Premise Speciation not associated with morphological shifts is challenging to detect unless molecular data are employed. Using Sanger-sequencing approaches, the Lomatium packardiae/L. anomalum subcomplex within the larger Lomatium triternatum complex could not be resolved. Therefore, we attempt to resolve these boundaries here. Methods The Angiosperms353 probe set was employed to resolve the ambiguity within Lomatium triternatum species complex using 48 accessions assigned to L. packardiae, L. anomalum, or L. triternatum. In addition to exon data, 54 nuclear introns were extracted and were complete for all samples. Three approaches were used to estimate evolutionary relationships and define species boundaries: STACEY, a Bayesian coalescent-based species tree analysis that takes incomplete lineage sorting into account; ASTRAL-III, another coalescent-based species tree analysis; and a concatenated approach using MrBayes. Climatic factors, morphological characters, and soil variables were measured and analyzed to provide additional support for recovered groups. Results The STACEY analysis recovered three major clades and seven subclades, all of which are geographically structured, and some correspond to previously named taxa. No other analysis had full agreement between recovered clades and other parameters. Climatic niche and leaflet width and length provide some predictive ability for the major clades. Conclusions The results suggest that these groups are in the process of incipient speciation and incomplete lineage sorting has been a major barrier to resolving boundaries within this lineage previously. These results are hypothesized through sequencing of multiple loci and analyzing data using coalescent-based processes.
Cytonuclear discordance, commonly detected in phylogenetic studies, is often attributed to hybridisation and/or incomplete lineage sorting (ILS). New sequencing technologies and analytical approaches can provide new insights into the relative importance of these processes. Hybridisation has previously been reported in the Australian endemic plant genus Adenanthos (Proteaceae). Like many Australian genera, Adenanthos is of relatively ancient origin, and provides an opportunity to examine long-term evolutionary consequences of gene flow between lineages. Using a hybrid capture approach, we assembled densely sampled low-copy nuclear and plastid DNA sequences for Adenanthos, inferred its evolutionary history, and used a Bayesian posterior predictive approach and coalescent simulations to assess relative contributions of hybridisation and ILS to cytonuclear discordance. Our analyses indicate that strong incongruence detected between our plastid and nuclear phylogenies is not only the result of ILS, but also result from extensive ancient introgression as well as recent chloroplast capture and introgression between extant Adenanthos species. The deep reticulation was also detected from long-persisting chloroplast haplotypes shared between evolutionarily distant species. These haplotypes may have persisted for over 12 Ma in localised populations across southwest Western Australia, indicating that the region is not only an important area for old endemic lineages and accumulation of species, but is also characterized by persistence of high genetic diversity. Deep introgression in Adenanthos coincided with the rapid radiation of the genus during the Miocene, a time when many Australian temperate plant groups radiated in response to large-scale climatic change. This study suggests that ancient introgression may play an important role in the evolution of the Australian flora more broadly.
Premise Comprising five families that vastly differ in species richness—ranging from Gelsemiaceae with 13 species to the Rubiaceae with 13,775 species—members of the Gentianales are often among the most species-rich and abundant plants in tropical forests. Despite considerable phylogenetic work within particular families and genera, several alternative topologies for family-level relationships within Gentianales have been presented in previous studies. Methods Here we present a phylogenomic analysis based on nuclear genes targeted by the Angiosperms353 probe set for approximately 150 species, representing all families and approximately 85% of the formally recognized tribes. We were able to retrieve partial plastomes from off-target reads for most taxa and infer phylogenetic trees for comparison with the nuclear-derived trees. Results We recovered high support for over 80% of all nodes. The plastid and nuclear data are largely in agreement, except for some weakly to moderately supported relationships. We discuss the implications of our results for the order’s classification, highlighting points of increased support for previously uncertain relationships. Rubiaceae is sister to a clade comprising (Gentianaceae + Gelsemiaceae) + (Apocynaceae + Loganiaceae). Conclusions The higher-level phylogenetic relationships within Gentianales are confidently resolved. In contrast to recent studies, our results support the division of Rubiaceae into two subfamilies: Cinchonoideae and Rubioideae. We do not formally recognize Coptosapelteae and Luculieae within any particular subfamily but treat them as incertae sedis. Our framework paves the way for further work on the phylogenetics, biogeography, morphological evolution, and macroecology of this important group of flowering plants.
Good understanding of the genes controlling root development is required to engineer root systems better adapted to different soil types. In wheat (Triticum aestivum L.), the 1RS.1BL wheat–rye (Secale cereale L.) translocation has been associated with improved drought tolerance and a large root system. However, an isogenic line carrying an interstitial segment from wheat chromosome arm 1BS in the distal region of the 1RS arm (1RSRW) showed reduced grain yield and shorter roots both in the field and in hydroponic cultures relative to isogenic lines with the complete 1RS arm. In this study, we used exome capture to characterize 1RSRW and its parental lines T-9 and 1B+40. We show that 1RSRW has a 7.0 Mb duplicated 1RS region and a 4.8 Mb 1BS insertion colinear with the 1RS duplication, resulting in triplicated genes. Lines homozygous for 1RSRW have short seminal roots, while lines heterozygous for this chromosome have roots of intermediate length. By contrast, near-isogenic lines carrying only the 1BS distal region or the 1RS-1BS duplication have long seminal roots similar to 1RS, suggesting a limited effect of the 1BS genes. These results suggest that the dosage of duplicated 1RS genes is critical for seminal root length. An induced deletion encompassing 38 orthologous wheat and rye duplicated genes restored root length and confirmed the importance of gene dosage in the short-root phenotype. We explored the expression profiles and functional annotation of these genes and discuss their potential as candidate genes for the regulation of seminal root length in wheat.
Premise Understanding relationships among orchid species and populations is of critical importance for orchid conservation. Target sequence capture has become a standard method for extracting hundreds of orthologous loci for phylogenomics. Up-front cost and time associated with design of bait sets makes this method prohibitively expensive for many researchers. Therefore, we designed a target capture kit to reliably sequence hundreds of orthologous loci across orchid lineages. Methods We designed an Orchidaceae target capture bait set for 963 single-copy genes identified in published orchid genome sequences. The bait set was tested on 28 orchid species, with representatives of the subfamilies Cypripedioideae, Orchidoideae, and Epidendroideae. Results Between 1,518,041 and 87,946,590 paired-end 150-base reads were generated for target-enriched genomic libraries. We assembled an average of 812 genes per library for Epidendroideae species and a mean of 501 genes for species in the subfamilies Orchidoideae and Cypripedioideae. Furthermore, libraries had on average 107 of the 254 genes that are included in the Angiosperms353 bait set, allowing for direct comparison of studies using either bait set. Discussion The Orchidaceae963 kit will enable greater accessibility and utility of next-generation sequencing for orchid systematics, population genetics, and identification in the illegal orchid trade.
Premise Researchers adopting target-enrichment approaches often struggle with the decision of whether to use universal or lineage-specific probe sets. To circumvent this quandary, we investigate the efficacy of a simultaneous enrichment by combining universal probes and lineage-specific probes in a single hybridization reaction, to benefit from the qualities of both probe sets with little added cost or effort. Methods and Results Using 26 Brassicaceae libraries and standard enrichment protocols, we compare results from three independent data sets. A large average fraction of reads mapping to the Angiosperms353 (24–31%) and Brassicaceae (35–59%) targets resulted in a sizable reconstruction of loci for each target set (x̄ ≥ 70%). Conclusions High levels of enrichment and locus reconstruction for the two target sets demonstrate that the sampling of genomic regions can be easily extended through the combination of probe sets in single enrichment reactions. We hope that these findings will facilitate the production of expanded data sets that answer individual research questions and simultaneously allow wider applications by the research community as a whole.
We used phylogenomic data and information from the beetle fossil record to reconstruct the phylogeny and historical biogeography of Australasian longhorn beetles (Cerambycidae) in the subfamily Lamiinae. We further focused our study on the distribution of proposed diagnostic morphological characters in Lamiinae, and on the phylogeny of Rhytiphora Audinet-Serville, Australia’s most species-rich genus of longhorn beetles. Lamiinae was monophyletic, but the majority of tribes were poly- or paraphyletic. Within Lamiinae, we recovered four main clades, including one clade mostly comprised of Australian endemic genera of probable Gondwanan origin. This clade also contained taxa that dispersed from Australia to New Zealand and experienced multiple independent instances of wing loss. Another of the four clades contained Australian genera that colonized the region from Asia, including Rhytiphora. The defining feature of Rhytiphora, the setose ‘sex patches’ on the male abdomen, was shared with many other Asian lamiine genera recovered in the same clade. Our results shed new light on the geographic and temporal origins of Australian Lamiinae, revealing an unexpected mixture of both ancient Gondwanan and recent Asian origins. Moreover, we confirmed rampant nonmonophyly at the tribal level among the Australasian genera of Lamiinae. Based on our results, we move 17 genera into Lamiinae incertae sedis and six genera into the tribe Ancitini Aurivillius. We also reinstate the tribe Niphonini Pascoe for part of the Asian-Australian Pteropliini Thomson and synonymize Achriotypa Pascoe with Rhytiphora.
The long-term impact of viruses residing in the human bone marrow (BM) remains unexplored. However, chronic inflammatory processes driven by single or multiple viruses could significantly alter hematopoiesis and immune function. We performed a systematic analysis of the DNAs of 38 viruses in the BM. We detected, by quantitative PCRs and next-generation sequencing, viral DNA in 88.9% of the samples, up to five viruses in one individual. Included were, among others, several herpesviruses, hepatitis B virus, Merkel cell polyomavirus and, unprecedentedly, human papillomavirus 31. Given the reactivation and/or oncogenic potential of these viruses, their repercussion on hematopoietic and malignant disorders calls for careful examination. Furthermore, the implications of persistent infections on the engraftment, regenerative capacity, and outcomes of bone marrow transplantation deserve in-depth evaluation.
Rove beetles of the tribe Quediini are abundant predators in humid microhabitats of forested, open, synanthropic or subterranean ecosystems, with just over 800 species distributed across the temperate and subtropical regions of the Northern Hemisphere. Previous molecular phylogenies included only a limited representation of this diversity but have already indicated that Quedius, containing the majority of Quediini species, is polyphyletic. Six genera, historically associated with Quediini but now Staphylininae incertae sedis, are known only from few pinned specimens and have never been sequenced. Recent synergy between target enrichment phylogenomics, low-input sequencing of dry, pinned insect specimens and advances in alpha taxonomic knowledge have made comprehensive sampling of Quediini tractable. Here we developed a novel probe set specialized for anchored hybrid enrichment of 1229 single-copy orthologous loci in Staphylinidae. In one of the largest target enrichment phylogenies of insects to-date, we sequenced 201 ingroup taxa to clearly delimit monophyletic Quediini within Staphylininae and resolve relationships within this tribe, with 46% of sampled taxa derived from pinned specimens (0–45 years old). Maximum likelihood and coalescent phylogenetic analyses produced well-resolved, congruent topologies that will serve as a framework for further exploration of this radiation and its necessary generic revision. The inclusion of nearly all remaining Staphylininae incertae sedis genera, all known only from pinned specimens, resulted in the creation of Quelaestrygonini Brunke, trib. n. and revised concepts for Cyrtoquediini and Indoquediini. Quediini was resolved as monophyletic with the transfer of Q. elevatus and Q. nigropolitus to other tribes but Quedius and its subgenera Microsaurus, Distichalius and Raphirus were shown to be para- or polyphyletic. Based on the results of our analyses, Velleiopsis Fairmaire, 1882 syn. n. and Megaquedius Casey, 1915 syn. n. are synonymized with Microsaurus Dejean, 1833 resulting in: Q. (Microsaurus) marginiventris (Fairmaire) comb. n., Q. (M.) varendorffi (Reitter) comb.n. Several species of Quedius were transferred from Microsaurus to Distichalius (Q. aethiops Smetana, Q. biann Smetana, Q. cingulatus Smetana and Q. taruni Smetana), Distichalius to Raphirus (Q. fagelianus Scheerpeltz) and Microsaurus to Raphirus (Q. mixtus Eppelsheim and Q. persicus Korge).
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