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The barn swallow (Hirundo rustica) poses a number of fascinating scientific questions, including the taxonomic status of postulated subspecies. Here, we obtained and assessed the sequence variation of 411 complete mitogenomes, mainly from the European H. r. rustica, but other subspecies as well. In almost every case, we observed subspecies-specific haplogroups, which we employed together with estimated radiation times to postulate a model for the geographical and temporal worldwide spread of the species. The female barn swallow carrying the Hirundo rustica ancestral mitogenome left Africa (or its vicinity) around 280 thousand years ago (kya), and her descendants expanded first into Eurasia and then, at least 51 kya, into the Americas, from where a relatively recent (<20 kya) back migration to Asia took place. The exception to the haplogroup subspecies specificity is represented by the sedentary Levantine H. r. transitiva that extensively shares haplogroup A with the migratory European H. r. rustica and, to a lesser extent, haplogroup B with the Egyptian H. r. savignii. Our data indicate that rustica and transitiva most likely derive from a sedentary Levantine population source that split at the end of the Younger Dryas (YD) (11.7 kya). Since then, however, transitiva received genetic inputs from and admixed with both the closely related rustica and the adjacent savignii. Demographic analyses confirm this species’ strong link with climate fluctuations and human activities making it an excellent indicator for monitoring and assessing the impact of current global changes on wildlife.

This study reports the complete mitochondrial genome (15,610 bp) of , a grasshopper species from Xinjiang, China, which comprises 13 protein-coding genes, 2 rRNA genes, 22 tRNA genes, and a control region. Phylogenetic analysis confirms its close evolutionary relationship with the genera and , supporting its placement within the tribe Gomphocerini. These findings enrich the available mitochondrial genome resources for grasshoppers and provide valuable molecular data for subsequent research on the phylogeny and evolutionary history of the subfamily Gomphocerinae.

Background : The intimate association between parasitic plants and their hosts favours the exchange of genetic material, potentially leading to horizontal gene transfer (HGT) between plants. With the recent publication of several parasitic plant nuclear genomes, there has been considerable focus on such non-sexual exchange of genes. To enhance the picture on HGT events in a widely distributed parasitic genus, Cuscuta (dodders), we assembled and analyzed the organellar genomes of two recently sequenced species, C. australis and C. campestris , making this the first account of complete mitochondrial genomes (mitogenomes) for this genus. Results : The mitogenomes are 265,696 and 275,898 bp in length and contain a typical set of mitochondrial genes, with 10 missing or pseudogenized genes often lost from angiosperm mitogenomes. Each mitogenome also possesses a structurally unusual ccmF(C) gene, which exhibits splitting of one exon and a shift to trans-splicing of its intron. Based on phylogenetic analysis of mitochondrial genes from across angiosperms and similarity-based searches, there is little to no indication of HGT into the Cuscuta mitogenomes. A few candidate regions for plastome-to-mitogenome transfer were identified, with one suggestive of possible HGT. Conclusions : The lack of HGT is surprising given examples from the nuclear genomes, and may be due in part to the relatively small size of the Cuscuta mitogenomes, limiting the capacity to integrate foreign sequences.

The complete mitochondrial genome of the Lutjanus ehrenbergii was sequenced by Sanger platform. The circular mitogenome of L. ehrenbergii (16,512 bp) encoded the typical 37 genes, and one non-coding regions. All of the protein-encoding genes were located on the H chain except ND6. The nucleotide composition was A (28.04%), T (24.84%), C (30.89%) and G (16.23%). Phylogenetic analysis based on the 13PCGs sequences showed that L. ehrenbergii was closely related to the sister species of Lutjanus russellii and Lutjanus carponotatus. These studies provided important mitochondrial genome data of L. ehrenbergii, phylogenetic tree analysis revealed the position of L. ehrenbergii in Lutjaniformes.

GetOrganelle is a state-of-the-art toolkit to accurately assemble organelle genomes from whole genome sequencing data. It recruits organelle-associated reads using a modified “baiting and iterative mapping” approach, conducts de novo assembly, filters and disentangles the assembly graph, and produces all possible configurations of circular organelle genomes. For 50 published plant datasets, we are able to reassemble the circular plastomes from 47 datasets using GetOrganelle. GetOrganelle assemblies are more accurate than published and/or NOVOPlasty-reassembled plastomes as assessed by mapping. We also assemble complete mitochondrial genomes using GetOrganelle. GetOrganelle is freely released under a GPL-3 license ( https://github.com/Kinggerm/GetOrganelle ).

Background  PacBio high fidelity (HiFi) sequencing reads are both long (15–20 kb) and highly accurate (> Q20). Because of these properties, they have revolutionised genome assembly leading to more accurate and contiguous genomes. In eukaryotes the mitochondrial genome is sequenced alongside the nuclear genome often at very high coverage. A dedicated tool for mitochondrial genome assembly using HiFi reads is still missing. Results  MitoHiFi was developed within the Darwin Tree of Life Project to assemble mitochondrial genomes from the HiFi reads generated for target species. The input for MitoHiFi is either the raw reads or the assembled contigs, and the tool outputs a mitochondrial genome sequence fasta file along with annotation of protein and RNA genes. Variants arising from heteroplasmy are assembled independently, and nuclear insertions of mitochondrial sequences are identified and not used in organellar genome assembly. MitoHiFi has been used to assemble 374 mitochondrial genomes (368 Metazoa and 6 Fungi species) for the Darwin Tree of Life Project, the Vertebrate Genomes Project and the Aquatic Symbiosis Genome Project. Inspection of 60 mitochondrial genomes assembled with MitoHiFi for species that already have reference sequences in public databases showed the widespread presence of previously unreported repeats. Conclusions  MitoHiFi is able to assemble mitochondrial genomes from a wide phylogenetic range of taxa from Pacbio HiFi data. MitoHiFi is written in python and is freely available on GitHub ( https://github.com/marcelauliano/MitoHiFi ). MitoHiFi is available with its dependencies as a Docker container on GitHub (ghcr.io/marcelauliano/mitohifi:master).

Teinopalpus aureus Mell (Lepidoptera: Papilionidae) is distributed throughout China, Vietnam and Laos, and is listed as a Class I species in China. To identify whether the exuviae of larva is belonging to Teinopalpus aureus Mell, 1923 or not, and to compare the gene structure and genetic differences among the known populations, ten mitogenomes of T. aureus from the exuviae of larva collected in the Michelia maudiae were sequenced. This method of sequencing the mitogenomes of exuviae of larva can give us the chance to monitor the conservation of rare butterflies. Ten mitogenomes of T. aureus showed typical gene arrangements and contained 13 protein-coding genes (PCGs), two ribosomal RNA genes (12S rRNA and 16S rRNA), 22 transfer RNA (tRNA) genes, and a non-coding control region (D-loop). The two haplotypes with one base different in T. aureus were found. We also conducted phylogenetic analyses including all different populations of T. aureus to assess the phylogenetic relationship of T. aureus. The lengths of the 12S rRNA and 16S rRNA genes from both haplotypes were 776 base pairs (bp) and 1,334 bp, respectively. The genetic distance of the ten samples was calculated as 0-0.000065 on the basis of the whole mitogenomes. T. aureus found in Taishun, Zhejiang province, China had a close phylogenetic relationship with the clade of T. aureus found in Pingshan, Jiangxi province, China, which was supported by neighbour-joining analysis.

We, the Editor, authors and Publisher of Mitochondrial DNA Part B: Resources, have retracted the following article: Qiang Li, Xin Jin, Zuqin Chen, Chuan Xiong, Ping Li & Wenli Huang (2019) 'Characterization of the complete mitochondrial genome of an important edible fungus Auricularia Polytricha' 4:1, 1107-1108, DOI https://doi.org/10.1080/23802359.2019.1586494 . This article has been retracted at the request of the authors as, subsequent to publication, it has been identified that the species reported in the article is incorrect. The species should be Suillus sp. and not Auricularia polytricha as reported. The article has therefore been retracted as the data reported in the article are inaccurate. We have been informed in our decision-making by our policy on publishing ethics and integrity and the COPE guidelines on retractions. The retracted article will remain online to maintain the scholarly record, but it will be digitally watermarked on each page as \"Retracted\".

In the present research, the mitochondrial genome of Ephemera serica was sequenced through next generation sequencing methods and its phylogenetic position in Ephemeroptera was analyzed. Total mitochondrial genome is 15,004 bp in length, and contains 13 protein coding genes, two ribosomal RNA genes, and 22 transfer RNA genes. Mitogenomic phylogeny trees were constructed including 45 species from 13 families. The results show that E. serica is closely related to E. rufomaculata.

Gastrodia pubilabiata is a nonphotosynthetic and mycoheterotrophic orchid belonging to subfamily Epidendroideae. Compared to other typical angiosperm species, the plastome of G. pubilabiata is dramatically reduced in size to only 30,698 base pairs (bp). This reduction has led to the loss of most photosynthesis-related genes and some housekeeping genes in the plastome, which now only contains 19 protein coding genes, three tRNAs, and three rRNAs. In contrast, the typical orchid species contains 79 protein coding genes, 30 tRNAs, and four rRNAs. This study decoded the entire mitogenome of G. pubilabiata, which consisted of 44 contigs with a total length of 867,349 bp. Its mitogenome contained 38 protein coding genes, nine tRNAs, and three rRNAs. The gene content of G. pubilabiata mitogenome is similar to the typical plant mitogenomes even though the mitogenome size is twice as large as the typical ones. To determine possible gene transfer events between the plastome and the mitogenome individual BLASTN searches were conducted, using all available orchid plastome sequences and flowering plant mitogenome sequences. Plastid rRNA fragments were found at a high frequency in the mitogenome. Seven plastid protein coding gene fragments (ndhC, ndhJ, ndhK, psaA, psbF, rpoB, and rps4) were also identified in the mitogenome of G. pubilabiata. Phylogenetic trees using these seven plastid protein coding gene fragments suggested that horizontal gene transfer (HGT) from plastome to mitogenome occurred before losses of photosynthesis related genes, leading to the lineage of G. pubilabiata. Compared to species phylogeny of the lineage of orchid, it was estimated that HGT might have occurred approximately 30 million years ago.