scholarly journals Compositional heterogeneity and outgroup choice influence the internal phylogeny of the ants

2017 ◽  
Author(s):  
Marek L. Borowiec ◽  
Christian Rabeling ◽  
Seán G. Brady ◽  
Brian L. Fisher ◽  
Ted R. Schultz ◽  
...  

AbstractKnowledge of the internal phylogeny and evolutionary history of ants (Formicidae), the world’s most species-rich clade of eusocial organisms, has dramatically improved since the advent of molecular phylogenetics. A number of relationships at the subfamily level, however, remain uncertain. Key unresolved issues include placement of the root of the ant tree of life and the relationships among the so-called poneroid subfamilies. Here we assemble a new data set to attempt a resolution of these two problems and carry out divergence dating, focusing on the age of the root node of crown Formicidae. For the phylogenetic analyses we included data from 110 ant species, including the key species Martialis heureka. We focused taxon sampling on non-formicoid lineages of ants to gain insight about deep nodes in the ant phylogeny. For divergence dating we retained a subset of 62 extant taxa and 42 fossils in order to approximate diversified sampling in the context of the fossilized birth-death process. We sequenced 11 nuclear gene fragments for a total of ~7.5 kb and investigated the DNA sequence data for the presence of among-taxon compositional heterogeneity, a property known to mislead phylogenetic inference, and for its potential to affect the rooting of the ant phylogeny. We found sequences of the Leptanillinae and several outgroup taxa to be rich in adenine and thymine (51% average AT content) compared to the remaining ants (45% average). To investigate whether this heterogeneity could bias phylogenetic inference we performed outgroup removal experiments, analysis of compositionally homogeneous sites, and a simulation study. We found that compositional heterogeneity indeed appears to affect the placement of the root of the ant tree but has limited impact on more recent nodes. We put forward a novel hypothesis regarding the rooting of the ant phylogeny, in which Martialis and the Leptanillinae together constitute a clade that is sister to all other ants. After correcting for compositional heterogeneity this emerges as the best-supported hypothesis of relationships at deep nodes in the ant tree. The results of our divergence dating under the fossilized birth-death process and diversified sampling suggest that the crown Formicidae originated during the Albian or Aptian ages of the Lower Cretaceous (103–124 Ma). In addition, we found support for monophyletic poneroids comprising the subfamilies Agroecomyrmecinae, Amblyoponinae, Apomyrminae, Paraponerinae, Ponerinae, and Proceratiinae, and well-supported relationships among these subfamilies except for the placement of Proceratiinae and (Amblyoponinae + Apomyrminae). Our phylogeny also highlights the non-monophyly of several ant genera, including Protanilla and Leptanilla in the Leptanillinae, Proceratium in the Proceratiinae, and Cryptopone, Euponera, and Mesoponera within the Ponerinae.

2021 ◽  
Author(s):  
Brendon E Boudinot ◽  
Marek L Borowiec ◽  
Matthew M Prebus

Within the Formicidae, the higher classification of nearly all subfamilies has been recently revised due to the findings of molecular phylogenetics. Here, we integrate morphology and molecular data to holistically address the evolution and classification of the ant genus Lasius, its tribe Lasiini, and their subfamily Formicinae. We accomplish this through a critical re-examination of morphology of extant and fossil taxa, molecular phylogenetic analyses, total-evidence dating under fossilized birth-death process, phylogeography, and ancestral state estimation. We use these results to provide revised taxonomic definitions for the Lasiini and select genera, and we provide a key to the genera of the Lasiini with emphasis on the Lasius genus group. We find that the crown Lasiini originated around the end of the Cretaceous on the Eurasian continent and is divisible into four morphologically distinct clades: Cladomyrma, the Lasius genus group, the Prenolepis genus group, and a previously undetected lineage we name XXXgen. n. The crown of the Lasius genus group is considerably younger than that of the Prenolepis genus group, indicating that extinction has played a major role in the evolution of the former clade. Lasius itself is divided into two well-supported monophyletic groups which are approximately equally speciose. We present evidence that temporary social parasitism and fungiculture arose in Lasius two times independently. Additionally, we recover the paraphyly of three Lasius subgenera and propose replacing all subgenera with an informal species group classification: Lasius = Acanthomyopssyn. rev., = Austrolasiussyn. n., = Cautolasiussyn. n., = Chthonolasius vsyn. n., = Dendrolasiussyn. n. Total-evidence analysis reveals that the Baltic-region amber fossil species Lasius pumilus and Pseudolasius boreus are misplaced to genus; we therefore designate XXXgen. n. for the former and XXXgen. n. for the latter. Further, we transfer XXX and Glaphyromyrmex out of the tribe, considering the former to be incertae sedis in the subfamily, and the latter a member of the Formicini (tribal transfer). Two final taxonomic actions are deemed necessary: synonymy of Lasius escamole Reza, 1925 with Liometopum apiculatum Mayr, 1870 syn. n. (subfamilial transfer), and transfer of Paratrechina kohli to Anoplolepis (tribal transfer, forming A. kohli (Forel, 1916) n. comb.).


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.


PLoS ONE ◽  
2021 ◽  
Vol 16 (9) ◽  
pp. e0257338
Author(s):  
Peggy L. Brady ◽  
Mark S. Springer

Pseudoextinction analyses, which simulate extinction in extant taxa, use molecular phylogenetics to assess the accuracy of morphological phylogenetics. Previous pseudoextinction analyses have shown a failure of morphological phylogenetics to place some individual placental orders in the correct superordinal clade. Recent work suggests that the inclusion of hypothetical ancestors of extant placental clades, estimated by ancestral state reconstructions of morphological characters, may increase the accuracy of morphological phylogenetic analyses. However, these studies reconstructed direct hypothetical ancestors for each extant taxon based on a well-corroborated molecular phylogeny, which is not possible for extinct taxa that lack molecular data. It remains to be determined if pseudoextinct taxa, and by proxy extinct taxa, can be accurately placed when their immediate hypothetical ancestors are unknown. To investigate this, we employed molecular scaffolds with the largest available morphological data set for placental mammals. Each placental order was sequentially treated as pseudoextinct by exempting it from the molecular scaffold and recoding soft morphological characters as missing for all its constituent species. For each pseudoextinct data set, we omitted the pseudoextinct taxon and performed a parsimony ancestral state reconstruction to obtain hypothetical predicted ancestors. Each pseudoextinct order was then evaluated in seven parsimony analyses that employed combinations of fossil taxa, hypothetical predicted ancestors, and a molecular scaffold. In treatments that included fossils, hypothetical predicted ancestors, and a molecular scaffold, only 8 of 19 pseudoextinct placental orders (42%) retained the same interordinal placement as on the molecular scaffold. In treatments that included hypothetical predicted ancestors but not fossils or a scaffold, only four placental orders (21%) were recovered in positions that are congruent with the scaffold. These results indicate that hypothetical predicted ancestors do not increase the accuracy of pseudoextinct taxon placement when the immediate hypothetical ancestor of the taxon is unknown. Hypothetical predicted ancestors are not a panacea for morphological phylogenetics.


PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e3055 ◽  
Author(s):  
Andrea Cau

Bayesian phylogenetic methods integrating simultaneously morphological and stratigraphic information have been applied increasingly among paleontologists. Most of these studies have used Bayesian methods as an alternative to the widely-used parsimony analysis, to infer macroevolutionary patterns and relationships among species-level or higher taxa. Among recently introduced Bayesian methodologies, the Fossilized Birth-Death (FBD) model allows incorporation of hypotheses on ancestor-descendant relationships in phylogenetic analyses including fossil taxa. Here, the FBD model is used to infer the relationships among an ingroup formed exclusively by fossil individuals, i.e., dipnoan tooth plates from four localities in the Ain el Guettar Formation of Tunisia. Previous analyses of this sample compared the results of phylogenetic analysis using parsimony with stratigraphic methods, inferred a high diversity (five or more genera) in the Ain el Guettar Formation, and interpreted it as an artifact inflated by depositional factors. In the analysis performed here, the uncertainty on the chronostratigraphic relationships among the specimens was included among the prior settings. The results of the analysis confirm the referral of most of the specimens to the taxaAsiatoceratodus,Equinoxiodus, LavocatodusandNeoceratodus, but reject those toCeratodusandFerganoceratodus. The resulting phylogeny constrained the evolution of the Tunisian sample exclusively in the Early Cretaceous, contrasting with the previous scenario inferred by the stratigraphically-calibrated topology resulting from parsimony analysis. The phylogenetic framework also suggests that (1) the sampled localities are laterally equivalent, (2) but three localities are restricted to the youngest part of the section; both results are in agreement with previous stratigraphic analyses of these localities. The FBD model of specimen-level units provides a novel tool for phylogenetic inference among fossils but also for independent tests of stratigraphic scenarios.


2021 ◽  
Vol 71 ◽  
pp. 747-763
Author(s):  
V. Deepak ◽  
Samuel Lalronunga ◽  
Esther Lalhmingliani ◽  
Abhijit Das ◽  
Surya Narayanan ◽  
...  

Xenodermidae is a generally poorly known lineage of caenophidian snakes found in South, East and Southeast Asia. We report molecular phylogenetic analyses for a multilocus data set comprising all five currently recognised genera and including new mitochondrial and nuclear gene sequence data for the recently described Stoliczkia vanhnuailianai. Our phylogenetic results provide very strong support for the non-monophyly of Stoliczkia, as presently constituted, with S. borneensis being more closely related to Xenodermus than to the Northeast Indian S. vanhnuailianai. Based on phylogenetic relationships and morphological distinctiveness, we transfer Stoliczkia borneensis to a new monotypic genus endemic to Borneo, Paraxenodermusgen. nov. We also present new morphological data for P. borneensis.


2021 ◽  
Author(s):  
Arong Luo ◽  
Chi Zhang ◽  
Qing-Song Zhou ◽  
Simon Y.W. Ho ◽  
Chao-Dong Zhu

Evolutionary timescales can be estimated using a combination of genetic data and fossil evidence based on the molecular clock. Bayesian phylogenetic methods such as tip dating and total-evidence dating provide a powerful framework for inferring evolutionary timescales, but the most widely used priors for tree topologies and node times often assume that present-day taxa have been sampled randomly or exhaustively. In practice, taxon sampling is often carried out so as to include representatives of major lineages, such as orders or families. We examined the impacts of these diversified sampling schemes on Bayesian molecular dating under the unresolved fossilized birth-death (FBD) process, in which fossil taxa are topologically constrained but their exact placements are not inferred. We used synthetic data generated by simulation of nucleotide sequence evolution, fossil occurrences, and diversified taxon sampling. Our analyses show that increasing sampling density does not substantially improve divergence-time estimates under benign conditions. However, when the tree topologies were fixed to those used for simulation or when evolutionary rates varied among lineages, the performance of Bayesian tip dating improves with sampling density. By exploring three situations of model mismatches, we find that including all relevant fossils without pruning off those inappropriate for the FBD process can lead to underestimation of divergence times. Our reanalysis of a eutherian mammal data set confirms some of the findings from our simulation study, and reveals the complexity of diversified taxon sampling in phylogenomic data sets. In highlighting the interplay of taxon-sampling density and other factors, the results of our study have useful implications for Bayesian molecular dating in the era of phylogenomics.


Genome ◽  
1999 ◽  
Vol 42 (5) ◽  
pp. 893-908 ◽  
Author(s):  
J Wu ◽  
K V Krutovskii ◽  
S H Strauss

We studied nuclear gene diversity and population differentiation using 91-98 randomly amplified polymorphic DNA (RAPD) loci in the California closed-cone pines knobcone (Pinus attenuata Lemm.), bishop (P. muricata D. Don), and Monterey (P. radiata D. Don) pines. A total of 384 trees from 13 populations were analyzed for RAPDs and another sample of 242 trees from 12 of these 13 populations were analyzed at 32-36 allozyme loci, using a published data set. Twenty-eight of 30 (93%) comigrating RAPD fragments tested were found to be homologous by Southern hybridization in all three species. Using an enriched mitochondrial DNA (mtDNA) preparation and a chloroplast DNA (cpDNA) library as probes, two fragments of cpDNA origin, and one of mtDNA origin present among RAPD profiles were excluded from analysis of nuclear gene diversity. RAPD markers revealed moderately higher intrapopulation gene diversity and substantially higher total genetic diversity and population differentiation than did allozyme markers for each species. We performed a simulation study using allozyme data, which showed that the dominant and biallelic nature of RAPD markers could explain the differences observed in differentiation parameters, but not in gene diversity; RAPD phenotypes appear to represent more underlying gene diversity than do allozyme phenotypes. Results of joint phylogenetic analyses of both the RAPD and allozyme markers strongly supported a common ancestor for P. radiata and P. attenuata pines, and south-to-north migration histories for all three species.Key words: allozymes, dominance, gene diversity, Pinus attenuata, Pinus muricata, Pinus radiata, phylogeny, RAPDs.


2021 ◽  
Author(s):  
Joelle Barido-Sottani ◽  
Dagmara Zyla ◽  
Tracy A. Heath

Bayesian total-evidence approaches under the fossilized birth-death model enable biologists to combine fossil and extant data---while accounting for uncertainty in the ages of fossil specimens---in an integrative phylogenetic analysis. Fossil age uncertainty is a key feature of the fossil record as many empirical datasets may contain a mix of precisely dated and poorly dated fossil specimens or deposits. In this study, we explore whether reliable age estimates for fossil specimens can be obtained from Bayesian total-evidence phylogenetic analyses under the fossilized birth-death model. Through simulations based on the example of the Baltic amber deposit, we show that estimates of fossil ages obtained through such an analysis are accurate, particularly when the proportion of poorly dated specimens remains low and the majority of fossil specimens have precise dates. We confirm our results using an empirical dataset of living and fossil penguins by artificially increasing the age uncertainty around some fossil specimens and showing that the resulting age estimates overlap with the recorded age ranges. Our results are applicable to many empirical datasets where classical methods of establishing fossil ages have failed, such as the Baltic amber and the Gobi Desert deposits.


1986 ◽  
Vol 23 (04) ◽  
pp. 1013-1018
Author(s):  
B. G. Quinn ◽  
H. L. MacGillivray

Sufficient conditions are presented for the limiting normality of sequences of discrete random variables possessing unimodal distributions. The conditions are applied to obtain normal approximations directly for the hypergeometric distribution and the stationary distribution of a special birth-death process.


Genetics ◽  
1997 ◽  
Vol 146 (3) ◽  
pp. 995-1010 ◽  
Author(s):  
Rafael Zardoya ◽  
Axel Meyer

The complete nucleotide sequence of the 16,407-bp mitochondrial genome of the coelacanth (Latimeria chalumnae) was determined. The coelacanth mitochondrial genome order is identical to the consensus vertebrate gene order which is also found in all ray-finned fishes, the lungfish, and most tetrapods. Base composition and codon usage also conform to typical vertebrate patterns. The entire mitochondrial genome was PCR-amplified with 24 sets of primers that are expected to amplify homologous regions in other related vertebrate species. Analyses of the control region of the coelacanth mitochondrial genome revealed the existence of four 22-bp tandem repeats close to its 3′ end. The phylogenetic analyses of a large data set combining genes coding for rRNAs, tRNA, and proteins (16,140 characters) confirmed the phylogenetic position of the coelacanth as a lobe-finned fish; it is more closely related to tetrapods than to ray-finned fishes. However, different phylogenetic methods applied to this largest available molecular data set were unable to resolve unambiguously the relationship of the coelacanth to the two other groups of extant lobe-finned fishes, the lungfishes and the tetrapods. Maximum parsimony favored a lungfish/coelacanth or a lungfish/tetrapod sistergroup relationship depending on which transversion:transition weighting is assumed. Neighbor-joining and maximum likelihood supported a lungfish/tetrapod sistergroup relationship.


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