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

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

Author(s):  
Chiara Papetti ◽  
Massimiliano Babbucci ◽  
Agnes Dettai ◽  
Andrea Basso ◽  
Magnus Lucassen ◽  
...  

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.


2010 ◽  
Vol 56 (1) ◽  
pp. 104-114 ◽  
Author(s):  
Julie Reveillaud ◽  
Thomas Remerie ◽  
Rob van Soest ◽  
Dirk Erpenbeck ◽  
Paco Cárdenas ◽  
...  

2020 ◽  
Vol 40 (12) ◽  
Author(s):  
Chenghao Jia ◽  
Xiumei Zhang ◽  
Shengyong Xu ◽  
Tianyan Yang ◽  
Takashi Yanagimoto ◽  
...  

Abstract Mitochondrial genome is a powerful molecule marker to provide information for phylogenetic relationships and revealing molecular evolution in ichthyological studies. Sebastiscus species, a marine rockfish, are of essential economic value. However, the taxonomic status and phylogenetic relationships of Sebastidae have been controversial so far. Here, the mitochondrial genomes (mitogenomes) of three species, S. tertius, S. albofasciatus, and S. marmoratus, were systemically investigated. The lengths of the mitogenomes’ sequences of S. tertius, S. albofasciatus, and S. marmoratus were 16910, 17056, and 17580 bp, respectively. It contained 13 protein-coding genes (PCGs), two ribosomal RNAs (rRNAs), 22 transfer RNA (tRNA) genes, and one identical control region (D-loop) among the three species. The genetic distance and Ka/Ks ratio analyses indicated 13 PCGs were suffering purifying selection and the selection pressures were different from certain deep-sea fishes, which were most likely due to the difference in their living environment. The phylogenetic tree was constructed by Bayesian Inference (BI) and Maximum Likelihood (ML). Most interestingly, the results indicated that Sebastidae and Scorpaenidae were grouped into a separate branch, so the taxonomic status of Sebastidae should be classified into subfamily Sebastinae. Our results may lead to a taxonomic revision of Scorpaenoidei.


2006 ◽  
Vol 8 (1) ◽  
pp. 43-63 ◽  
Author(s):  
Paul Roazen

George Wilbur, a pioneering Cape Cod psychoanalytic psychiatrist, was a longstanding editor of the journal American Imago, and an excellent source of information about the Viennese analysts Otto Rank and Hanns Sachs. Wilbur was also knowledgeable about the early reception of psychoanalysis in the Boston community.


Insects ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 668
Author(s):  
Tinghao Yu ◽  
Yalin Zhang

More studies are using mitochondrial genomes of insects to explore the sequence variability, evolutionary traits, monophyly of groups and phylogenetic relationships. Controversies remain on the classification of the Mileewinae and the phylogenetic relationships between Mileewinae and other subfamilies remain ambiguous. In this study, we present two newly completed mitogenomes of Mileewinae (Mileewa rufivena Cai and Kuoh 1997 and Ujna puerana Yang and Meng 2010) and conduct comparative mitogenomic analyses based on several different factors. These species have quite similar features, including their nucleotide content, codon usage of protein genes and the secondary structure of tRNA. Gene arrangement is identical and conserved, the same as the putative ancestral pattern of insects. All protein-coding genes of U. puerana began with the start codon ATN, while 5 Mileewa species had the abnormal initiation codon TTG in ND5 and ATP8. Moreover, M. rufivena had an intergenic spacer of 17 bp that could not be found in other mileewine species. Phylogenetic analysis based on three datasets (PCG123, PCG12 and AA) with two methods (maximum likelihood and Bayesian inference) recovered the Mileewinae as a monophyletic group with strong support values. All results in our study indicate that Mileewinae has a closer phylogenetic relationship to Typhlocybinae compared to Cicadellinae. Additionally, six species within Mileewini revealed the relationship (U. puerana + (M. ponta + (M. rufivena + M. alara) + (M. albovittata + M. margheritae))) in most of our phylogenetic trees. These results contribute to the study of the taxonomic status and phylogenetic relationships of Mileewinae.


Genes ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 1134
Author(s):  
Fei Ye ◽  
Hu Li ◽  
Qiang Xie

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.


1995 ◽  
Vol 69 (2) ◽  
pp. 376-380 ◽  
Author(s):  
Daniel B. Blake ◽  
Keith Sturgeon

Aldebarania arenitea (Astropectinidae; Asteroidea; Echinodermata) is described from the Rocky Point Member of the Maastrichtian (Upper Cretaceous) Peedee Formation of North Carolina. A turbulent, shallow-water environment is suggested by sedimentary features, a diverse marine fauna, and the morphology of Aldebarania. Aldebarania appears to be a partial ecological equivalent of living Astropecten and Luidia; however, phylogenetic relationships within the Astropectinidae are unstudied and the origin of similarities is unknown.


Author(s):  
Michel Praet-Van

This ultrastructural investigation of gametogenesis in a deep-sea anemone of the Bay of Biscay trawled around 2000 m depth, contributes to the knowledge of biology and strategy of reproduction of deep-sea benthos.This sea anemone is dioecious. The sperm appears very similar to those of shallow water sea anemones of the genus, Calliactis. The ultrastructural investigation of oogenesis allows the characteristics of the stages of previtellogenesis and vitellogenesis to be defined. The latter begins with a period of lipogenesis correlated with the formation of a trophonema. Mature oocytes measure up to 180 (im in diameter. Study of spermatogenesis and oogenesis reveals that spawning occurs in April/May. In males, the main area of testicular cysts, full of sperm, reaches maximal development from March to May and, in females, the percentage of mature oocytes decreases from 33% in April to 1% in May.Spawning may be induced by the advent in the deep-sea of the products of the spring phytoplankton bloom. This period of spawning, during the increased deposition of organic matter to the deep-sea floor, may be an advantageous strategy for early development of Paracalliactis.


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