present study, we utilized mitogenomes to elucidate the phylogeny and environmental adaptation in deep-sea mussels (Mytilidae: Bathymodiolinae). We sequenced and assembled seven bathymodioline mitogenomes. A phylogenetic analysis integrating the seven newly assembled and six previously reported bathymodioline mitogenomes revealed that these bathymodiolines are divided into three well-supported clades represented by five Gigantidas species, six Bathymodiolus species, and two “Bathymodiolus” species, respectively. A Common interval Rearrangement Explorer (CREx) analysis revealed a gene order rearrangement in bathymodiolines that is distinct from that in other shallow-water mytilids. The CREx analysis also suggested that reversal, transposition, and tandem duplications with subsequent random gene loss (TDRL) may have been responsible for the evolution of mitochondrial gene orders in bathymodiolines. Moreover, a comparison of the mitogenomes of shallow-water and deep-sea mussels revealed that the latter lineage has experienced relaxed purifying selection, but 16 residues of the atp6, nad4, nad2, cob, nad5, and cox2 genes have underwent positive selection. Overall, this study provides new insights into the phylogenetic relationships and mitogenomic adaptations of deep-sea mussels

scholarly journals Bird Mitochondrial Gene Order: Insight from 3 Warbler Mitochondrial Genomes

2008 ◽  
Vol 25 (3) ◽  
pp. 475-477 ◽  
Author(s):  
Tiratha Raj Singh ◽  
Ophir Shneor ◽  
Dorothée Huchon
Keyword(s):  
Gene Order ◽  
Mitochondrial Gene ◽  
Mitochondrial Genomes ◽  
Mitochondrial Gene Order

scholarly journals Xenobiotic metabolism and its physiological consequences in high-Antarctic Notothenioid fishes

Polar Biology ◽  
2021 ◽  
Author(s):  
Anneli Strobel ◽  
Roger Lille-Langøy ◽  
Helmut Segner ◽  
Patricia Burkhardt-Holm ◽  
Anders Goksøyr ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Reporter Gene ◽  
Atlantic Cod ◽  
Antarctic Fish ◽  
Reporter Gene Assay ◽  
Antarctic Notothenioids ◽  
Isolated Liver Cells ◽  
Gene Assay ◽  
The Antarctic ◽  
Isolated Liver

AbstractThe Antarctic ecosystem is progressively exposed to anthropogenic contaminants, such as polycyclic aromatic hydrocarbons (PAHs). So far, it is largely unknown if PAHs leave a mark in the physiology of high-Antarctic fish. We approached this issue via two avenues: first, we examined the functional response of the aryl hydrocarbon receptor (Ahr), which is a molecular initiating event of many toxic effects of PAHs in biota. Chionodraco hamatus and Trematomus loennbergii served as representatives for high-Antarctic Notothenioids, and Atlantic cod, Gadus morhua as non-polar reference species. We sequenced and cloned the Ahr ligand binding domain (LBD) of the Notothenioids and deployed a GAL4-based luciferase reporter gene assay expressing the Ahr LBD. Benzo[a]pyrene (BaP), beta-naphthoflavone and chrysene were used as ligands for the reporter gene assay. Second, we investigated the energetic costs of Ahr activation in isolated liver cells of the Notothenioids during acute, non-cytotoxic BaP exposure. In the reporter assay, the Ahr LBD of Atlantic cod and the Antarctic Notothenioids were activated by the ligands tested herein. In the in vitro assays with isolated liver cells of high-Antarctic Notothenioids, BaP exposure had no effect on overall respiration, but caused shifts in the respiration dedicated to protein synthesis. Thus, our study demonstrated that high-Antarctic fish possess a functional Ahr that can be ligand-activated in a concentration-dependent manner by environmental contaminants. This is associated with altered cost for cellular protein synthesis. Future studies have to show if the toxicant-induced activation of the Ahr pathway may lead to altered organism performance of Antarctic fish.

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