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 ◽  
...  

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.

2020 ◽  
Vol 20 (5) ◽  
Author(s):  
Jungmo Lee ◽  
Jonghyun Park ◽  
Hong Xi ◽  
Jongsun Park

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.


2018 ◽  
Author(s):  
Helen. E. Robertson ◽  
Philipp. H. Schiffer ◽  
Maximilian. J. Telford

AbstractThe Dicyemida and Orthonectida are two groups of tiny, simple, vermiform parasites that have historically been united in a group named the Mesozoa. Both Dicyemida and Orthonectida have just two cell layers and appear to lack any defined tissues. They were initially thought to be evolutionary intermediates between protozoans and metazoans but more recent analyses indicate that they are protostomian metazoans that have undergone secondary simplification from a complex ancestor. Here we describe the first almost complete mitochondrial genome sequence from an orthonectid, Intoshia linei, and describe nine and eight mitochondrial protein-coding genes from Dicyema sp. and Dicyema japonicum, respectively. The 14,247 base pair long I. linei sequence has typical metazoan gene content, but is exceptionally AT-rich, and has a divergent gene order compared to other metazoans. The data we present from the Dicyemida provide very limited support for the suggestion that dicyemid mitochondrial genes are found on discrete mini-circles, as opposed to the large circular mitochondrial genomes that are typical across the Metazoa. The cox1 gene from dicyemid species has a series of conserved in-frame deletions that is unique to this lineage. Using cox1 genes from across the genus Dicyema, we report the first internal phylogeny of this group.Key FindingsWe report the first almost-complete mitochondrial genome from an orthonectid parasite, Intoshia linei, including 12 protein-coding genes; 20 tRNAs and putative sequences for large and small subunit rRNAs. We find that the I. linei mitochondrial genome is exceptionally AT-rich and has a novel gene order compared to other published metazoan mitochondrial genomes. These findings are indicative of the rapid rate of evolution that has occurred in the I. linei mitochondrial genome.We also report nine and eight protein-coding genes, respectively, from the dicyemid species Dicyema sp. and Dicyema japonicum, and use the cox1 genes from both species for phylogenetic inference of the internal phylogeny of the dicyemids.We find that the cox1 gene from dicyemids has a series of four conserved in-frame deletions which appear to be unique to this group.


2018 ◽  
Vol 4 ◽  
Author(s):  
Helen E. Robertson ◽  
Philipp H. Schiffer ◽  
Maximilian J. Telford

Abstract The Dicyemida and Orthonectida are two groups of tiny, simple, vermiform parasites that have historically been united in a group named the Mesozoa. Both Dicyemida and Orthonectida have just two cell layers and appear to lack any defined tissues. They were initially thought to be evolutionary intermediates between protozoans and metazoans but more recent analyses indicate that they are protostomian metazoans that have undergone secondary simplification from a complex ancestor. Here we describe the first almost complete mitochondrial genome sequence from an orthonectid, Intoshia linei, and describe nine and eight mitochondrial protein-coding genes from Dicyema sp. and Dicyema japonicum, respectively. The 14 247 base pair long I. linei sequence has typical metazoan gene content, but is exceptionally AT-rich, and has a unique gene order. The data we have analysed from the Dicyemida provide very limited support for the suggestion that dicyemid mitochondrial genes are found on discrete mini-circles, as opposed to the large circular mitochondrial genomes that are typical of the Metazoa. The cox1 gene from dicyemid species has a series of conserved, in-frame deletions that is unique to this lineage. Using cox1 genes from across the genus Dicyema, we report the first internal phylogeny of this group.


2014 ◽  
Vol 6 (12) ◽  
pp. 3326-3343 ◽  
Author(s):  
Massimiliano Babbucci ◽  
Andrea Basso ◽  
Antonio Scupola ◽  
Tomaso Patarnello ◽  
Enrico Negrisolo

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

Author(s):  
Xiao-Long Yuan ◽  
Min Cao ◽  
Guo-Ming Shen ◽  
Huai-Bao Zhang ◽  
Yong-Mei Du ◽  
...  

In tobacco plants, symbiont endophytic fungi are widely distributed in all tissues where they play important roles. It is therefore important to determine the species distribution and characteristics of endophytic fungi in tobacco. Here, two parasitic fungi Leptosphaerulina chartarum and Curvularia trifolii were isolated and identified from normal tobacco tissue. We sequenced the mitogenomes of these two species and analysed their features, gene content, and evolutionary histories. The L. chartarum and C. trifolii mitochondrial genomes were 68,926 bp and 59,100 bp long circular molecules with average GC contents of 28.60% and 29.31%, respectively. The L. chartarum mitogenome contained 36 protein coding genes, 26 tRNA genes, and 2 rRNA genes (rrnL and rrnS), which were located on both strands. The C. trifolii mitogenome contained 26 protein coding genes, 29 tRNA genes, and 2 rRNA genes (rrnL and rrnS). The L. chartarum 26 tRNAs ranged from 70 bp to 84 bp in length, whereas the 29 tRNAs in C. trifolii ranged from 71 bp to 85 bp. L. chartarum and C. trifolii mtDNAs had an identical mitochondrial gene order and orientation and were phylogenetically identified as sisters. These data therefore provide an understanding of the gene content and evolutionary history of species within Pleosporales.


2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Dianhang Jiang ◽  
Xiaodong Zheng ◽  
Xiaoqi Zeng ◽  
Lingfeng Kong ◽  
Qi Li

AbstractThe complete mitochondrial genomes of Harpago chiragra and Lambis lambis (Strombidae) were determined with the size of 15,460 bp and 15,481 bp, respectively, and both sequences contained 13 protein-coding genes, 22 tRNAs, and two rRNAs. H. chiragra and L. lambis have similar mitochondrial features, corresponding to typical gastropod mitochondrial genomes, such as the conserved gene order, a high A + T content (66.22% for H. chiragra and 66.10% for L. lambis), and preference for A + T-rich codons. The start or termination codon of same protein-coding gene in H. chiragra was consistent with that in L. lambis, except for the termination codon of cox1 gene (TAG for H. chiragra and TAA for L. lambis) and the start codon of nad4 (GTG for H. chiragra and ATG for L. lambis). Pairwise sequence alignments detected different degrees of variations in H. chiragra and L. lambis mitochondrial genomes; and the two species had lower levels of genetic distance (0.202 for nucleotide sequence) and closest relationships as compared to Strombus gigas and Oncomelania hupensis. The 13 partitioned nucleotide sequences of protein coding genes of H. chiragra and L. lambis were aligned with representatives of the main lineages of gastropods and their phylogenetic relationships were inferred. H. chiragra and L. lambis share the same gene order as Littorinimorpha species, except Vermetoidea, which demonstrate a gene rearrangement in species. The reconstructed phylogeny supports three major clades within Littorinimorpha: 1) Stromboidea, Tonnoidea, Littorinoidea, and Naticoidea, 2) Rissooidea and Truncatelloidea, and 3) Vermetoidea. In addition, a relaxed molecular clock calibrated with fossils dated the diversification of Strombidae near 112 (44–206) Mya and a possible radiation is detected to occur between 45–75 Mya, providing implications to understand the Cenozoic replacement event (65–135 Mya) of Aporrhaidae by Strombidae.


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.


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