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Mol Phylogenet Evol [journal]
- A confounding effect of missing data on character conflict in maximum likelihood and Bayesian MCMC phylogenetic analyses. [JOURNAL ARTICLE]
- Mol Phylogenet Evol 2014 Aug 27.
Contrived and simulated examples were used to quantify the range of conditions in which maximum likelihood and Bayesian MCMC methods are biased in favor of phylogenetic signal present in globally sampled characters over that present in conflicting locally sampled characters (those with missing data). The bias occurs in both the optimal tree identified as well as branch supports even when there are more locally sampled characters supporting the conflicting topology. The bias can lead to high bootstrap, SH-like aLRT support (up to 100%), and posterior probabilities for the conflicting clades. The bias can occur even when only a single terminal has missing data. The bias is not limited to likelihood methods that only ever present a single optimal tree that is fully resolved (as in PhyML and RAxML)-it can also occur in branch-and-bound PAUP∗ searches. The bias persists despite sampling numerous characters, and the bias is consistently unidirectional. The bias may occur in the context of incongruence between gene trees as well as within a single gene wherein terminals have different sequence lengths caused by DNA-amplification differences or gaps caused by indels. This bias is another example wherein commonly implemented parametric phylogenetic methods interpret ambiguity as support. In contrast, parsimony is robust to the bias.
- Global phylogeny and biogeography of grammitid ferns (Polypodiaceae). [JOURNAL ARTICLE]
- Mol Phylogenet Evol 2014 Aug 27.
We examined the global historical biogeography of grammitid ferns (Polypodiaceae) within a phylogenetic context. We inferred phylogenetic relationships of 190 species representing 31 of the 33 currently recognized genera of grammitid ferns by analyzing DNA sequence variation of five plastid DNA regions. We estimated the ages of cladogenetic events on an inferred phylogeny using secondary fossil calibration points. Historical biogeographical patterns were inferred via ancestral area reconstruction. Our results supported four large-scale phylogenetic and biogeographic patterns: 1) a monophyletic grammitid clade that arose among Neotropical polypod ancestors about 31.4 Ma; 2) a paraphyletic assemblage of clades distributed in the Neotropics and the Afro-Malagasy region; 3) a large clade distributed throughout the Asia-Malesia-Pacific region that originated about 23.4 Ma; and, 4) an Australian or New Zealand origin of the circumaustral genus Notogrammitis. Most genera were supported as monophyletic except for Grammitis, Oreogrammitis, Radiogrammitis, and Zygophlebia. Grammitid ferns are a well-supported monophyletic group with two biogeographically distinct lineages: a primarily Neotropical grade exhibiting several independent successful colonizations to the Afro-Malagasy region and a primarily Paleotropical clade exhibiting multiple independent dispersals to remote Pacific islands and temperate, austral regions.
- Global Comparison of Multiple-segmented Viruses in 12-dimensional Genome Space. [JOURNAL ARTICLE]
- Mol Phylogenet Evol 2014 Aug 26.
We have recently developed a computational approach in a vector space for genome-based virus classification. This approach, called the "Natural Vector (NV) representation", which is an alignment-free method, allows us to classify single-segmented viruses with high speed and accuracy. For multiple-segmented viruses, typically phylogenetic trees of each segment are reconstructed for discovering viral phylogeny. Consensus tree methods may be used to combine the phylogenetic trees based on different segments. However, consensus tree methods were not developed for instances where the viruses have different numbers of segments or where their segments do not match well. We propose a novel approach for comparing multiple-segmented viruses globally, even in cases where viruses contain different numbers of segments. Using our method, each virus is represented by a set of vectors in R(12). The Hausdorff distance is then used to compare different sets of vectors. Phylogenetic trees can be reconstructed based on this distance. The proposed method is used for predicting classification labels of viruses with n-segments (n ⩾ 1). The correctness rates of our predictions based on cross-validation are as high as 96.5%, 95.4%, 99.7%, and 95.6% for Baltimore class, family, subfamily, and genus, respectively, which are comparable to the rates for single-segmented viruses only. Our method is not affected by the number or order of segments. We also demonstrate that the natural graphical representation based on the Hausdorff distance is more reasonable than the consensus tree for a recent public health threat, the influenza A (H7N9) viruses.
- Phylogeography of Cephalotaxus oliveri (Cephalotaxaceae) in relation to habitat heterogeneity, physical barriers and the uplift of the Yungui Plateau. [JOURNAL ARTICLE]
- Mol Phylogenet Evol 2014 Aug 23.
Habitat heterogeneity, physical barriers, and the uplift of the Yungui Plateau were found to deeply affect the phylogeographic pattern and evolutionary history of Cephalotaxus oliveri, a perennial conifer endemic to China. In this study, we explored the phylogeography using three chloroplast sequences (trnL-trnF, trnT-trnD and atpB-rbcL) in 22 natural populations of C. oliveri distributed throughout its range. The Yungui Plateau populations of C. oliveri were revealed to origin ca. 9.15 Ma by molecular clock estimation, which is consistent with rapid uplift of the Qinghai-Tibetan Plateau (QTP) ca. 8-10 Ma. Additionally, geological effects of the Yungui Plateau were suggested to promote the rapid intra-specific differentiation of C. oliveri in the Pliocene and Early Pleistocene. The relatively low level of genetic diversity (h = 0.719, θ = 1.17 × 10(-3)) and high population differentiation (NST = 0.771 and GST = 0.642) implied restricted gene flow among populations, which was confirmed by the Nested Clade Analysis (NCA). Mismatch distribution and haplotypes network provided evidences of recent demographic population expansion. Furthermore, the statistical dispersal-vicariance analysis indicated that the center of origin was in Central China. The comparison of haplotype distribution patterns indicated that the regions of HNHPS and HBLD were the potential refugia during the Pleistocene ice ages. Our results highlighted that habitat heterogeneity and physical barriers presenting in a species range can predict genetic patterns.
- Phylogenetic Analysis at Deep Timescales: Unreliable Gene Trees, Bypassed Hidden Support, and the Coalescence/Concatalescence Conundrum. [JOURNAL ARTICLE]
- Mol Phylogenet Evol 2014 Aug 21.
Large datasets that include many taxa and many genes are required to solve difficult phylogenetic problems that are deep in the Tree of Life. Currently, two divergent systematic methods are applicable and commonly applied to such datasets: the traditional supermatrix approach (= concatenation) and "shortcut" coalescence methods (= coalescence methods wherein gene trees and the species tree are not co-estimated). When applied to ancient clades, these contrasting frameworks often produce congruent results, but in recent phylogenetic analyses of Placentalia (placental mammals), this is not the case, with proponents of coalescence arguing that their novel approach robustly supports several interordinal clades that have resisted consistent resolution using standard concatenation methods. A recent series of papers has alternatively disputed and defended the utility of shortcut coalescence methods at deep phylogenetic scales (Meredith et al., 2011; Song et al., 2012; Gatesy and Springer, 2013; Wu et al., 2013; Zhong et al., 2013, 2014; Springer and Gatesy, 2014). Here, we examine this exchange in the context of published phylogenomic data from Mammalia (183 loci; McCormack et al., 2012); in particular we explore two critical and related issues - the delimitation of data partitions ("genes") in coalescence analysis and hidden support that emerges with the combination of such partitions in phylogenetic studies. Hidden support - increased support for a clade in combined analysis of all data partitions relative to the support evident in separate analyses of the various data partitions, is a hallmark of the supermatrix approach and a primary rationale for concatenating all characters into a single matrix. In the most extreme cases of hidden support, relationships that are contradicted by all gene trees are supported when all of the genes are analyzed together. A valid fear is that shortcut coalescence methods might bypass or distort character support that is hidden in individual loci because small gene fragments are analyzed in isolation. Given the extensive database of molecular, phenotypic, and fossil data for Mammalia, the assumptions and applicability of shortcut coalescence methods can be assessed with rigor to complement a small but growing body of simulation work that has directly compared these methods to concatenation. We document several remarkable cases of hidden support in both supermatrix and coalescence paradigms and argue that in most instances, the emergent support in the shortcut coalescence analyses is an artifact. By referencing rigorous molecular clock studies of Mammalia, we suggest that inaccurate gene trees that imply unrealistically deep coalescences debilitate shortcut coalescence analyses of the placental dataset. We document contradictory coalescence results for Placentalia, and outline a critical conundrum that challenges the general utility of shortcut coalescence methods at deep phylogenetic scales. In particular, the basic unit of analysis in coalescence analysis, the coalescence-gene (a minimal non-recombining stretch of aligned genomes) is expected to shrink in size as more taxa are analyzed, but as the amount of data for reconstruction of a gene tree ratchets downward, the number of nodes in the gene tree that need to be resolved ratchets upward. One possible solution to this inevitable equation is to concatenate multiple coalescence-genes to yield "gene trees" that better match the species tree. However, this hybrid concatenation/coalescence approach, "concatalescence," contradicts the most basic biological rationale for performing a coalescence analysis in the first place. We discuss this reality in the context of recent simulation work that also suggests inaccurate reconstruction of gene trees is more problematic for shortcut coalescence methods than deep coalescence of independently segregating loci is for concatenation methods.
- Multigene eukaryote phylogeny reveals the likely protozoan ancestors of opisthokonts (animals, fungi, choanozoans) and Amoebozoa. [JOURNAL ARTICLE]
- Mol Phylogenet Evol 2014 Aug 21.
Animals and fungi independently evolved from the protozoan phylum Choanozoa, these three groups constituting a major branch of the eukaryotic evolutionary tree known as opisthokonts. Opisthokonts and the protozoan phylum Amoebozoa (amoebae plus slime moulds) were previously argued to have evolved independently from the little-studied, largely flagellate, protozoan phylum, Sulcozoa. Sulcozoa are a likely evolutionary link between opisthokonts and the more primitive excavate flagellates that have ventral feeding grooves and the most primitive known mitochondria. To extend earlier sparse evidence for the ancestral (paraphyletic) nature of Sulcozoa, we sequenced transcriptomes from six gliding flagellates (two apusomonads; three planomonads; Mantamonas). Phylogenetic analyses of 173-192 genes and 73-122 eukaryote-wide taxa show Sulcozoa as deeply paraphyletic, confirming that opisthokonts and Amoebozoa independently evolved from sulcozoans by losing their ancestral ventral groove and dorsal pellicle: Apusozoa (apusomonads plus anaerobic breviate amoebae) are robustly sisters to opisthokonts and probably paraphyletic, breviates diverging before apusomonads; Varisulca (planomonads, Mantamonas, and non-gliding flagellate Collodictyon) are sisters to opisthokonts plus Apusozoa and Amoebozoa, and possibly holophyletic; Glissodiscea (planomonads, Mantamonas) may be holophyletic, but Mantamonas sometimes groups with Collodictyon instead. Taxon and gene sampling slightly affects tree topology; for the closest branches in Sulcozoa and opisthokonts, proportionally reducing missing data eliminates conflicts between homogeneous-model maximum-likelihood trees and evolutionarily more realistic site-heterogeneous trees. Sulcozoa, opisthokonts, and Amoebozoa constitute an often-pseudopodial 'podiate' clade, one of only three eukaryotic 'supergroups'. Our trees indicate that evolution of sulcozoan dorsal pellicle, ventral pseudopodia, and ciliary gliding (probably simultaneously) generated podiate eukaryotes from Malawimonas-like excavate flagellates.
- Multigene phylogeny resolves deep branching of Amoebozoa. [JOURNAL ARTICLE]
- Mol Phylogenet Evol 2014 Aug 20.
Amoebozoa is a key phylum for eukaryote phylogeny and evolutionary history, but its phylogenetic validity has been questioned since included species are very diverse: amoebo-flagellate slime-moulds, naked and testate amoebae, and some flagellates. 18S rRNA gene trees have not firmly established its internal topology. To rectify this we sequenced cDNA libraries for seven diverse Amoebozoa and conducted phylogenetic analyses for 109 eukaryotes (17-18 Amoebozoa) using 60-188 genes. We conducted Bayesian inferences with the evolutionarily most realistic site-heterogeneous CAT-GTR model and maximum likelihood analyses. These unequivocally establish the monophyly of Amoebozoa, showing a primary dichotomy between the previously contested subphyla Lobosa and Conosa. Lobosa, the entirely non-flagellate lobose amoebae, are robustly partitioned into the monophyletic classes Tubulinea, with predominantly tube-shaped pseudopodia, and Discosea with flattened cells and different locomotion. Within Conosa 60/70-gene trees with very little missing data show a primary dichotomy between the aerobic infraphylum Semiconosia (Mycetozoa and Variosea) and secondarily anaerobic Archamoebae. These phylogenetic features are entirely congruent with the most recent major amoebozoan classification emphasising locomotion modes, pseudopodial morphology, and ultrastructure. However, 188-gene trees where proportionally more taxa have sparser gene-representation weakly place Archamoebae as sister to Macromycetozoa instead, possibly a tree reconstruction artefact of differentially missing data.
- Tracing the evolution of FERM domain of Kindlins. [JOURNAL ARTICLE]
- Mol Phylogenet Evol 2014 Aug 20.
Kindlin proteins represent a novel family of evolutionarily conserved FERM domain containing proteins (FDCPs) and are members of B4.1 superfamily. Kindlins consist of three conserved protein homologs in vertebrates: Kindlin-1, Kindlin-2 and Kindlin-3. All three homologs are associated with focal adhesions and are involved in Integrin activation. FERM domain of each Kindlin is bipartite and plays a key role in Integrin activation. A single ancestral Kindlin protein can be traced back to earliest metazoans, e.g., to Parazoa. This protein underwent multiple rounds of duplication in vertebrates, leading to the present Kindlin family. In this study, we trace phylogenetic and evolutionary history of Kindlin FERM domain with respect to FERM domain of other FDCPs. We show that FERM domain in Kindlin homologs is conserved among Kindlins but amount of conservation is less in comparison with FERM domain of other members in B4.1 superfamily. Furthermore, insertion of Pleckstrin Homology like domain in Kindlin FERM domain has important evolutionary and functional consequences. Important residues in Kindlins are traced and ranked according to their evolutionary significance. The structural and functional significance of high ranked residues is highlighted and validated by their known involvement in Kindlin associated diseases. In light of these findings, we hypothesize that FERM domain originated from a proto-Talin protein in unicellular or proto-multicellular organism and advent of multi-cellularity was accompanied by burst of FDCPs, which supported multi-cellularity functions required for complex organisms. This study helps in developing a better understanding of evolutionary history of FERM domain of FDCPs and the role of FERM domain in metazoan evolution.
- When everything converges: Integrative taxonomy with shell, DNA and venomic data reveals Conus conco, a new species of cone snails (Gastropoda: Conoidea). [JOURNAL ARTICLE]
- Mol Phylogenet Evol 2014 Aug 13.
Cone snails have long been studied both by taxonomists for the diversity of their shells and by biochemists for the potential therapeutic applications of their toxins. Phylogenetic approaches have revealed that different lineages of Conus evolved divergent venoms, a property that is exploited to enhance the discovery of new conotoxins, but is rarely used in taxonomy. Specimens belonging to the Indo-West Pacific Conus lividus species complex were analyzed using phenetic and phylogenetic methods based on shell morphology, COI and 28S rRNA gene sequences and venom mRNA expression and protein composition. All methods converged to reveal a new species, C. conco n. sp. (described in Supplementary data), restricted to the Marquesas Islands, where it diverged recently (∼3mya) from C. lividus. The geographical distribution of C. conco and C. lividus and their phylogenetic relationships suggest that the two species diverged in allopatry. Furthermore, the diversity of the transcript sequences and toxin molecular masses suggest that C. conco evolved unique toxins, presumably in response to new selective pressure, such as the availability of new preys and ecological niches. Furthermore, this new species evolved new transcripts giving rise to original toxin structures, probably each carrying specific biological activity.
- Mitochondrial genomes reveal the pattern and timing of marten (Martes), wolverine (Gulo), and fisher (Pekania) diversification. [JOURNAL ARTICLE]
- Mol Phylogenet Evol 2014 Aug 12.
Despite recent advances in understanding the pattern and timescale of evolutionary diversification in the marten, wolverine, fisher, and tayra subfamily Guloninae (Mustelidae, Carnivora), several important issues still remain contentious. Among these are the phylogenetic position of Gulo relative to the subgenera of Martes (Martes and Charronia), the phylogenetic relationships within the subgenus Martes, and the timing of gulonine divergences. To elucidate these issues we explored nucleotide variation in 11 whole mitochondrial genomes (mitogenomes) from eight gulonine species and two outgroup meline species. Parsimony, maximum likelihood, and Bayesian phylogenetic analyses yielded fully resolved and identical patterns of relationships with high support for all divergences. The generic status of Pekania (P. pennanti), the monophyly of the genus Martes containing M. flavigula (subgenus Charronia) to the exclusion of the genus Gulo (G. gulo), and the M. foina (M. americana (M. melampus (M. zibellina, M. martes))) phylogeny of the subgenus Martes were strongly supported. Dating analyses (BEAST) using a set of five newly applied fossil calibrations provided divergence times considerably younger than previous multigene mitochondrial estimates, but similar to multigene nuclear and nuclear-mitochondrial estimates. The 95% confidence (highest posterior density) intervals of our divergence times fell within those inferred from nuclear and nuclear-mitochondrial sequence data, and were markedly narrower than in earlier studies (whether nuclear, mitochondrial, or combined). Notably, and contrary to long-held beliefs, our findings indicate that fossils older than the Tortonian-Messinian transition (late Late Miocene) do not represent Martes, excluding from this genus its putative members from the Early, Middle, and early Late Miocene. This study demonstrates the high informativeness of the mitogenome for phylogenetic inference and divergence time estimation within Guloninae, and suggests that mitogenomes can be highly informative also for other clades at similar levels of evolutionary divergence.