Papillomaviruses infect the skin and mucosal surfaces of diverse animal hosts with consequences ranging from asymptomatic colonization to highly malignant epithelial cancers. Increasing evidence suggests a role for papillomaviruses in the most common cutaneous malignancy of domestic cats, squamous cell carcinoma (SCC). Using total DNA sequencing we identified a novel feline papillomavirus in a nasal biopsy taken from a cat presenting with both nasal cavity lymphoma and recurrent squamous cell carcinoma affecting the nasal planum. We designate this novel virus as Felis catus papillomavirus 6 (FcaPV6). The complete FcaPV6 7453 bp genome was similar to those of other feline papillomaviruses and phylogenetic analysis revealed that it was most closely related to FcaPV3, although was distinct enough to represent a new viral type. Classification of FcaPV6 in a new genus alongside FcaPVs 3, 4 and 5 is supported. Archived excisional biopsy of the SCC, taken 20 months prior to presentation, was intensely positive on p16 immunostaining. FcaPV6, amplified using virus-specific, but not consensus, PCR, was the only papillomavirus detected in DNA extracted from the SCC. Conversely, renal lymphoma, sampled at necropsy two months after presentation, tested negative on FcaPV6-specific PCR. In sum, using metagenomics we demonstrate the presence of a novel feline papillomavirus in association with cutaneous squamous cell carcinoma.
Thanks to the development of high-throughput sequencing technologies, target enrichment sequencing of nuclear ultraconserved DNA elements (UCEs) now allows routine inference of phylogenetic relationships from thousands of genomic markers. Recently, it has been shown that mitochondrial DNA (mtDNA) is frequently sequenced alongside the targeted loci in such capture experiments. Despite its broad evolutionary interest, mtDNA is rarely assembled and used in conjunction with nuclear markers in capture-based studies. Here, we developed MitoFinder, a user-friendly bioinformatic pipeline, to efficiently assemble and annotate mitogenomic data from hundreds of UCE libraries. As a case study, we used ants (Formicidae) for which 501 UCE libraries have been sequenced whereas only 29 mitogenomes are available. We compared the efficiency of four different assemblers (IDBA-UD, MEGAHIT, MetaSPAdes, and Trinity) for assembling both UCE and mtDNA loci. Using MitoFinder, we show that metagenomic assemblers, in particular MetaSPAdes, are well suited to assemble both UCEs and mtDNA. Mitogenomic signal was successfully extracted from all 501 UCE libraries, allowing us to confirm species identification using CO1 barcoding. Moreover, our automated procedure retrieved 296 cases in which the mitochondrial genome was assembled in a single contig, thus increasing the number of available ant mitogenomes by an order of magnitude. By utilizing the power of metagenomic assemblers, MitoFinder provides an efficient tool to extract complementary mitogenomic data from UCE libraries, allowing testing for potential mitonuclear discordance. Our approach is potentially applicable to other sequence capture methods, transcriptomic data and whole genome shotgun sequencing in diverse taxa. The MitoFinder software is available from GitHub (https://github.com/RemiAllio/MitoFinder).
Premise Discordance between nuclear and organellar phylogenies (cytonuclear discordance) is a well-documented phenomenon at shallow evolutionary levels but has been poorly investigated at deep levels of plant phylogeny. Determining the extent of cytonuclear discordance across major plant lineages is essential not only for elucidating evolutionary processes, but also for evaluating the currently used framework of plant phylogeny, which is largely based on the plastid genome. Methods We present a phylogenomic examination of a major angiosperm clade (Asteridae) based on sequence data from the nuclear, plastid, and mitochondrial genomes as a means of evaluating currently accepted relationships inferred from the plastome and exploring potential sources of genomic conflict in this group. Results We recovered at least five instances of well-supported cytonuclear discordance concerning the placements of major asterid lineages (i.e., Ericales, Oncothecaceae, Aquifoliales, Cassinopsis, and Icacinaceae). We attribute this conflict to a combination of incomplete lineage sorting and hybridization, the latter supported in part by previously inferred whole-genome duplications. Conclusions Our results challenge several long-standing hypotheses of asterid relationships and have implications for morphological character evolution and for the importance of ancient whole-genome duplications in early asterid evolution. These findings also highlight the value of reevaluating broad-scale angiosperm and green-plant phylogeny with nuclear genomic data.
Abstract. Incongruence among phylogenetic results has become a common occurrence in analyses of genome-scale data sets. Incongruence originates from uncertainty
The members of the Temnothorax salvini (Forel) species group are rarely collected, arboreally nesting ants of Central American forests. Previously thought to consist of two broadly dispersed species, recent collections have revealed a diversity of specimens that defy the two-species salvini group concept, but these are difficult to distinguish from each other based solely on morphology. I contrast several model-based approaches to species delimitation based on target-enriched genomic data. With molecular data from thousands of ultraconserved elements (UCEs), mitochondrial genome sequences and morphometric data, I use an integrated approach to species delimitation within the salvini group. Morphometric data were analysed using cluster analysis of principal component analysis (PCA) output. I use several popular methods of molecular species delimitation, including bPTP, BPP and STACEY, using a novel approach to filtering UCE data based on posterior predictive checks of nucleotide substitution model adequacy. In addition, I use iBPP to integrate morphometric PCA data and filtered UCE data in a ‘total evidence’ analysis. I use geographical range data for an independent contrast to discriminate among competing species delimitation hypotheses. Furthermore, I investigate the evolutionary timescale and biogeographical history of the group and find that it arose roughly 13 Ma ago in habitats associated with present day mid-to-high elevations of the mountain complex spanning southern Mexico to northern Nicaragua. In addition, dispersal of the salvini group into the Southern Sierra Madre in Mexico, lowland habitats and the southern Central American cordilleras in Costa Rica and Panama subsequent to mountain building in southern Central America 5–8 Ma ago appears to follow a taxon-cycle dynamic, with the lowland-adapted T. aztecus representing the most recent expansion phase. I find that the salvini group, which previously contained two named species, is composed of nine, all of which are morphologically diagnosable a posteriori.
Asteraceae account for 10% of all flowering plant species, and 35-40% of these are in five closely-related tribes that total over 10,000 species. These tribes include Anthemideae, Astereae, Calenduleae, Gnaphalieae, and Senecioneae, which form one of two enormous clades within Subfamily Asteroideae. We took a phylogenomics approach to resolve evolutionary relationships among these five tribes. We sampled the nuclear and plastid genomes via HybSeq target enrichment and genome skimming, and recovered 74 plastid genes and nearly 1000 nuclear loci, known as Conserved Orthologous Sequences. We tested for conflicting support in both datasets and used network analyses to assess patterns of reticulation to explain the early evolutionary history of this lineage which has experienced whole genome duplications and rapid radiations. We found both concordance and conflicting support in both datasets and documented four ancient hybridization events. Due to the timing of the early radiation of this five-tribe lineage, shortly before the Eocene-Oligocene extinction event (34 MYA), early lineages were likely lost, obscuring some details of their early evolutionary history. This article is protected by copyright. All rights reserved.
Rogadinae are a cosmopolitan, species-rich braconid wasp subfamily whose species are endoparasitoids that attack larvae of a number of lepidopteran families. Members of this subfamily are characterized by pupating within the mummified host larval skin. The subfamily contains six tribes whose relationships have only been partially clarified: Aleiodini, Betylobraconini, Clinocentrini, Rogadini, Stiropiini and Yeliconini. The limits and composition of the closely related subfamilies to the Rogadinae, Hormiinae and Lysiterminae, also remain unclear. Here, we generated ultraconserved element data to reconstruct an almost fully resolved phylogeny for the members of Rogadinae and related subfamilies. Based on our best estimate of phylogeny, we confirm the monophyly of Rogadinae including Betylobraconini, synonymize Xenolobus Fahringer and Bequartia Cameron within the species-rich genus Aleiodes Wesmael (syn.n.) based on DNA, and synonymize Promesocentrus van Achterberg with Pilichremylus Belokobylskij (syn.n.) based on morphology. We also consistently recovered Hormiinae and Lysiterminae as not reciprocally monophyletic, and thus propose to unite their members under Hormiinae. The ancestral host preference for Rogadinae was probably attacking concealed lepidopteran larvae, with the occurrence of at least two main subsequent transitions to attack both concealed and exposed hosts, one within Rogadini and a second within Aleiodini. We highlight the importance of natural history collections as a source for conducting genomic-based studies using techniques that allow to obtain a substantial amount of data from considerably old preserved insect specimens.
Targeted capture of nuclear genes increasingly contributes to unravelling phylogenetic relationships that hitherto remained unresolved because of limitations of traditional Sanger sequencing. In particular, the study of tropical plant families has been compromised because they often rely on highly degraded DNA obtained from herbarium specimens. One such example is the pantropical Ochnaceae, which comprises 33 genera and approximately 550 species, occurring mostly in savannas and moist tropical forests. Here, we developed a set of baits covering about 660,000 bp from 275 nuclear genes used for the targeted enrichment based on all but one genus and more than 250 species. Using this novel dataset, we resolved the phylogenetic backbone of Ochnaceae, including that of Ochninae, and we established new relationships. Most importantly, our findings highlight that the neotropical and palaeotropical taxa of Sauvagesia form independent clades, requiring the re-erection of formerly separate genera. Ouratea and Ochna (both Ochninae), by far the most species-rich genera and represented by 120 and 41 species, respectively, came out as monophyletic. In contrast, the third-most species-rich genus, Campylospermum, is polyphyletic in two distinct clades. Ouratea, the only neotropical genus of Ochninae, was sister to the five palaeotropical genera of this subtribe. The bait kit developed in this study proved to be particularly useful for unravelling relationships within Ochninae, which includes about two-thirds of the species diversity in the family.
The gallopheasants comprise a clade of 22 species including some of the most elaborately plumaged and highly ornamented birds in the world. They also occupy a remarkable breath of environments and habitats, ranging from lowland rainforests to high grasslands and steppes of the Tibetan plateau. Here, we provide the first well-resolved species phylogeny of this charismatic group, inferred from ultraconserved elements, nuclear introns and mitochondrial DNA sequences. Unlike previous studies which found unresolvable relationships and suggested a rapid initial burst of diversification, we identified a well-resolved phylogeny supported in both concatenated and coalescent analytical frameworks, and a steady accrual of lineages through time. Morphological trait reconstructions demonstrated strong phylogenetic signal, not only for highly ornamented males, but also in more cryptically plumaged females. Environmental niche similarly exhibited strong phylogenetic signal. Moreover, evolution of male traits, female traits and environmental niche were all significantly correlated, making it difficult to disentangle their individual roles in gallopheasant diversification.
Human settlement of Madagascar traces back to the beginning of the first millennium with the arrival of Austronesians from Southeast Asia followed by migrations from Africa and Middle East. Remains of these different cultural, genetic and linguistic legacies are still present in Madagascar and other islands of the Indian Ocean. The close relationship between human migration and the introduction and spread of infectious diseases, a well-documented phenomenon, is particularly evident for the causative agent of leprosy, Mycobacterium leprae. In this study, we used whole-genome sequencing and molecular dating to characterize the genetic background and retrace the origin of the M. leprae strains circulating in Madagascar (n=30) and the Comoros (n=3), two islands where leprosy is still considered a public health problem and monitored as part of a drug resistance surveillance program. Most M. leprae strains (97%) from Madagascar and Comoros belonged to a new genotype as part of the branch 1, closely related to SNP-type 1D, named 1D-Malagasy. Other strains belonged to the genotype 1A (3%). We sequenced 39 strains from nine other countries, which together with previously published genomes amounted to 242 genomes that were used for molecular dating. Specific SNP markers for the new 1D-Malagasy genotype were used to screen samples from 11 countries and revealed this genotype to be restricted to Madagascar with the sole exception being a strain from Malawi. The overall analysis thus ruled out a possible introduction of leprosy by the Austronesian settlers, and suggests a later origin from East Africa, the Middle East or South Asia.
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