scholarly journals Investigation of Nucleotide Diversity Based on 17 Sea Cucumber Mitochondrial Genomes and Assessment of Sea Cucumber Mitochondrial Gene Markers

2021 ◽  
Vol 2 (5) ◽  
Author(s):  
Jongsun Park
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.


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.


2014 ◽  
Author(s):  
John Wares

There are well-known difficulties in using the cytochrome oxidase I (COI) mitochondrial gene region for population genetics and DNA barcoding in corals. A recent study of species divergence in the endemic Caribbean genus Agaricia reinforced such knowledge. However, the growing availability of whole mitochondrial genomes may help indicate more promising gene regions for species delineation. I assembled the whole mitochondrial genome for Agaricia fragilis from Illumina single-end 250bp reads and compared this sequence to that of the congener A. humilis. Although these data suggest that the cytochrome b (CYB) gene region is more promising, comparison of all available Scleractinian CYB sequence data indicates that multilocus approaches are still probably necessary for phylogenetic and population genetic analysis of recently-diverged coral taxa.


2018 ◽  
Author(s):  
Ji Haishuo ◽  
Xu Xiaofeng ◽  
Jin Xiufeng ◽  
Cheng Zhi ◽  
jin Hong ◽  
...  

In this study, we used a small RNA sequencing (sRNA-seq) based method to annotate the mitochondrial genome of the insect Erthesina fullo Thunberg at 1 bp resolution. Most of the new annotations were consistent with the previous annotations which were obtained using PacBio full-length transcripts. Two important findings are that animals transcribe both entire strands of mitochondrial genomes and the tandem repeat in the control region of the E. fullo mitochondrial genome contains the repeated Transcription Initiation Sites (TISs) of the H-strand. In addition, we found that the copy numbers of tandem repeats showed a great diversity within an individual, enriching the fundamental knowledge of mitochondrial biology. This sRNA-seq based method uses 5′ and 3′ end small RNAs to annotate nuclear non-coding and mitochondrial genes at 1 bp resolution and can also be used to identify new steady-state RNAs, particularly long non-coding RNAs (lncRNAs). Animal mitochondrial genomes containing one control region only encode two steady-state lncRNAs, which are the Mitochondrial D-loop 1 (MDL1) and its antisense gene (MDL1AS), while all other reported mitochondrial lncRNAs could be degraded fragments of transient RNAs or random breaks during experimental processing. The high-resolution annotations of mitochondrial genomes can be used to study the phylogenetics and molecular evolution of animals or to investigate mitochondrial gene transcription, RNA processing, RNA maturation and several other related topics.


Author(s):  
Yoh Ihara ◽  
Naoki Koike ◽  
Takafumi Nakano

The epigean spiders of the genus Cybaeus L. Koch, 1868 are known to have diversified in western North America and the Japanese Archipelago. To date, ~80 species of Cybaeus are known from Japan, but they have not previously been recorded from the Ryukyu Islands that harbour a diversity of endemic species. Here we describe eight new species of Cybaeus from the Ryukyu Islands, extending the range of Cybaeus southward to the central Ryukyus. Both sexes of each of the new species are described, and their phylogenetic relationships are estimated using nuclear and mitochondrial gene markers. Although Cybaeus okumurai, sp. nov. and C. kumadori, sp. nov. possess genital features that are common in the other Japanese congeners, the other six species (C. yakushimensis, sp. nov., C. kodama, sp. nov., C. amamiensis, sp. nov., C. aikana, sp. nov., C. tokunoshimensis, sp. nov., and C. hikidai, sp. nov.) are characterised by an elongated embolus and tubular spermathecae. These unique genital characteristics and the phylogeny recovered here suggest that these features evolved independently among the Japanese and Ryukyu Cybaeus species. Phylogenetic analyses highlight an unusual biogeographical pattern in which C. yakushimensis and C. kodama endemic to Yakushima Island in the northern Ryukyus are related to species distributed in the central Ryukyus. In contrast, our phylogeny suggests that C. okumurai from Tanegashima Island in the northern Ryukyus is sister to C. ashikitaensis (Komatsu, 1968), distributed in Kyushu of the Japanese Archipelago. The retreat constructs and sympatric distribution of Cybaeus found among the Ryukyus are also briefly discussed. ZooBank: urn:lsid:zoobank.org:pub:640D15AA-17F4-48EE-88B4-485CFF8FCD60


2018 ◽  
Vol 24 (2) ◽  
pp. 83
Author(s):  
Achmad Zamroni ◽  
Suwarso Suwarso ◽  
Arif Wibowo

Although the Longtail tuna (Thunnus tonggol) is an important fish in Indonesia, the population structure has not been investigated. In this study, the genetic differences in geographic scale are analyzed to provide a clear picture of the structure of T. tonggol populations along a transect stretching from Pemangkat (western Kalimantan) to Pekalongan in the Java Sea. We also analyzed SNPs in the mitochondrial 16S rRNA gene of T. tonggol as potential molecular marker for the identification of the origin within species. In total, three polymorphic sites (all represent singleton dimensions) were identified in the sequence analysis of the 570-bp fragment among a total of 97 T. tonggol individuals from Pekalongan and Pemangkat. Based on these polymorphic sites, four haplotypes were identified. The Pemangkat samples had higher amount of haplotype and nucleotide diversity (h = 0.1556 ± 0.0680 and  = 0.000277 ± 0.000432), meanwhile samples Pekalongan showed lower levels of diversity (h = 0.0400 ± 0.0380 and  = 0.000070 ± 0.000209). The study revealed a single, intermixing population of T. tonggol across the sampled location. No significant structuring was observed between other pairwise comparisons, indicating gene flow between geographically adjacent locations.


2017 ◽  
Vol 245 ◽  
pp. 34-38 ◽  
Author(s):  
Silvana Carnevale ◽  
Jorge Bruno Malandrini ◽  
María Laura Pantano ◽  
Claudia Cecilia Soria ◽  
Rosângela Rodrigues-Silva ◽  
...  

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