Integration of morphological and molecular data sets in estimating fungal phytogenies

1995 ◽  
Vol 73 (S1) ◽  
pp. 649-659 ◽  
Author(s):  
François Lutzoni ◽  
Rytas Vilgalys

To provide a clearer picture of fungal species relationships, increased efforts are being made to include both molecular and morphological data sets in phylogenetic studies. This general practice in systematics has raised many unresolved questions and controversies regarding how to best integrate the phylogenetic information revealed by morphological and molecular characters. This is because phylogenetic trees derived using different data sets are rarely identical. Such discrepancies can be due to sampling error, to the use of an inappropriate evolutionary model for a given data set, or to different phylogenetic histories between the organisms and the molecule. Methods have been developed recently to test for heterogeneity among data sets, although none of these methods have been subjected to simulation studies. In this paper we compare three tests: a protocol described by Rodrigo et al., an adapted version of Faith's T-PTP test, and Kishino and Hasegawa's likelihood test. These tests were empirically compared using seven lichenized and nonlichenized Omphalina species and the related species Arrhenia lobata (Basidiomycota, Agaricales) for which nrDNA large subunit sequences and morphological data were gathered. The results of these three tests were inconsistent, Rodrigo's test being the only one suggesting that the two data sets could be combined. One of the three most parsimonious trees obtained from the combined data set with eight species is totally congruent with the relationships among the same eight species in an analysis restricted to the same portion of the nrDNA large subunit but extended to 26 species of Omphalina and related genera. Therefore, the results from phylogenetic analyses of this large molecular data set converged on one of the three most parsimonious topologies generated by the combined data set analysis. This topology was not recovered from either data set when analysed separately. This suggests that Rodrigo's homogeneity test might be better suited than the two other tests for determining if trees obtained from different data sets are sampling statistics of the same phylogenetic history. Key words: data sets heterogeneity, homogeneity test, lichen phylogeny, Omphalina, ribosomal DNA.

Zootaxa ◽  
2004 ◽  
Vol 680 (1) ◽  
pp. 1 ◽  
Author(s):  
ARNE NYGREN

Autolytinae is revised based on available types, and newly collected specimens. Out of 170 nominal species, 18 are considered as incertae sedis, 43 are regarded as junior synonyms, and 25 are referred to as nomina dubia. The relationships of Autolytinae is assessed from 51 morphological characters and 211 states for 76 ingroup-taxa, and 460 molecular characters from mitochondrial 16S rDNA and nuclear 18S rDNA for 31 ingroup-taxa; outgroups include 12 non-autolytine syllid polychaetes. Two analyses are provided, one including morphological data only, and one with combined morphological and molecular data sets. The resulting strict consensus tree from the combined data is chosen for a reclassification. Three main clades are identified: Procerini trib. n., Autolytini Grube, 1850, and Epigamia gen. n. Proceraea Ehlers, 1864 and Myrianida Milne Edwards, 1845 are referred to as nomen protectum, while Scolopendra Slabber, 1781, Podonereis Blainville, 1818, Amytis Savigny, 1822, Polynice Savigny, 1822, and Nereisyllis Blainville, 1828 are considered


2015 ◽  
Vol 46 (3) ◽  
pp. 269-290 ◽  
Author(s):  
Ian J. Kitching ◽  
C. Lorna Culverwell ◽  
Ralph E. Harbach

Lutzia Theobald was reduced to a subgenus of Culex in 1932 and was treated as such until it was restored to its original generic status in 2003, based mainly on modifications of the larvae for predation. Previous phylogenetic studies based on morphological and molecular data have provided conflicting support for the generic status of Lutzia: analyses of morphological data support the generic status whereas analyses based on DNA sequences do not. Our previous phylogenetic analyses of Culicini (based on 169 morphological characters and 86 species representing the four genera and 26 subgenera of Culicini, most informal group taxa of subgenus Culex and five outgroup species from other tribes) seemed to indicate a conflict between adult and larval morphological data. Hence, we conducted a series of comparative and data exclusion analyses to determine whether the alternative positions of Lutzia are due to conflicting signal or to a lack of strong signal. We found that separate and combined analyses of adult and larval data support different patterns of relationships between Lutzia and other Culicini. However, the majority of conflicting clades are poorly supported and once these are removed from consideration, most of the topological disparity disappears, along with much of the resolution, suggesting that morphology alone does not have sufficiently strong signal to resolve the position of Lutzia. We critically examine the results of other phylogenetic studies of culicinine relationships and conclude that no morphological or molecular data set analysed in any study conducted to date has adequate signal to place Lutzia unequivocally with regard to other taxa in Culicini. Phylogenetic relationships observed thus far suggest that Lutzia is placed within Culex but further data and extended taxon sampling are required to confirm its position relative to Culex.


2010 ◽  
Vol 41 (3) ◽  
pp. 231-274 ◽  
Author(s):  
Jinzhong Fu ◽  
Owen Lonsdale ◽  
Brian Wiegmann ◽  
Stephen Marshall

AbstractIn this paper, the Clusiidae (Diptera: Schizophora) is analyzed phylogenetically using morphological and molecular data sets, and then redefined on the basis of derived morphological characters. The biology and distribution of the Clusiidae are also reviewed, a key is provided to the World genera, the status of the genus Craspedochaeta Czerny is reevaluated and the type of Heterochroa pictipennis Wulp is discussed. Molecular data sets include genomic DNA sequences from the mitochondrial genes COI (cytochrome oxidase subunit I) and COII (cytochrome oxidase subunit II), the large ribosomal nuclear subunit 28S, and the nuclear protein-coding carbomoylphosphate synthase (CPS) domain of CAD (or “rudimentary”). Genes were analyzed separately, in combination with each other, and in combination with a morphological data set. Although individual molecular data sets often provided conflicting phylogenetic signals, the topologies of the cladograms produced from each data set alone or in combination were largely similar. Most genus-level relationships and several basal divergences were unresolved, but Apiochaeta was very strongly and consistently supported as Sobarocephalinae, not Clusiinae. The Clusiinae and Sobarocephalinae are subsequently redefined using an adjusted morphological tree — retaining Apiochaeta in the Sobarocephalinae — that is only slightly longer (8.4%, or seven steps) than the most parsimonious tree. Our results illustrate the benefits of multiple independent data sets for phylogenetic reconstruction in order to verify and refine existing classifications.


2000 ◽  
Vol 31 (1) ◽  
pp. 71-90 ◽  
Author(s):  
Nils Møller Andersen ◽  
Jakob Damgaard ◽  
Felix A.H. Sperling

AbstractWe examined phylogenetic relationships among gerrid water striders of the genus Aquarius Schellenberg using molecular and morphological characters. The molecular data sets included 780 bp sequence data from the mitochondrial gene encoding cytochrome oxidase subunit I (COI), and 515 bp sequence data from the nuclear gene encoding elongation factor I alpha (EF-1α). The morphological data set was a slightly modified version of a previously published data set. We included all 17 known species and one subspecies of Aquarius as well as five species from three related genera, Gigantometra gigas, Limnoporus esakii, L. rufoscutellatus, Gerris pingreensis, and G. lacustris. Unweighted parsimony analyses of the COI data set gave a single most parsimonious tree (MPT) with a topology quite similar to the morphological tree. Parsimony analyses of the EF-1α data set gave 3 MPT's and a strict consensus of these trees gave a tree with a slightly different topology. A combined analysis of the three data sets gave a single MPT with the same topology as for the morphological data set alone. The phylogeny of Aquarius presented here supports the monophyly of the A. najas, remigis, conformis and paludum species groups as well as previous hypotheses about their relationships. On the other hand, the inclusion of molecular data weakens the support for the monophyly of the genus Aquarius, and questions the specific status of the eastern North American A. nebularis (as separate from A. conformis) and members of the Nearctic A. remigis group. Finally, we discuss the implications of the reconstructed phylogeny in the biogeography and ecological phylogenetics of Aquarius.


1995 ◽  
Vol 73 (S1) ◽  
pp. 667-676 ◽  
Author(s):  
Anders Tehler

Two data sets, one morphological and one molecular, for ascolocular fungi have been analysed separately for taxonomic congruence and in combination for total evidence. Data were analysed with cladistic parsimony, the total support test, and the congruence test. The morphological data set comprised 15 characters and four species, Arthonia radiata, Dendrographa leucophaea, Lecanactis abietina, and Schismatomma pericleum (Arthoniales). The molecular data include the same species and comprised sequence data with 21 informative sites from approximately half of the 18S ribosomal RNA gene. The morphological phylogeny is corroborated by the molecular phylogeny with regard to relationships of Arthonia radiata, Schismatomma pericleum, and Dendrographa leucophaea. But in the molecular phylogeny Lecanactis abietina is placed as a sister species to the former three species. In the phylogeny inferred from morphological data Lecanactis abietina and Dendrographa leucophaea constitute a sister pair with Schismatomma pericleum followed by Arthonia radiata as subsequent sister taxa. The consensus obtained from the taxonomic congruence method was fully collapsed and uninformative. The combined morphological and molecular data in total evidence produced one most parsimonious cladogram. In total evidence Lecanactis abietina is placed as sister species to Schismatomma pericleum and Dendrographa leucophaea all with Arthonia radiata as sister species. The most resolved and phylogenetically informative hypothesis was obtained from cladistic parsimony analysis using total evidence. A review of congruence between morphological and molecular data in determining gross relationships within the Eumycota and Ascomycetes is also given. Key words: Ascomycetes, Arthoniales, phylogeny, cladistics, taxonomic congruence, total evidence, 18SrDNA.


1995 ◽  
Vol 73 (1) ◽  
pp. 96-103 ◽  
Author(s):  
Zhi-Qiang Zhang

Two morphological data sets for eight trombidioid genera (Acari: Parasitengona) were analyzed separately and in combination using cladistic methods. One data set comprised 15 adult morphological characters, whereas the other comprised 29 larval morphological characters. Analyzed separately, the data on adults produced five equally parsimonious trees and the data on larvae produced three equally parsimonious trees. Analyses of both data sets revealed two distinct clades in Trombidiidae: clade A (Podothrombium, Pollicotrombium, Paratrombium, and Trombidium) and clade B (Dinothrombium, Clinotrombium, and Allothrombium). However, the within-clade generic relationships were resolved by data from larvae only in clade A and by data from adults only in clade B. Analysis of the combined data produced a single most parsimonious tree, with both clade A (Podothrombium (Pollicotrombium (Paratrombium, Trombidium))) and clade B (Dinothrombium (Clinotrombium, Allothrombium)) completely resolved. Thus, data on larvae and postlarvae are not only congruent but also complementary in revealing the phylogenetic relationships of these mites. The results support the principle of total evidence and the use of all available data for a single parsimony analysis.


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.


2008 ◽  
Vol 21 (3) ◽  
pp. 217 ◽  
Author(s):  
H. Thorsten Lumbsch ◽  
Armin Mangold ◽  
María P. Martín ◽  
John A. Elix

Species circumscriptions based on morphological data are difficult in crustose lichens with limited characters as they often show remarkable variability. An example is the genus Thelotrema s.str., a speciose genus of mostly tropical lichens. Morphological studies on Australian Thelotrema spp. were accompanied by a phylogenetic analysis of mt SSU rDNA sequence data of 19 species, including 25 newly obtained sequences. We performed maximum parsimony and Bayesian phylogenetic analyses of 50 samples, representing 25 species. Our results indicate that more species need to be accepted in Thelotrema than previously thought. Subtle morphological differences were found to be associated with independent lineages in the phylogenetic trees. Furthermore, monophyly of Thelotrema s.str. is strongly supported. On the basis of the corroboration of morphological evidence by molecular data, the new species Thelotrema capetribulense Mangold, T. crespoae Mangold, Lumbsch & Elix, T. oleosum Mangold, and T. pseudosubtile Mangold are described. The new combinations Chapsa phlyctidioides (Müll.Arg.) Mangold and Thelotrema defossum (Müll.Arg.) Mangold are proposed.


2021 ◽  
Author(s):  
Steffen Kiel

ABSTRACTPhylogenetic analyses using morphological data currently require hand-crafted character matrices, limiting the number of taxa that can be included. Here I explore how Deep Learning and Computer Vision approaches typically applied to image classification tasks, may be used to infer phylogenetic relationships among bivalves. A convolutional neural network (CNN) was trained on thousands of images showing species of 75 bivalve families. The predictions of the CNN on a large number of bivalve images are then interpreted as an indication of how similar these bivalves are to each other, are averaged by the families to which the species belonged, and visualized in a cluster diagram. In this cluster diagram, significantly more families clustered with members of their subclasses than expected by chance, confirming the feasibility of the approach. To address the issue of convergent evolution, two further CNNs were trained, on the same images but grouped by the orders and subclasses to which the species belonged. Combining predictions for the same images but on different taxonomic levels improved the inferred phylogenetic relationships also of families that the CNNs had not been trained on. Finally, this combined tree is merged with five published phylogenetic trees into a supertree, representing the largest single phylogeny of the Bivalvia to date, encompassing 128 families, including six exclusively fossil families and nine extant families for which presently no molecular data are available. Issues inherent to the approach and suggestions for future directions are discussed.


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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