scholarly journals Phylogenomics of the adaptive radiation of Triturus newts supports gradual ecological niche expansion towards an incrementally aquatic lifestyle

2018 ◽  
Author(s):  
B. Wielstra ◽  
E. McCartney-Melstad ◽  
J.W. Arntzen ◽  
R.K. Butlin ◽  
H.B. Shaffer

AbstractNewts of the genus Triturus (marbled and crested newts) exhibit substantial variation in the number of trunk vertebrae (NTV) and a higher NTV corresponds to a longer annual aquatic period. Because the Triturus phylogeny has thwarted resolution to date, the evolutionary history of NTV, annual aquatic period, and their potential coevolution has remained unclear. To resolve the phylogeny of Triturus, we generated a c. 6,000 transcriptome-derived marker data set using a custom target enrichment probe set, and conducted phylogenetic analyses using: 1) data concatenation with RAxML, 2) gene-tree summary with ASTRAL, and 3) species-tree estimation with SNAPP. All analyses produce the same, highly supported topology, despite cladogenesis having occurred over a short timeframe, resulting in short internal branch lengths. Our new phylogenetic hypothesis is consistent with the minimal number of inferred changes in NTV count necessary to explain the diversity in NTV observed today. Although a causal relationship between NTV, body form, and aquatic ecology has yet to be experimentally established, our phylogeny indicates that these features have evolved together, and suggest that they may underlie the adaptive radiation that characterizes Triturus.

PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e2307 ◽  
Author(s):  
Nicola S. Heckeberg ◽  
Dirk Erpenbeck ◽  
Gert Wörheide ◽  
Gertrud E. Rössner

Cervid phylogenetics has been puzzling researchers for over 150 years. In recent decades, molecular systematics has provided new input for both the support and revision of the previous results from comparative anatomy but has led to only partial consensus. Despite all of the efforts to reach taxon-wide species sampling over the last two decades, a number of cervid species still lack molecular data because they are difficult to access in the wild. By extracting ancient DNA from museum specimens, in this study, we obtained partial mitochondrial cytochrome b gene sequences forMazama bricenii,Mazama chunyi,Muntiacus atherodes,Pudu mephistophiles, andRusa marianna, including three holotypes. These new sequences were used to enrich the existing mitochondrial DNA alignments and yielded the most taxonomically complete data set for cervids to date. Phylogenetic analyses provide new insights into the evolutionary history of these five species. However, systematic uncertainties withinMuntiacuspersist and resolving phylogenetic relationships withinPuduandMazamaremain challenging.


2020 ◽  
Vol 36 (18) ◽  
pp. 4819-4821
Author(s):  
Anastasiia Kim ◽  
James H Degnan

Abstract Summary PRANC computes the Probabilities of RANked gene tree topologies under the multispecies coalescent. A ranked gene tree is a gene tree accounting for the temporal ordering of internal nodes. PRANC can also estimate the maximum likelihood (ML) species tree from a sample of ranked or unranked gene tree topologies. It estimates the ML tree with estimated branch lengths in coalescent units. Availability and implementation PRANC is written in C++ and freely available at github.com/anastasiiakim/PRANC. Supplementary information Supplementary data are available at Bioinformatics online.


2021 ◽  
Vol 12 ◽  
Author(s):  
Mi-Jeong Yoo ◽  
Byoung-Yoon Lee ◽  
Sangtae Kim ◽  
Chae Eun Lim

The genus Hosta (Agavoideae and Asparagaceae) is one of the most popular landscaping and ornamental plants native to temperate East Asia. Their popularity has led to extensive hybridization to develop various cultivars. However, their long history of hybridization, cultivation, and selection has brought about taxonomic confusion in the Hosta species delimitation along with their indistinguishable morphology. Here, we conducted the first broad phylogenetic analyses of Hosta species based on the most comprehensive genomic data set to date. To do so, we captured 246 nuclear gene sequences and plastomes from 55 accessions of Korean Hosta species using the Hyb-Seq method. As a result, this study provides the following novel and significant findings: (1) phylogenetic analyses of the captured sequences retrieved six species of Hosta in South Korea compared to five to eleven species based on the previous studies, (2) their phylogenetic relationships suggested that the large genome size was ancestral and the diversification of Korean Hosta species was accompanied by decreases in genome sizes, (3) comparison between nuclear genes and plastome revealed several introgressive hybridization events between Hosta species, and (4) divergence times estimated here showed that Hosta diverged 35.59 million years ago, while Korean Hosta species rapidly diversified during the late Miocene. Last, we explored whether these genomic data could be used to infer the origin of cultivars. In summary, this study provides the most comprehensive genomic resources to be used in phylogenetic, population, and conservation studies of Hosta, as well as for unraveling the origin of many cultivars.


Parasitology ◽  
2008 ◽  
Vol 136 (1) ◽  
pp. 55-65 ◽  
Author(s):  
L. B. VIOLA ◽  
R. S. ALMEIDA ◽  
R. C. FERREIRA ◽  
M. CAMPANER ◽  
C. S. A. TAKATA ◽  
...  

SUMMARYIn this study, using a combined data set of SSU rDNA and gGAPDH gene sequences, we provide phylogenetic evidence that supports clustering of crocodilian trypanosomes from the Brazilian Caiman yacare (Alligatoridae) and Trypanosoma grayi, a species that circulates between African crocodiles (Crocodilydae) and tsetse flies. In a survey of trypanosomes in Caiman yacare from the Brazilian Pantanal, the prevalence of trypanosome infection was 35% as determined by microhaematocrit and haemoculture, and 9 cultures were obtained. The morphology of trypomastigotes from caiman blood and tissue imprints was compared with those described for other crocodilian trypanosomes. Differences in morphology and growth behaviour of caiman trypanosomes were corroborated by molecular polymorphism that revealed 2 genotypes. Eight isolates were ascribed to genotype Cay01 and 1 to genotype Cay02. Phylogenetic inferences based on concatenated SSU rDNA and gGAPDH sequences showed that caiman isolates are closely related to T. grayi, constituting a well-supported monophyletic assemblage (clade T. grayi). Divergence time estimates based on clade composition, and biogeographical and geological events were used to discuss the relationships between the evolutionary histories of crocodilian trypanosomes and their hosts.


2018 ◽  
Vol 19 (3) ◽  
Author(s):  
Michel Barros Faria ◽  
Maria Clara Santos Ribeiro

Myotis is the largest genus of the Vespertilionidae family. It presents a cosmopolitan geographical distribution and is considered an example of adaptive radiation, however, with only nine species recorded for Brazil. This study synthesized aspects of the geographic distribution by map punctuating the main records for each species, karyotype, and phylogeny in contribution to the understanding of the taxonomic complex of the genus Myotis in Brazil. A search in bibliographic databases (e.g., Web of Science and SciElo) was carried out using keywords. The phylogeny study was based on the sequencing of a specimen of Myotis ruber collected in a fragment of the Altantic Forest of Minas Gerais; this specimen was deposited at the Newton Baião de Azevedo Museum of Zoology. The genus showed to be widely distributed in the Brazilian territory, with Myotis nigricans being the most widespread. In addition, high karyotypic conservatism was observed in all species of the genus. The phylogenetic analyses using the mt-Cytb gene corroborated the monophyletic aspect of the genus and the Myotis ruber species.


2006 ◽  
Vol 17 (3) ◽  
Author(s):  
Andreas Düring ◽  
Martina Brückner ◽  
Dietrich Mossakowski

Phylogenetic analyses of Chrysocarabus taxa using different markers result in different phylogenetic trees. In particular, the mitochondrial gene tree contradicts the results of morphological and inbreeding studies. Two very different haplotypes of Carabus splendens Olivier, 1790 do not form a clade within this phylogenetic tree. We have earlier proposed that contradictory results are due to introgression. To verify our hypothesis, we analysed the internal transcribed spacer 2. No substitutions were observed in these nuclear sequences between the individuals of Carabus splendens, which contain the different mitochondrial haplotypes in question. The differences in the gene trees based on mitochondrial and nuclear sequences can be explained with at least two introgression events.


2018 ◽  
Author(s):  
David A. Duchêne ◽  
K. Jun Tong ◽  
Charles S. P. Foster ◽  
Sebastián Duchêne ◽  
Robert Lanfear ◽  
...  

AbstractEvolution leaves heterogeneous patterns of nucleotide variation across the genome, with different loci subject to varying degrees of mutation, selection, and drift. Appropriately modelling this heterogeneity is important for reliable phylogenetic inference. One modelling approach in statistical phylogenetics is to apply independent models of molecular evolution to different groups of sites, where the groups are usually defined by locus, codon position, or combinations of the two. The potential impacts of partitioning data for the assignment of substitution models are well appreciated. Meanwhile, the treatment of branch lengths has received far less attention. In this study, we examined the effects of linking and unlinking branch-length parameters across loci. By analysing a range of empirical data sets, we find that the best-fitting model for phylogenetic inference is consistently one in which branch lengths are proportionally linked: gene trees have the same pattern of branch-length variation, but with varying absolute tree lengths. This model provided a substantially better fit than those that either assumed identical branch lengths across gene trees or that allowed each gene tree to have its own distinct set of branch lengths. Using simulations, we show that the fit of the three different models of branch lengths varies with the length of the sequence alignment and with the number of taxa in the data set. Our findings suggest that a model with proportionally linked branch lengths across loci is likely to provide the best fit under the conditions that are most commonly seen in practice. In future work, improvements in fit might be afforded by models with levels of complexity intermediate to proportional and free branch lengths. The results of our study have implications for model selection, computational efficiency, and experimental design in phylogenomics.


2020 ◽  
Author(s):  
Paul D. Blischak ◽  
Coleen E. Thompson ◽  
Emiko M. Waight ◽  
Laura S. Kubatko ◽  
Andrea D. Wolfe

AbstractReticulate evolutionary events are hallmarks of plant phylogeny, and are increasingly recognized as common occurrences in other branches of the Tree of Life. However, inferring the evolutionary history of admixed lineages presents a difficult challenge for systematists due to genealogical discordance caused by both incomplete lineage sorting (ILS) and hybridization. Methods that accommodate both of these processes are continuing to be developed, but they often do not scale well to larger numbers of species. An additional complicating factor for many plant species is the occurrence of whole genome duplication (WGD), which can have various outcomes on the genealogical history of haplotypes sampled from the genome. In this study, we sought to investigate patterns of hybridization and WGD in two subsections from the genus Penstemon (Plantaginaceae; subsect. Humiles and Proceri), a speciose group of angiosperms that has rapidly radiated across North America. Species in subsect. Humiles and Proceri occur primarily in the Pacific Northwest of the United States, occupying habitats such as mesic, subalpine meadows, as well as more well-drained substrates at varying elevations. Ploidy levels in the subsections range from diploid to hexaploid, and it is hypothesized that most of the polyploids are hybrids (i.e., allopolyploids). To estimate phylogeny in these groups, we first developed a method for estimating quartet concordance factors (QCFs) from multiple sequences sampled per lineage, allowing us to model all haplotypes from a polyploid. QCFs represent the proportion of gene trees that support a particular species quartet relationship, and are used for species network estimation in the program SNaQ (Solís-Lemus & Ané. 2016. PLoS Genet. 12:e1005896). Using phased haplotypes for nuclear amplicons, we inferred species trees and networks for 38 taxa from P. subsect. Humiles and Proceri. Our phylogenetic analyses recovered two clades comprising a mix of taxa from both subsections, indicating that the current taxonomy for these groups is inconsistent with our estimates of phylogeny. In addition, there was little support for hypotheses regarding the formation of putative allopolyploid lineages. Overall, we found evidence for the effects of both ILS and admixture on the evolutionary history of these species, but were able to evaluate our taxonomic hypotheses despite high levels of gene tree discordance. Our method for estimating QCFs from multiple haplotypes also allowed us to include species of varying ploidy levels in our analyses, which we anticipate will help to facilitate estimation of species networks in other plant groups as well.


2020 ◽  
Author(s):  
Liming Cai ◽  
Zhenxiang Xi ◽  
Emily Moriarty Lemmon ◽  
Alan R Lemmon ◽  
Austin Mast ◽  
...  

Abstract The genomic revolution offers renewed hope of resolving rapid radiations in the Tree of Life. The development of the multispecies coalescent (MSC) model and improved gene tree estimation methods can better accommodate gene tree heterogeneity caused by incomplete lineage sorting (ILS) and gene tree estimation error stemming from the short internal branches. However, the relative influence of these factors in species tree inference is not well understood. Using anchored hybrid enrichment, we generated a data set including 423 single-copy loci from 64 taxa representing 39 families to infer the species tree of the flowering plant order Malpighiales. This order includes nine of the top ten most unstable nodes in angiosperms, which have been hypothesized to arise from the rapid radiation during the Cretaceous. Here, we show that coalescent-based methods do not resolve the backbone of Malpighiales and concatenation methods yield inconsistent estimations, providing evidence that gene tree heterogeneity is high in this clade. Despite high levels of ILS and gene tree estimation error, our simulations demonstrate that these two factors alone are insufficient to explain the lack of resolution in this order. To explore this further, we examined triplet frequencies among empirical gene trees and discovered some of them deviated significantly from those attributed to ILS and estimation error, suggesting gene flow as an additional and previously unappreciated phenomenon promoting gene tree variation in Malpighiales. Finally, we applied a novel method to quantify the relative contribution of these three primary sources of gene tree heterogeneity and demonstrated that ILS, gene tree estimation error, and gene flow contributed to 10.0%, 34.8%, and 21.4% of the variation, respectively. Together, our results suggest that a perfect storm of factors likely influence this lack of resolution, and further indicate that recalcitrant phylogenetic relationships like the backbone of Malpighiales may be better represented as phylogenetic networks. Thus, reducing such groups solely to existing models that adhere strictly to bifurcating trees greatly oversimplifies reality, and obscures our ability to more clearly discern the process of evolution.


IMA Fungus ◽  
2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Takamichi Orihara ◽  
Rosanne Healy ◽  
Adriana Corrales ◽  
Matthew E. Smith

ABSTRACTAmong many convergently evolved sequestrate fungal genera in Boletaceae (Boletales, Basidiomycota), the genus Octaviania is the most diverse. We recently collected many specimens of Octaviania subg. Octaviania, including several undescribed taxa, from Japan and the Americas. Here we describe two new species in subgenus Octaviania, O. tenuipes and O. tomentosa, from temperate to subtropical evergreen Fagaceae forests in Japan based on morphological observation and robust multilocus phylogenetic analyses (nrDNA ITS and partial large subunit [LSU], translation elongation factor 1-α gene [TEF1] and the largest subunit of RNA polymerase II gene [RPB1]). Based on specimens from the Americas as well as studies of the holotype, we also taxonomically re-evaluate O. asterosperma var. potteri. Our analysis suggests that O. asterosperma var. potteri is a distinct taxon within the subgenus Octaviania so we recognize this as O. potteri stat. nov. We unexpectedly collected O. potteri specimens from geographically widespread sites in the USA, Japan and Colombia. This is the first verified report of Octaviania from the South American continent. Our molecular analyses also revealed that the RPB1 sequence of one O. tenuipes specimen was identical to that of a closely related species, O. japonimontana, and that one O. potteri specimen from Minnesota had an RPB1 sequence of an unknown species of O. subg. Octaviania. Additionally, one O. japonimontana specimen had an unusually divergent TEF1 sequence. Gene-tree comparison and phylogenetic network analysis of the multilocus dataset suggest that these heterogenous sequences are most likely the result of previous inter- and intra-specific hybridization. We hypothesize that frequent hybridization events in Octaviania may have promoted the high genetic and species diversity found within the genus.


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