scholarly journals Mitogenomics of Perumytilus purpuratus (Bivalvia: Mytilidae) and its implications for doubly uniparental inheritance of mitochondria

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5593 ◽  
Author(s):  
Beata Śmietanka ◽  
Marek Lubośny ◽  
Aleksandra Przyłucka ◽  
Karin Gérard ◽  
Artur Burzyński

Animal mitochondria are usually inherited through the maternal lineage. The exceptional system allowing fathers to transmit their mitochondria to the offspring exists in some bivalves. Its taxonomic spread is poorly understood and new mitogenomic data are needed to fill the gap. Here, we present for the first time the two divergent mitogenomes from Chilean mussel Perumytilus purpuratus. The existence of these sex-specific mitogenomes confirms that this species has the doubly uniparental inheritance (DUI) of mitochondria. The genetic distance between the two mitochondrial lineages in P. purpuratus is not only much bigger than in the Mytilus edulis species complex but also greater than the distance observed in Musculista senhousia, the only other DUI-positive member of the Mytilidae family for which both complete mitochondrial genomes were published to date. One additional, long ORF (open reading frame) is present exclusively in the maternal mitogenome of P. purpuratus. This ORF evolves under purifying selection, and will likely be a target for future DUI research.




Author(s):  
Donald T. Stewart ◽  
Chloe M. Stephenson ◽  
Ljiljana M. Stanton ◽  
Emily E. Chase ◽  
Brent M. Robicheau ◽  
...  

Many freshwater mussels (Order Unionida) have an unusual system of doubly uniparental inheritance (DUI) of mitochondrial (mt) DNA. In species with DUI, males possess a female-transmitted (F-type) mt genome and a male-transmitted (M-type) mt genome. These genomes contain non-canonical open reading frame (orf) genes referred to as f-orf and m-orf, present in F and M mt genomes, respectively. These genes have been implicated in sexual development in Unionida. When gonochoric species become hermaphroditic, which has happened several times in Unionida, they lose their M-type mt genome, and f-orf genes evolve dramatically. Resulting F-ORF proteins are highly divergent in terms of primary nucleotide sequence, inferred amino acids, and hydrophobic properties; these genes (and proteins) are referred to as hermaphroditic orfs or h-orfs (and H-ORFs). We investigated patterns of hydrophobicity divergence for H-ORF proteins in hermaphrodites versus F-ORF proteins in closely related gonochoric species against cytochrome c oxidase subunit 1 (cox1) divergences. This approach was used to assess whether cryptic hermaphrodites can be detected. Although we did not detect evidence for the recent transition of any populations of Eastern Floaters, Pyganodon cataracta (Say, 1817) to hermaphroditism, our analyses demonstrate that molecular signatures in mtDNA can be used to detect hermaphroditism in freshwater mussels.



2020 ◽  
Vol 21 (5) ◽  
pp. 1874 ◽  
Author(s):  
Huiting Ruan ◽  
Min Li ◽  
Zhenhai Li ◽  
Jiajie Huang ◽  
Weiyuan Chen ◽  
...  

Mitochondrial genome is a powerful molecule marker to explore phylogenetic relationships and reveal molecular evolution in ichthyological studies. Gerres species play significant roles in marine fishery, but its evolution has received little attention. To date, only two Gerres mitochondrial genomes were reported. In the present study, three mitogenomes of Gerres (Gerres filamentosus, Gerres erythrourus, and Gerres decacanthus) were systemically investigated. The lengths of the mitogenome sequences were 16,673, 16,728, and 16,871 bp for G. filamentosus, G. erythrourus, and G. decacanthus, respectively. Most protein-coding genes (PCGs) were initiated with the typical ATG codon and terminated with the TAA codon, and the incomplete termination codon T/TA could be detected in the three species. The majority of AT-skew and GC-skew values of the 13 PCGs among the three species were negative, and the amplitude of the GC-skew was larger than the AT-skew. 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, were which most likely due to the difference in their living environment. The phylogenetic tree was constructed by molecular method (Bayesian Inference (BI) and maximum Likelihood (ML)), providing further supplement to the scientific classification of fish. Three Gerres species were differentiated in late Cretaceous and early Paleogene, and their evolution might link with the geological events that could change their survival environment.



2017 ◽  
Author(s):  
Arunas L Radzvilavicius ◽  
Hanna Kokko ◽  
Joshua Christie

AbstractMitochondria are ATP-producing organelles of bacterial ancestry that played a key role in the origin and early evolution of complex eukaryotic cells. Most modern eukaryotes transmit mitochondrial genes uniparentally, often without recombination among genetically divergent organelles. While this asymmetric inheritance maintains the efficacy of purifying selection at the level of the cell, the absence of recombination could also make the genome susceptible to Muller’s ratchet. How mitochondria escape this irreversible defect accumulation is a fundamental unsolved question. Occasional paternal leakage could in principle promote recombination, but it would also compromise the purifying-selection benefits of uniparental inheritance. We assess this tradeoff using a stochastic population-genetic model. In the absence of recombination, uniparental inheritance of freely segregating genomes mitigates mutational erosion, while paternal leakage exacerbates the ratchet effect. Mitochondrial fusion-fission cycles ensure independent genome segregation, improving purifying selection. Paternal leakage provides opportunity for recombination to slow down the mutation accumulation, but always at a cost of increased steady-state mutation load. Our findings indicate that random segregation of mitochondrial genomes under uniparental inheritance can effectively combat the mutational meltdown, and that homologous recombination under paternal leakage might not be needed.



2020 ◽  
Author(s):  
Miguel Camacho-Sanchez ◽  
Jennifer A Leonard

Abstract Tropical mountains are cradles of biodiversity and endemism. Sundaland, tropical Southeast Asia, hosts 3 species of Rattus endemic to elevations above 2000 m with an apparent convergence in external morphology: Rattus korinchi and R. hoogerwerfi from Sumatra, and R. baluensis from Borneo. A fourth one, R. tiomanicus, is restricted to lowland elevations across the whole region. The origins of these endemics are little known due to the absence of a robust phylogenetic framework. We use complete mitochondrial genomes from the 3 high altitude Rattus, and several related species to determine their relationships, date divergences, reconstruct their history of colonization, and test for selection on the mitochondrial DNA. We show that mountain colonization happened independently in Borneo (<390 Kya) and Sumatra (~1.38 Mya), likely from lowland lineages. The origin of the Bornean endemic R. baluensis is very recent and its genetic diversity is nested within the diversity of R. tiomanicus. We found weak evidence of positive selection in the high-elevation lineages and attributed the greater nonsynonymous mutations on these branches (specially R. baluensis) to lesser purifying selection having acted on the terminal branches in the phylogeny.



Genetics ◽  
2003 ◽  
Vol 164 (2) ◽  
pp. 603-611 ◽  
Author(s):  
Marco Passamonti ◽  
Jeffrey L Boore ◽  
Valerio Scali

Abstract Doubly uniparental inheritance (DUI) provides an intriguing system for addressing aspects of molecular evolution and intermolecular recombination of mitochondrial DNA. For this reason, a large sequence analysis has been performed on Tapes philippinarum (Bivalvia, Veneridae), which has mitochondrial DNA heteroplasmy that is consistent with a DUI. The sequences of a 9.2-kb region (containing 29 genes) from 9 individuals and the sequences of a single gene from another 44 individuals are analyzed. Comparisons suggest that the two sex-related mitochondrial genomes do not experience a neutral pattern of divergence and that selection may act with varying strength on different genes. This pattern of evolution may be related to the long, separate history of M and F genomes within their tissue-specific “arenas.” Moreover, our data suggest that recombinants, although occurring in soma, may seldom be transmitted to progeny in T. philippinarum.



PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e12465
Author(s):  
Nian Gong ◽  
Lin Yang ◽  
Xiangsheng Chen

Here, the complete mitochondrial genomes (mitogenomes) of 12 Caliscelidae species, Augilina tetraina, Augilina triaina, Symplana brevistrata, Symplana lii, Neosymplana vittatum, Pseudosymplanella nigrifasciata, Symplanella brevicephala, Symplanella unipuncta, Augilodes binghami, Cylindratus longicephalus, Caliscelis shandongensis, and Peltonotellus sp., were determined and comparatively analyzed. The genomes varied from 15,424 to 16,746 bp in size, comprising 37 mitochondrial genes and an A+T-rich region. The typical gene content and arrangement were similar to those of most Fulgoroidea species. The nucleotide compositions of the mitogenomes were biased toward A/T. All protein-coding genes (PCGs) started with a canonical ATN or GTG codon and ended with TAN or an incomplete stop codon, single T. Among 13 PCGs in 16 reported Caliscelidae mitogenomes, cox1 and atp8 showed the lowest and highest nucleotide diversity, respectively. All PCGs evolved under purifying selection, with atp8 considered a comparatively fast-evolving gene. Phylogenetic relationships were reconstructed based on 13 PCGs in 16 Caliscelidae species and five outgroups using maximum likelihood and Bayesian inference analyses. All species of Caliscelidae formed a steadily monophyletic group with high support. Peltonotellini was present at the basal position of the phylogenetic tree. Augilini was the sister group to Caliscelini and Peltonotellini.



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