Modeling and Measuring Tree-Reading Skills in Undergraduate and Graduate Students

Reading evolutionary trees is a challenging task for students. Item response theory was used to investigate a tree-reading skill system, and the different skills were found to be empirically distinguishable, although there was no evidence for the assumed hierarchy. The results are compared with a different approach by other authors.

Seeing the Woods for the Trees Again: Analyzing Evolutionary Diagrams in German and US University-Level Textbooks

Phylogenetic trees are important tools for teaching and understanding evolution, yet students struggle to read and interpret them correctly. In this study, we extend a study conducted by Catley and Novick (2008) by investigating depictions of evolutionary trees in US textbooks. We investigated 1197 diagrams from 11 German and 11 United States university textbooks, conducting a cross-country comparison and comparing the results with data from the 2008 study. A coding manual was developed based on the 2008 study, with extensions focused on additional important aspects of evolutionary trees. The US and German books showed only a low number of significant differences, typically with very small impacts. In both samples, some characteristics that can render reading trees more difficult or foster misconceptions were found to be prevalent in various portions of the diagrams. Furthermore, US textbooks showed fewer problematic properties in our sample than in the 2008 sample. We conclude that evolutionary trees in US and German textbooks are represented comparably and that depictions in US textbooks have improved over the past 12 years. As students are confronted with comparable depictions of evolutionary relatedness, we argue that findings and materials from one country should easily be transferable to the other.

Spanning the Globe – The Plant Phylogeny Poster (PPP) Project

Historically, wallcharts and posters created by botanical illustrators, often highly skilled artists, have played an important role in teaching botany at the university level. Large-scale panels and posters can visualize complex interrelationships and entire stories in a clear and appealing overview in graphs, tables, and diagrams. Carrying this concept of educational tools into the electronic era, the Plant Phylogeny Poster project uses this approach for displaying evolutionary relationships in systematic botany. The Angiosperm Phylogeny Poster (APP) displays, as phylogenetically arranged clades, the orders and families of flowering plants (with orders hyperlinked to APweb, Stevens, 2001–onwards), the Tracheophyte Phylogeny Poster (TPP) families and genera of ferns and gymnosperms, and the Bryophyte Phylogeny Poster (BPP) orders and families of liverworts, mosses, and hornworts. The portfolio currently also includes about 30 posters on individual orders and families of angiosperms. Each group within these evolutionary trees is matched with essentially relevant morphological features, biogeographic occurrences, and other information in compactly condensed text blocks. All posters are freely available online, some in more than 30 languages, coauthored by a team of more than 130 botanists. The posters are regularly updated, current literature is cited. The project is expanding steadily and rapidly.

Genetic Diversity of Natural Morchella spp. from the Southern Gansu Province Based on rDNA-ITS, China

Background: China is a mainland country rich in natural Morchella spp. resources. At present, about half of the natural Morchella spp. in the world has been recorded in China. The current study was aimed at the classification and cultivation of Morchella spp. This study provided a more accurate molecular trait for the systematic classification of Morchella spp. in southern Gansu Province, China.Methods: From April to May 2019. Based on the molecular biological analysis of 16 natural Morchella spp. strains collected from the southern Gansu province, China. the ITS fragments between transcripts of the rDNA gene were amplified by PCR and sequenced.Result: The results of BLAST comparison according to GenBank showed that the 16 tested strains of Morchella spp. were classified into 5 species, which were M.angusticeps, M.esculenta, M.elata, M.crapssipes and M.conica. According to the molecular evolutionary trees constructed by the Maximum-Parsimony method (MP) and the Neighbour-Joining method (NJ), the topological structures of the two molecular evolutionary trees were similar and the Bootstrap verification had a high support rate, indicating that the phylogenetic relationship had high credibility.

A 4-lineage statistical suite to evaluate the support of large-scale retrotransposon insertion data to reconstruct evolutionary trees

Retrophylogenomics makes use of genome-wide retrotransposon presence/absence insertion patterns to resolve questions in phylogeny and population genetics. In the genomics era, evaluating high-throughput data requires the associated development of appropriately powerful statistical tools. The currently used KKSC 3-lineage statistical test for evaluating the significance of data is limited by the number of possible tree topologies it can assess in one step. To improve on this, we have now extended the analysis to simultaneously compare 4-lineages, which now enables us to evaluate ten distinct presence/absence insertion patterns for 26 possible tree topologies plus 129 trees with different incidences of hybridization. Moreover, the new tool includes statistics for multiple ancestral hybridizations, ancestral incomplete lineage sorting, bifurcation, and polytomy. The test is embedded in a user-friendly web R-application (http://retrogenomics.uni-muenster.de:3838/hammlet/) and is available for use by the general scientific community.

Sphenodontian phylogeny and the impact of model choice in Bayesian morphological clock estimates of divergence times and evolutionary rates

Background The vast majority of all life that ever existed on earth is now extinct and several aspects of their evolutionary history can only be assessed by using morphological data from the fossil record. Sphenodontian reptiles are a classic example, having an evolutionary history of at least 230 million years, but currently represented by a single living species (Sphenodon punctatus). Hence, it is imperative to improve the development and implementation of probabilistic models to estimate evolutionary trees from morphological data (e.g., morphological clocks), which has direct benefits to understanding relationships and evolutionary patterns for both fossil and living species. However, the impact of model choice on morphology-only datasets has been poorly explored. Results Here, we investigate the impact of a wide array of model choices on the inference of evolutionary trees and macroevolutionary parameters (divergence times and evolutionary rates) using a new data matrix on sphenodontian reptiles. Specifically, we tested different clock models, clock partitioning, taxon sampling strategies, sampling for ancestors, and variations on the fossilized birth-death (FBD) tree model parameters through time. We find a strong impact on divergence times and background evolutionary rates when applying widely utilized approaches, such as allowing for ancestors in the tree and the inappropriate assumption of diversification parameters being constant through time. We compare those results with previous studies on the impact of model choice to molecular data analysis and provide suggestions for improving the implementation of morphological clocks. Optimal model combinations find the radiation of most major lineages of sphenodontians to be in the Triassic and a gradual but continuous drop in morphological rates of evolution across distinct regions of the phenotype throughout the history of the group. Conclusions We provide a new hypothesis of sphenodontian classification, along with detailed macroevolutionary patterns in the evolutionary history of the group. Importantly, we provide suggestions to avoid overestimated divergence times and biased parameter estimates using morphological clocks. Partitioning relaxed clocks offers methodological limitations, but those can be at least partially circumvented to reveal a detailed assessment of rates of evolution across the phenotype and tests of evolutionary mosaicism.

Novel Anaplasma Variants in Small Ruminants From Central China

Anaplasma capra is an emerging zoonotic pathogen that pose a risk to the health of human and veterinary animal. Numerous variants in a variety of domestic and wild animals had been reported since its discovery and confirmation in humans in 2015 and its first detection from goat blood during 2012–2013. In order to find out more A. capra variants data of A. capra in central China, 16S rRNA, gltA, groEL, and msp4 genes of this pathogen were amplified from sheep and goat samples collected during 2011–2015 and phylogenetic analysis of these sequences were conducted. The results of 16S rRNA and gltA manifested that partial sequences obtained in this study were 100% identical with A. capra isolates, while phylogenetic analysis results of groEL and msp4 showed that the obtained sequences were independent with all other Anaplasmas, formed separate branches on the evolutionary trees. What needed to be emphasized was that the 16S rRNA and gltA gene sequences of X51 (KX505302 and KX450269), a sample from Shandong in 2011, were found to be 100% identical with A. capra. Therefore, we could speculate that the occurrence of A. capra may be earlier than its first discovery and report. And the A. capra isolates in central China were novel variants which were different from known genotypes.

Distance metrics for ranked evolutionary trees

Genealogical tree modeling is essential for estimating evolutionary parameters in population genetics and phylogenetics. Recent mathematical results concerning ranked genealogies without leaf labels unlock opportunities in the analysis of evolutionary trees. In particular, comparisons between ranked genealogies facilitate the study of evolutionary processes of different organisms sampled at multiple time periods. We propose metrics on ranked tree shapes and ranked genealogies for lineages isochronously and heterochronously sampled. Our proposed tree metrics make it possible to conduct statistical analyses of ranked tree shapes and timed ranked tree shapes or ranked genealogies. Such analyses allow us to assess differences in tree distributions, quantify estimation uncertainty, and summarize tree distributions. We show the utility of our metrics via simulations and an application in infectious diseases.

Evolutionary Study of the Crassphage Virus at Gene Level

crAss-like viruses are a putative family of bacteriophages recently discovered. The eponym of the clade, crAssphage, is an enteric bacteriophage estimated to be present in at least half of the human population and it constitutes up to 90% of the sequences in some human fecal viral metagenomic datasets. We focused on the evolutionary dynamics of the genes encoded on the crAssphage genome. By investigating the conservation of the genes, a consistent variation in the evolutionary rates across the different functional groups was found. Gene duplications in crAss-like genomes were detected. By exploring the differences among the functional categories of the genes, we confirmed that the genes encoding capsid proteins were the most ubiquitous, despite their overall low sequence conservation. It was possible to identify a core of proteins whose evolutionary trees strongly correlate with each other, suggesting their genetic interaction. This group includes the capsid proteins, which are thus established as extremely suitable for rebuilding the phylogenetic tree of this viral clade. A negative correlation between the ubiquity and the conservation of viral protein sequences was shown. Together, this study provides an in-depth picture of the evolution of different genes in crAss-like viruses.