scholarly journals Mitochondrial Genome Fragmentation Unites the Parasitic Lice of Eutherian Mammals

2018 ◽  
Vol 68 (3) ◽  
pp. 430-440 ◽  
Author(s):  
Fan Song ◽  
Hu Li ◽  
Guo-Hua Liu ◽  
Wei Wang ◽  
Peter James ◽  
...  
Keyword(s):  
Mitochondrial Genome ◽  
Genome Fragmentation

scholarly journals A single-cell genome reveals diplonemid-like ancestry of kinetoplastid mitochondrial gene structure

2019 ◽  
Vol 374 (1786) ◽  
pp. 20190100 ◽  
Author(s):  
Jeremy G. Wideman ◽  
Gordon Lax ◽  
Guy Leonard ◽  
David S. Milner ◽  
Raquel Rodríguez-Martínez ◽  
...  
Keyword(s):  
Mitochondrial Genome ◽  
Single Cell ◽  
Rna Editing ◽  
Phylogenetic Trees ◽  
Mitochondrial Gene ◽  
Mitochondrial Rna ◽  
Genome Fragmentation ◽  
Gene Architecture ◽  
Ancestral States ◽  
Cell Genome

Euglenozoa comprises euglenids, kinetoplastids, and diplonemids, with each group exhibiting different and highly unusual mitochondrial genome organizations. Although they are sister groups, kinetoplastids and diplonemids have very distinct mitochondrial genome architectures, requiring widespread insertion/deletion RNA editing and extensive trans -splicing, respectively, in order to generate functional transcripts. The evolutionary history by which these differing processes arose remains unclear. Using single-cell genomics, followed by small sub unit ribosomal DNA and multigene phylogenies, we identified an isolated marine cell that branches on phylogenetic trees as a sister to known kinetoplastids. Analysis of single-cell amplified genomic material identified multiple mitochondrial genome contigs. These revealed a gene architecture resembling that of diplonemid mitochondria, with small fragments of genes encoded out of order and or on different contigs, indicating that these genes require extensive trans -splicing. Conversely, no requirement for kinetoplastid-like insertion/deletion RNA-editing was detected. Additionally, while we identified some proteins so far only found in kinetoplastids, we could not unequivocally identify mitochondrial RNA editing proteins. These data invite the hypothesis that extensive genome fragmentation and trans -splicing were the ancestral states for the kinetoplastid-diplonemid clade but were lost during the kinetoplastid radiation. This study demonstrates that single-cell approaches can successfully retrieve lineages that represent important new branches on the tree of life, and thus can illuminate major evolutionary and functional transitions in eukaryotes. This article is part of a discussion meeting issue ‘Single cell ecology’.

scholarly journals Fragmentation in mitochondrial genomes in relation to elevated sequence divergence and extreme rearrangements

BMC Biology ◽  
2022 ◽  
Vol 20 (1) ◽  
Author(s):  
Shiqian Feng ◽  
Andrea Pozzi ◽  
Vaclav Stejskal ◽  
George Opit ◽  
Qianqian Yang ◽  
...  
Keyword(s):  
Mitochondrial Genome ◽  
Gene Order ◽  
Sequence Divergence ◽  
Purifying Selection ◽  
Protein Coding ◽  
High Conservation ◽  
Genome Fragmentation ◽  
Mt Genome ◽  
Very High ◽  
Gene Order Rearrangement

Abstract Background A single circular mitochondrial (mt) genome is a common feature across most metazoans. The mt-genome includes protein-coding genes involved in oxidative phosphorylation, as well as RNAs necessary for translation of mt-RNAs, whose order and number are highly conserved across animal clades, with few known exceptions of alternative mt-gene order or mt-genome architectures. One such exception consists of the fragmented mitochondrial genome, a type of genome architecture where mt-genes are split across two or more mt-chromosomes. However, the origins of mt-genome fragmentation and its effects on mt-genome evolution are unknown. Here, we investigate these origin and potential mechanisms underlying mt-genome fragmentation, focusing on a genus of booklice, Liposcelis, which exhibits elevated sequence divergence, frequent rearrangement of mt-gene order, and fragmentation of the mt genome, and compare them to other Metazoan clades. Results We found this genus Liposcelis exhibits very low conservation of mt-gene order across species, relative to other metazoans. Levels of gene order rearrangement were, however, unrelated to whether or not mt-genomes were fragmented or intact, suggesting mitochondrial genome fragmentation is not affecting mt-gene order directly. We further investigated possible mechanisms underpinning these patterns and revealed very high conservation of non-coding sequences at the edges of multiple recombination regions across populations of one particular Liposcelis species, supportive of a hypothesis that mt-fragmentation arises from recombination errors between mt-genome copies. We propose these errors may arise as a consequence of a heightened mutation rate in clades exhibiting mt-fragmentation. Consistent with this, we observed a striking pattern across three Metazoan phyla (Arthropoda, Nematoda, Cnidaria) characterised by members exhibiting high levels of mt-gene order rearrangement and cases of mt-fragmentation, whereby the mt-genomes of species more closely related to species with fragmented mt-genomes diverge more rapidly despite experiencing strong purifying selection. Conclusions We showed that contrary to expectations, mt-genome fragmentation is not correlated with the increase in mt-genome rearrangements. Furthermore, we present evidence that fragmentation of the mt-genome may be part of a general relaxation of a natural selection on the mt-genome, thus providing new insights into the origins of mt-genome fragmentation and evolution.

Understanding mitochondrial genome fragmentation in parasitic lice (Insecta: Phthiraptera)

2013 ◽  
Vol 35 (7) ◽  
pp. 847-855
Author(s):  
Wen-Ge DONG ◽  
Xian-Guo GUO ◽  
Dao-Chao JIN ◽  
Shi-Peng XUE ◽  
Feng QIN ◽  
...  
Keyword(s):  
Mitochondrial Genome ◽  
Genome Fragmentation

Human mitochondrial genome surgery

2018 ◽  
Vol XIII (3) ◽  
Author(s):  
I.О. Маzunin
Keyword(s):  
Mitochondrial Genome ◽  
Human Mitochondrial Genome
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