Mitochondrial Genome Data Research Articles

Characterization, Comparison of Four New Mitogenomes of Centrotinae (Hemiptera: Membracidae) and Phylogenetic Implications Supports New Synonymy.

To explore the phylogenetic relationships of the subfamily Centrotinae from the mitochondrial genome data, four complete mitogenomes (Anchon lineatus, Anchon yunnanensis, Gargara genistae and Tricentrus longivalvulatus) were sequenced and analyzed. All the newly sequenced mitogenomes contain 37 genes. Among the 13 protein-coding genes (PCGs) of the Centrotinae mitogenomes, a sliding window analysis and the ratio of Ka/Ks suggest that atp8 is a relatively fast evolving gene, while cox1 is the slowest. All PCGs start with ATN, except for nad5 (start with TTG), and stop with TAA or the incomplete stop codon T, except for nad2 and cytb (terminate with TAG). All tRNAs can fold into the typical cloverleaf secondary structure, except for trnS1, which lacks the dihydrouridine (DHU) arm. The BI and ML phylogenetic analyses of concatenated alignments of 13 mitochondrial PCGs among the major lineages produce a well-resolved framework. Phylogenetic analyses show that Membracoidea, Smiliinae and Centrotinae, together with tribes Centrotypini and Leptobelini are recovered as well-supported monophyletic groups. The tribe Gargarini (sensu Wallace et al.) and its monophyly are supported.

Tracing the evolution of bioluminescent light organs across the deep-sea shrimp family Sergestidae using a genomic skimming and phylogenetic approach

Deep-sea shrimp of the family Sergestidae Dana, 1852 provide a unique system for studying the evolution of bioluminescence. Most species within the family possess autogenic bioluminescent photophores in one of three distinct forms: lensed photophores; non-lensed photophores; or internal organs of Pesta. This morphological diversity across the Sergestidae has resulted in recent major taxonomic revisions, dividing the two major genera (Sergia Stimpson, 1860 and Sergestes Milne Edwards, 1830) into 15. The present study capitalises on molecular data to construct an updated genus-level phylogeny of sergestid shrimp. DNA was successfully extracted from ~87 individuals belonging to 13 of the 15 newly proposed genera. A ‘genome skimming’ approach was implemented, allowing the capture of mitochondrial genomic data across 19 sergestid species. Additional individuals have been incorporated into the phylogeny through Sanger sequencing of both nuclear (H3 and NAK) and mitochondrial (16S and COI) genes. The resulting molecular phylogeny is compared with previous morphological trees with specific attention to genus-level relationships. The -sergestes group was rendered non-monophyletic and the -sergia group was recovered as monophyletic. Ancestral state reconstructions of light organ type indicate that organs of Pesta is the ancestral state for the family. Non-lensed photophores evolved once across the -sergia group, but were later lost in the deepest living genus, Sergia. Lensed photophores also evolved once within the genera Prehensilosergia Vereshchaka, Olesen & Lunina, 2014, Lucensosergia Vereshchaka, Olesen & Lunina, 2014 and Challengerosergia Vereshchaka, Olesen & Lunina, 2014. These findings identify preliminary patterns across light organ type and species’ depth distributions; however, future research that incorporates finer-scale depth data and more species is needed to confirm our findings.

Towards resolving taxonomic uncertainties in wolf, dog and jackal lineages of Africa, Eurasia and Australasia

AbstractSuccessful conservation depends on accurate taxonomy. Currently, the taxonomy of canids in Africa, Eurasia and Australasia is unstable as recent molecular and morphological studies have questioned earlier phenetic classifications. We review available information on several taxa of Old World and Australasian Canis with phylogenetic uncertainties (namely, African jackals, Asian wolves and Australasian dogs), in order to assess the validity of suggested scientific names and provide a scientific basis for reaching a taxonomic consensus primarily based on molecular data, but also including morphology, biogeography and behavioural ecology. We identify major knowledge gaps, provide recommendations for future research and discuss conservation implications of an updated taxonomic framework. Recent molecular studies indicate that the former Afro‐Eurasian ‘golden jackal’ represents two distinct lineages, the golden jackal (Canis aureus) from Eurasia and the African wolf (C. lupaster) from Africa. Phylogenetic research also indicates that the side‐striped and black‐backed jackals form a monophyletic group that branched earlier than Canis, Cuon and Lycaon, which should be reassigned to the genus Lupulella as L. adusta and L. mesomelas, respectively. The Himalayan/Tibetan and Indian wolf lineages appear to have diverged earlier and are distinct from all other grey wolves (C. lupus) based on mitochondrial and nuclear genome data. However, until genome‐wide data from multiple individuals across the range clarify relationships with other taxa, we suggest referring to the Himalayan/Tibetan wolf lineage as Canis lupus chanco. We support the currently accepted nomenclature for the Indian wolf Canis lupus pallipes for the wolf populations found on the Indian subcontinent and possibly also in south‐western Asia (exact geographical boundary pending). The information presented here provides a current and consistent taxonomic framework for use by conservationists and other practitioners, but it is also intended to stimulate further research to resolve current uncertainties affecting the taxonomy of Old World canids.

Phylogeographic study using nuclear genome sequences of <i>Asip</i> to infer the origins of ventral fur color variation in the house mouse <i>Mus musculus</i>

While the house mouse (Mus musculus), widely distributed in Eurasia, is known to have substantial coat color variation between and within local populations, in both primary and secondary distribution areas, including the Japanese archipelago, the evolutionary history of the color variation is poorly understood. To address the ventral fur color variation, we quantified the lightness of museum skin specimens, and found that the southern subspecies, M. m. castaneus (CAS), has high and low lightness in dry and rainy geographic regions, respectively. The northern subspecies, M. m. musculus (MUS), has low and high levels of lightness in the high and middle latitudes of northern Eurasia, respectively. We examined sequence variation of the agouti signaling protein gene (Asip), which is known to be responsible for the ventral fur color. We performed phylogenetic analyses with 196 haplotype sequences of Asip (~180 kb) generated by phasing the whole-genome data of 98 wild mice reported previously. Network and phylogenetic tree construction revealed clustering of haplotypes representing the two subspecies, MUS and CAS. A number of subclusters with geographic affinities appeared within the subspecies clusters, in which the essential results were consistent with those reconstructed with whole mitochondrial genome data, indicating that the phased haplotype genome sequences of the nuclear genome can be a useful tool for tracing the dispersal of geographical lineages. The results of phylogeographic analysis showed that CAS mice with darker ventral fur possessed similar Asip haplotypes across the geographic distribution, suggesting that these haplotypes are major causes of the historical introduction of Asip haplotypes for darker ventral fur in mice from northern India to the peripheral areas, including the Japanese archipelago. Similarly, MUS in East Asia, which has a white abdomen, formed an Asip haplogroup with that from northern Iran, also with a white abdomen.

Lions and brown bears colonized North America in multiple synchronous waves of dispersal across the Bering Land Bridge.

The Bering Land Bridge connecting North America and Eurasia was periodically exposed and inundated by oscillating sea levels during the Pleistocene glacial cycles. This land connection allowed the intermittent dispersal of animals, including humans, between Western Beringia (far northeast Asia) and Eastern Beringia (northwest North America), changing the faunal community composition of both continents. The Pleistocene glacial cycles also had profound impacts on temperature, precipitation and vegetation, impacting faunal community structure and demography. While these palaeoenvironmental impacts have been studied in many large herbivores from Beringia (e.g., bison, mammoths, horses), the Pleistocene population dynamics of the diverse guild of carnivorans present in the region are less well understood, due to their lower abundances. In this study, we analyse mitochondrial genome data from ancient brown bears (Ursus arctos; n=103) and lions (Panthera spp.; n=39), two megafaunal carnivorans that dispersed into North America during the Pleistocene. Our results reveal striking synchronicity in the population dynamics of Beringian lions and brown bears, with multiple waves of dispersal across the Bering Land Bridge coinciding with glacial periods of low sea levels, as well as synchronous local extinctions in Eastern Beringia during Marine Isotope Stage 3. The evolutionary histories of these two taxa underline the crucial biogeographical role of the Bering Land Bridge in the distribution, turnover and maintenance of megafaunal populations in North America.

Complete mitochondrial genomes of four species of praying mantises (Dictyoptera, Mantidae) with ribosomal second structure, evolutionary and phylogenetic analyses.

Praying mantises are distributed all over the world. Though some Mantodea mitogenomes have been reported, an evolutionary genomic and phylogenetic analysis study lacks the latest taxonomic system. In the present study, four new mitogenomes were sequenced and annotated. Deroplatys truncate, D. lobate, Amorphoscelis chinensis and Macromantis sp. belong to Deroplatyidae, Amorphoscelidae and Photinaidae family, respectively. Our results indicated that the ATP8 gene may be lost in D. truncate and D. lobata mt genome, and four tRNA genes have not been found in D. truncate, D. lobata and Macromantis sp. A dN/dS pair analysis was conducted and it was found that all genes have evolved under purifying selection. Furthermore, we tested the phylogenetic relationships between the eight families of the Mantodea, including 35 species of praying Mantis. Based on the complete mitochondrial genome data, it was also suggested as sister to Deroplatyidae + Mantidae, Metallyticus sp., the only representative of Metallyticidae, is sister to the remaining mantises. Our results support the taxonomic system of Schwarz and Roy and are consistent with previous studies.

Whole mitochondrial genomes assembled from thermally altered forensic bones and teeth

The recovery and analysis of genetic material obtained from thermally altered human bones and teeth are increasingly important to forensic investigations, especially in cases where soft-tissue identification is no longer possible. Although little is known about how these fire-related processes affect DNA degradation over time, next-generation sequencing technology in combination with traditional osteobiographical applications may provide us clues to these questions. In this study, we compare whole mitochondrial genome data generated using two different DNA extraction methods from 27 thermally altered samples obtained from fire victims (Maricopa County, Arizona) . DNA extracts were converted to double-stranded DNA libraries and enriched for whole mitochondrial DNA (mtDNA) using synthetic biotinylated RNA baits, then sequenced on an Illumina MiSeq. We processed the mitochondrial data using an in-house computational pipeline (MitoPipe1.0) composed of ancient DNA and modern genomics applications, then compared the resulting information across the two extraction types and five burn categories. Our analysis shows that DNA fragmentation increases with temperature, but that the acute insult from fire combined with the lack of water is insufficient to produce 5′ and 3′ terminal deamination characteristic of ancient DNA. Our data also suggest an acute and significant point of DNA degradation between 350 °C and 550 °C, and that the likelihood of generating high quality mtDNA haplogroup calls decreases significantly at temperatures > 550 °C. This research is part of a concerted effort to understand how fire affects our ability to generate genetic profiles suitable for forensic identification purposes.

Identification of Single-Nucleotide Polymorphisms in the Mitochondrial Genome and Kelch 13 Gene of Plasmodium falciparum in Different Geographical Populations.

The emergence of artemisinin-resistant Plasmodium falciparum parasites in Southeast Asia threatens malaria control and elimination. The interconnectedness of parasite populations may be essential to monitor the spread of resistance. Combining a published barcoding system of geographically restricted single-nucleotide polymorphisms (SNPs), mainly mitochondria of P. falciparum with SNPs in the K13 artemisinin resistance marker, could elucidate the parasite population structure and provide insight regarding the spread of drug resistance. We explored the diversity of mitochondrial SNPs (bp position 611-2825) and identified K13 SNPs from malaria patients in the districts of India (Ranchi), Tanzania (Korogwe), and Senegal (Podor, Richard Toll, Kaolack, and Ndoffane). DNA was amplified using a nested PCR and Sanger-sequenced. Overall, 199 K13 sequences (India: N = 92; Tanzania: N = 48; Senegal: N = 59) and 237 mitochondrial sequences (India: N = 93; Tanzania: N = 48; Senegal: N = 96) were generated. SNPs were identified by comparisons with reference genomes. We detected previously reported geographically restricted mitochondrial SNPs (T2175C and G1367A) as markers for parasites originating from the Indian subcontinent and several geographically unrestricted mitochondrial SNPs. Combining haplotypes with published P. falciparum mitochondrial genome data suggested possible regional differences within India. All three countries had G1692A, but Tanzanian and Senegalese SNPs were well-differentiated. Some mitochondrial SNPs are reported here for the first time. Four nonsynonymous K13 SNPs were detected: K189T (India, Tanzania, Senegal); A175T (Tanzania); and A174V and R255K (Senegal). This study supports the use of mitochondrial SNPs to determine the origin of the parasite and suggests that the P. falciparum populations studied were susceptible to artemisinin during sampling because all K13 SNPs observed were outside the propeller domain for artemisinin resistance.

Middle Jurassic origin in India: a new look at evolution of Vermileonidae and time-scaled relationships of lower brachyceran flies

AbstractVermileonidae (wormlions) comprises 61 described species in 12 genera and is one of the oddest and most rarely collected dipteran families. Larvae of Vermileonidae are famous for their pitfall prey behaviour, whereas the adults are rarely seen. Here we report, for the first time, the complete mitochondrial genome from members of Vermileonidae. Phylogenetic reconstruction based on a representative sampling of the order reveals new insights into relationships between the Vermileonidae and other members of lower brachyceran flies. A sister-group relationship between Vermileonidae and Xylophagidae is supported, and the higher-level clade relationships are Tabanomorpha + (Muscomorpha + (Xylophagomorpha + Stratiomyomorpha)). Combining mitochondrial genome data with a morphological phylogeny, geographical distribution and geological history, we propose that the Vermileonidae originated in India during the Middle Jurassic, spreading to Africa via land bridges during the Late Jurassic, to the Palaearctic after the collision of India with Laurasia in the Late Oligocene, and to the Nearctic in the Early Miocene, via either North Atlantic or Beringian land bridges. Wet forested regions have proved to be barriers to their dispersal, explaining their absence from Central Africa, South America and eastern North America.

The Evolutionary Patterns of Genome Size in Ensifera (Insecta: Orthoptera).

Genomic size variation has long been a focus for biologists. However, due to the lack of genome size data, the mechanisms behind this variation and the biological significance of insect genome size are rarely studied systematically. The detailed taxonomy and phylogeny of the Ensifera, as well as the extensive documentation concerning their morphological, ecological, behavioral, and distributional characteristics, make them a strong model for studying the important scientific problem of genome size variation. However, data on the genome size of Ensifera are rather sparse. In our study, we used flow cytometry to determine the genome size of 32 species of Ensifera, the smallest one being only 1C = 0.952 pg with the largest species up to 1C = 19.135 pg, representing a 20-fold range. This provides a broader blueprint for the genome size variation of Orthoptera than was previously available. We also completed the assembly of nine mitochondrial genomes and combined mitochondrial genome data from public databases to construct phylogenetic trees containing 32 species of Ensifera and three outgroups. Based on these inferred phylogenetic trees, we detected the phylogenetic signal of genome size variation in Ensifera and found that it was strong in both males and females. Phylogenetic comparative analyses revealed that there were no correlations between genome size and body size or flight ability in Tettigoniidae. Reconstruction of ancestral genome size revealed that the genome size of Ensifera evolved in a complex pattern, in which the genome size of the grylloid clade tended to decrease while that of the non-grylloid clade expanded significantly albeit with fluctuations. However, the evolutionary mechanisms underlying variation of genome size in Ensifera are still unknown.

How a Paleogenomic Approach Can Provide Details on Bioarchaeological Reconstruction: A Case Study from the Globular Amphorae Culture.

Ancient human remains have the potential to explain a great deal about the prehistory of humankind. Due to recent technological and bioinformatics advances, their study, at the palaeogenomic level, can provide important information about population dynamics, culture changes, and the lifestyles of our ancestors. In this study, mitochondrial and nuclear genome data obtained from human bone remains associated with the Neolithic Globular Amphorae culture, which were recovered in the Megalithic barrow of Kierzkowo (Poland), were reanalysed to gain insight into the social organisation and use of the archaeological site and to provide information at the individual level. We were able to successfully estimate the minimum number of individuals, sex, kin relationships, and phenotypic traits of the buried individuals, despite the low level of preservation of the bone samples and the intricate taphonomic conditions. In addition, the evaluation of damage patterns allowed us to highlight the presence of “intruders”—that is, of more recent skeletal remains that did not belong to the original burial. Due to its characteristics, the study of the Kierzkowo barrow represented a challenge for the reconstruction of the biological profile of the human community who exploited it and an excellent example of the contribution that ancient genomic analysis can provide to archaeological reconstruction.

Filling the gaps: The mitogenomes of Afrotropical egg-guarding frogs based on historical type material and a re-assessment of the nomenclatural status of Alexteroon Perret, 1988 (Hyperoliidae)

The African reedfrog taxon Alexteroon consists of only three described species with rather restricted geographical ranges. Although the assignment to a distinct genus is supported by multiple evidence, its position within the larger African hyperoliid radiation has been disputed. Available molecular data are scarce and the geographic records are few and scattered. The partially formalin fixed type series were previously not accessible to molecular analyses. This changed only very recently with the advancement of Next Generation Sequencing and ancient DNA techniques. Here we provide a reassessment of the current distribution and identity of all known species in this taxon based on (a) historical and new records, (b) morphological reanalyses of the type material and newly collected specimens from Angola and Gabon, and (c) newly established, nearly complete mitochondrial genome data from historical type and modern non-type material. We also present a molecular phylogeny (five mitochondrial loci 12S, 16S, ND1, ND2, COI, Cytb) for 78 sequences from 75 different species of Hyperolius retrieved from GenBank and 14 newly established Alexteroon sequences. We demonstrate that Alexteroon is more widely distributed than previously thought with records from northern Angola representing major southern range extensions. Results of the quantitative morphometric analyses show that the group has a rather conserved general body plan. Therefore qualitative phenotypic features observable in live specimens appear to be more useful for ad hoc species delimitation. We found Alexteroon to be nested within Hyperolius, corroborating previous findings. However, the combination of molecular data and consistent differences observed in morphology and ecology provide strong support for the distinctiveness of this evolutionary lineage within Hyperolius sensu lato. We therefore treat Alexteroon as a subgenus of Hyperolius and argue that the large and diverse genus Hyperolius is in need of revision that may result in new generic arrangements.

Molecular phylogeny of the grasshopper family Pyrgomorphidae (Caelifera, Orthoptera) reveals rampant paraphyly and convergence of traditionally used taxonomic characters

The grasshopper family Pyrgomorphidae is one of the most colorful orthopteran lineages, and includes biologically fascinating and culturally important species. Recent attempts to reconstruct the phylogeny of this family have resulted in a large degree of conflicts between a morphology-based study and a molecular-based study, mainly due to convergent morphological traits that affected phylogenetic reconstruction. In this study, a molecular phylogeny of Pyrgomorphidae based on 32 ingroup species and mitochondrial genome data is proposed, which is used to test the monophyly of the taxonomic groupings used in the current classification scheme. Using the ancestral character state reconstruction analyses and character mapping, we demonstrate that some of the morphological characters, including the male genitalia, which were considered to be taxonomically important, have evolved convergently across the phylogeny. We discuss the discrepancies between our phylogeny and the previous studies and propose an approach to establish a natural classification scheme for Pyrgomorphidae.

First next-generation sequencing data for Haploporidae (Digenea: Haploporata): characterization of complete mitochondrial genome and ribosomal operon for Parasaccocoelium mugili Zhukov, 1971.

The first data on a whole mitochondrial genome of Haploporidae, Parasaccocoelium mugili (Digenea: Haploporata: Haploporidae) was generated using the next-generation sequencing (NGS) approach. We sequenced the complete mitochondrial DNA (mtDNA) and ribosomal operon of Parasaccocoelium mugili, intestine parasite of mullet fish. The mtDNA of P. mugili contained 14,021 bp, including 12 protein-coding genes, two ribosomal genes, 22 tRNA genes, and non-coding region. The ribosomal operon of P. mugili was 8308 bp in length, including 18S rRNA gene (1981 bp), ITS1 rDNA (955 bp), 5.8S rRNA gene (157 bp), ITS2 rDNA (268 bp), 28S rRNA gene (4180 bp), and ETS (767 bp). We used the mtDNA protein-coding regions to make phylogenetic reconstructions of Haploporidae. Additionally, we performed the sequence cluster analysis based on codon usage bias of most of currently available mitochondrial genome data for trematodes. The observed gene arrangement in mtDNA sequence of P. mugili is identical to those of Plagiorchis maculosus (Rudolphi, 1802). Results of maximum likelihood (ML) phylogenetic analysis showed that P. mugili was closely related to Paragonimus species from the suborder Xiphidiata. The results of sequence cluster analysis based on codon usage bias showed that P. mugili has the highest similarity with Plagiorchis maculosus (Xiphidiata). Our results do not contradict to proposing a new suborder for Haploporoidea-Haploporata. On the basis of obtained results, the relationship between mitochondrial protein-coding gene rearrangements and synonymous nucleotide substitutions in mitochondrial genomes has been suggested.

Complete mitochondrial DNA sequence of the Psammocora profundacella (Scleractinia, Psammocoridae): mitogenome characterisation and phylogenetic implications

Complete mitochondrial DNA sequence data have played a significant role in phylogenetic and evolutionary studies of scleractinian corals. In this study, the complete mitogenome of Psammocora profundacella Gardiner, 1898, collected from Guangdong Province, China, was sequenced by next-generation sequencing for the first time. Psammocora profundacella is the first species for which a mitogenome has been sequenced in the family Psammocoridae. The length of its assembled mitogenome sequence was 16,274 bp, including 13 protein-coding genes, two tRNAs and two rRNAs. Its gene content and gene order were consistent with the other Scleractinia species. All genes were encoded on the H strand and the GC content of the mitochondrial genome was 30.49%. Gene content and order were consistent with the other Scleractinia species. Based on 13 protein-coding genes, Maximum Likelihood phylogenetic analysis showed that P. profundacella belongs to the “Robust” clade. Mitochondrial genome data provide important molecular information for understanding the phylogeny of stony corals. More variable markers and additional species should be sequenced to confirm the evolutionary relationships of Scleractinia in the future.

Characterization of whole mitochondrial genome Amyda cartilaginea from Dharmasraya, West Sumatera

Previous data of the whole mitochondrial genome of soft-shelled turtle that it’s available in a public repository: Dogania subplana, Pelochelys cantorii, Chitra indica, Trionyx triunguis, Apalone spinifera, Rafetus swinhoei, and Pelodiscus sinensis. The first two species have natural distribution in Indonesia. Amyda cartilaginea is a species of soft-shelled turtle that is abundant in Indonesia. However, the whole mitochondrial genome data of A. cartilaginea is not available. This study aims to characterize the partial mitochondrial genome and analyze the phylogenetic position of A. cartilaginea. We reported almost complete mitochondrial genome of A. cartilaginea that caught from Batanghari river in Dharmasraya District, West Sumatera. The amplification of mitochondrial DNA fragments was performed using several primers designed following mitochondrial gene organization and sequence of D. subplana (Accession No AF366350). We sequenced half of the whole mitochondrial genome (7757 bp, 48%). The gene organization of the mitochondrial genome of A. cartilaginea was identic with D. subplana and P. cantorii. The phylogenetic tree analysis based on 16SrRNA revealed that the position of A. cartilaginea clustered with another soft-shelled turtle. Further study is needed to make a complete sequence of the mitochondrial genome of A. cartilaginea, with special focus on the control region to be applied to sustainable wild population management.

Traces of Late Bronze and Early Iron Age Mongolian Horse Mitochondrial Lineages in Modern Populations.

The Mongolian horse is one of the most ancient and relatively unmanaged horse breeds. The population history of the Mongolian horse remains poorly understood due to a lack of information on ancient and modern DNA. Here, we report nearly complete mitochondrial genome data obtained from five ancient Mongolian horse samples of the Khereksur and Deer Stone culture (late 2nd to 1st third of the 1st millennium BC) and one ancient horse specimen from the Xiongnu culture (1st century BC to 1st century AD) using target enrichment and high-throughput sequencing methods. Phylogenetic analysis involving ancient, historical, and modern mitogenomes of horses from Mongolia and other regions showed the presence of three mitochondrial haplogroups in the ancient Mongolian horse populations studied here and similar haplotype composition of ancient and modern horse populations of Mongolia. Our results revealed genetic continuity between the Mongolian horse populations of the Khereksur and Deer Stone culture and those of the Xiongnu culture owing to the presence of related mitotypes. Besides, we report close phylogenetic relationships between haplotypes of the Khereksur and Deer Stone horses and the horses of indigenous breeds of the Middle East (Caspian and Iranian), China (Naqu, Yunnan, and Jinjiang), and Italy (Giara) as well as genetic similarity between the Xiongnu Mongolian horses and those of the most ancient breeds of the Middle East (Arabian) and Central Asia (Akhal-Teke). Despite all the migrations of the Mongolian peoples over the past 3000 years, mitochondrial haplogroup composition of Mongolian horse populations remains almost unchanged.

EZmito: a simple and fast tool for multiple mitogenome analyses

Complete mitochondrial genome data are frequently applied to address phylogenetic/phylogeographic issues at different taxonomic levels in ecology and evolution. While sample preparation/sequencing is becoming more and more straightforward thanks to dropping costs for next-generation sequencing (NGS), data preparation and visualization remains a manually intensive step that may lead to errors if improperly conducted. We have elaborated, and here introduce, EZmito, a simple and intuitive, freely accessible Web Server aimed at automating some of these tasks. EZmito is divided into three main tools: EZpipe that assembles DNA matrices for phylo-mitogenomic analyses; EZskew that calculates genome, strand, and codon nucleotide compositional skews and EZcodon which computes Relative Synonymous Codon Usage statistics as well as amino acid usage frequency over multiple mitogenomes. Output is produced in tabular format as well as publication-quality graphics.

Mitochondrial genes from 18 angiosperms fill sampling gaps for phylogenomic inferences of the early diversification of flowering plants

AbstractThe early diversification of angiosperms is thought to have been a rapid process, which may complicate phylogenetic analyses of early angiosperm relationships. Plastid and nuclear phylogenomic studies have raised several conflicting hypotheses regarding overall angiosperm phylogeny, but mitochondrial genomes have been largely ignored as a relevant source of information. Here we sequenced mitochondrial genomes from 18 angiosperms to fill taxon‐sampling gaps in Austrobaileyales, magnoliids, Chloranthales, Ceratophyllales, and major lineages of eudicots and monocots. We assembled a data matrix of 38 mitochondrial genes from 107 taxa to assess how well mitochondrial genomic data address current uncertainties in angiosperm relationships. Although we recovered conflicting phylogenies based on different data sets and analytical methods, we also observed congruence regarding deep relationships of several major angiosperm lineages: Chloranthales were always inferred to be the sister group of Ceratophyllales, Austrobaileyales to mesangiosperms, and the unplaced Dilleniales was consistently resolved as the sister to superasterids. Substitutional saturation, GC compositional heterogeneity, and codon‐usage bias are possible reasons for the noise/conflict that may impact phylogenetic reconstruction; and angiosperm mitochondrial genes may not be substantially affected by these factors. The third codon positions of the mitochondrial genes appear to contain more parsimony‐informative sites than the first and second codon positions, and therefore produced better resolved phylogenetic relationships with generally strong support. The relationships among these major lineages remain incompletely resolved, perhaps as a result of the rapidity of early radiations. Nevertheless, data from mitochondrial genomes provide additional evidence and alternative hypotheses for exploring the early evolution and diversification of the angiosperms.

Inferring the Phylogenetic Positions of Two Fig Wasp Subfamilies of Epichrysomallinae and Sycophaginae Using Transcriptomes and Mitochondrial Data.

Fig wasps are a group of insects (Hymenoptera: Chalcidoidea) that live in the compact syconia of fig trees (Moraceae: Ficus). Accurate classification and phylogenetic results are very important for studies of fig wasps, but the taxonomic statuses of some fig wasps, especially the non-pollinating subfamilies are difficult to determine, such as Epichrysomallinae and Sycophaginae. To resolve the taxonomic statuses of Epichrysomallinae and Sycophaginae, we obtained transcriptomes and mitochondrial genome (mitogenome) data for four species of fig wasps. These newly added data were combined with the data of 13 wasps (data on 11 fig wasp species were from our laboratory and two wasp species were download from NCBI). Based on the transcriptome and genome data, we obtained 145 single-copy orthologous (SCO) genes in 17 wasp species, and based on mitogenome data, we obtained 13 mitochondrial protein-coding genes (PCGs) for each of the 17 wasp species. Ultimately, we used 145 SCO genes, 13 mitochondrial PCGs and combined SCO genes and mitochondrial genes data to reconstruct the phylogenies of fig wasps using both maximum likelihood (ML) and Bayesian inference (BI) analyses. Our results suggest that both Epichrysomallinae and Sycophaginae are more closely related to Agaonidae with a high statistical support.