Chapter Four · failure evidence

What Phylogenetic Tree Reconstruction got wrong, from 42 dissertations

The records evaluate various computational, algorithmic, and data preparation strategies for phylogenetic tree inference across diverse biological and linguistic datasets. Many attempts failed or were rejected due to insufficient phylogenetic signal from restricted markers, reticulate evolutionary events violating tree structures, matrix filtering artifacts, and inaccurate distance approximations. These records come from PhD theses at 16 institutions, 2021 to 2026. Each links to its thesis. They were extracted by language models reading the full text, so treat each as a lead to read, not a verdict.

Single markers and isolated partitions lack sufficient phylogenetic signal and create erroneous groupings

9 theses · 8 institutions

Relying on individual genes, single morphological features, or restricted sequence regions produces unresolved polytomies and weak branch support. These narrow data sources are often distorted by recombination, horizontal gene transfer, and homoplasy compared to whole genomes or multi-locus transcriptomic datasets.

Tried and failed

single-locus phylogenetic tree reconstruction applied to species tree inference in amphibians. Outcome: no signal. Reason: insufficient phylogenetic resolution leading to discordance and low posterior support

Adaptation during range expansion: a phylogenetic, population genetic, and physiological perspective · Cornell

Considered and rejected

Considered and rejected: Rejected individual nuclear gene trees as standalone phylogenetic markers due to polytomies and weak nodal support.

Exome analyses and species delimitations of the Heteromys pictus-spectabilis species complex · Texas Tech

Tried and failed

phylogenetic reconstruction using internal coding sequences applied to endogenous retrovirus subfamily classification. Outcome: no signal. Reason: coding sequences provided insufficient granularity to resolve subfamilies compared to non-coding terminal repeats

RECOMBINATION-MEDIATED REGULATORY EVOLUTION OF HUMAN ENDOGENOUS RETROVIRUS HERVH · Cornell

Tried and failed

phylogenetic inference from single anatomical partition applied to morphological evolutionary tree reconstruction. Outcome: worse than baseline. Reason: isolated postcranial characters lacked sufficient phylogenetic signal and introduced severe homoplasy-driven misplacements

Effects of Additional Postcranial Data on the Topologies of Early Eocene Primate Phylogenies · UT Austin

Tried and failed

concatenating top marker genes for phylogenetic distance applied to microbial eukaryotic genome taxonomic classification. Reason: diminishing returns with plateauing resolution unable to match whole-genome sequence resolution

Expanding The Bioinformatics Toolbox for Diversity and Taxonomic Studies of Microbial Eukaryotic Pathogens · Georgia Tech

Considered and rejected

Considered and rejected: Rejected using mitochondrial genomes for deep heterobranch phylogenetic nodes because they perform poorly compared to transcriptomic datasets.

An inordinate fondness for slugs: Phylogenomics of the diverse gastropod clade Heterobranchia, a group key to our understanding of the evolution of shell reduction and loss · Harvard

Tried and failed

single-gene marker phylogenetic classification applied to bacterial strain taxonomic identification. Outcome: did not generalise. Reason: horizontal gene transfer and recombination caused single-marker phylogeny to produce non-monophyletic groups

Bacterial Plant Pathogen Identification using Genomics and Metagenomics · Virginia Tech

Considered and rejected

Considered and rejected: Rejected classifying higher bacterial ranks and lineage divergences using 16S rRNA gene fragments alone due to insufficient phylogenetic resolution and primer bias, opting instead for genome-wide relative evolutionary divergence (RED).

Phylogeny and metabolism ofEndomicrobiaceae and ElusimicrobiaceaeExploring reductive genome evolution in two hostassociated lineages of Elusimicrobiota Phylogenie und Stoffwechsel von Endomicrobiaceae und ElusimicrobiaceaeErkundung von reduktiver Genomevolution in zwei Wirt-assoziierten Linien von Elusimicrobiota · open_UMR Marburg DSpace 10.0

Tried and failed

phylogenetic classification using single isolated morphological markers applied to dialect subgrouping and classification. Reason: progressive aspect markers were conflated with indicative markers, leading to erroneous lineage groupings

A Diachronic Analysis of Western Armenian Verbal Morphology · Penn

Strictly bifurcating tree models fail when evolutionary processes involve reticulation, introgression, or lateral transfer

8 theses · 5 institutions

Modeling admixed populations, hybridizing species, or mobile genetic elements on simple branching trees violates core evolutionary assumptions. These reticulate scenarios collapse tree resolution and necessitate explicit phylogenetic network or neighbor-net approaches.

Tried and failed

unadmixed phylogenetic tree modeling applied to admixed population placement. Reason: the lineage violates bifurcating tree assumptions due to being an admixed allelic sink

Establishing a Genetic System for Studying Cannabis Domestication · Harvard

Tried and failed

strictly bifurcating phylogenetic tree inference applied to hybridising and introgressing lineages. Outcome: no signal. Reason: reticulate evolution and extensive introgression violate strict tree-like branching assumptions

Phylogeny, biogeography, and hybridization in Baptisia (Fabaceae) : genomic insights into evolutionary dynamics and species boundaries · UT Austin

Tried and failed

phylogenetic stemmatology and genealogical classification applied to historical manuscript variant networks. Outcome: did not generalise. Reason: hybrid or contaminated textual variants prevented placement into standard tree-based lineages

Das Buch von geistlicher Armut: Überlieferung, Armutskonzept, Rezeption · Harvard

Tried and failed

bifurcating tree phylogenetic reconstruction applied to lineages with rampant horizontal gene flow. Outcome: no signal. Reason: widespread introgression breaks the fundamental assumption of a strictly branching evolutionary history

Applications of Coalescent Theory to Introgression Inference and Analysis of Genomic Studies of Sex and Sexuality · Harvard

Considered and rejected

Considered and rejected: Rejected standard haplotypic ancestral state reconstruction on bifurcating trees due to pervasive historical gene flow and incomplete lineage sorting.

The genomic basis of repeated adaptation in deer mice · Harvard

Considered and rejected

Considered and rejected: Rejected standard bifurcating phylogenetic trees alone, adopting phylogenetic network analyses (SplitsTree Neighbor-Net) due to reticulate relationships and subgenome exchanges

Genotypes to Phenotypes: Genomic attributes that impact Genome-wide Associations in peanut (Arachis hypogaea. L). · Iowa State

Considered and rejected

Considered and rejected: Rejected dendrogram-based phylogenetic tree methods (e.g., ViPTree, GRAViTy) for classifying prophages because they flatten evolutionary relationships into a single hierarchy and cannot represent horizontal gene transfer and genome mosaicism.

Anti-phage defense as a driver of molecular innovation · MIT

Tried and failed

strict phylogenetic cladistic tree modeling applied to dialect evolution with lateral transfer. Outcome: did not generalise. Reason: Strict hierarchical trees cannot capture lateral transfer, reticulation, or horizontal contact dynamics.

A Diachronic Analysis of Western Armenian Verbal Morphology · Penn

Aggressive taxon pruning and character filtering destabilize consensus trees and discard informative phylogenetic signal

5 theses · 5 institutions

Removing ambiguous taxa or suspected homoplastic characters frequently eliminates essential phylogenetic information and causes severe consensus tree instability. Similarly, strict filtering of missing data reduces informative sites and creates topological conflict across clades.

Tried and failed

maximum parsimony phylogenetic consensus analysis applied to morphological character matrix with missing data. Outcome: unstable. Reason: fragmentary and unstable rogue taxa collapsed resolution across all internal clades in the consensus tree

A NEW PHYLOGENETIC ANALYSIS AND CHARACTER MATRIX REASSESSMENT FOR THE COELACANTHS (SARCOPTERYGII: COELACANTHIFORMES) · Cornell

Tried and failed

aggressive taxon pruning to resolve consensus polytomies applied to morphological maximum parsimony phylogenetic analysis. Outcome: unstable. Reason: removes highly complete, informative taxa and causes severe tree consensus instability

A NEW PHYLOGENETIC ANALYSIS AND CHARACTER MATRIX REASSESSMENT FOR THE COELACANTHS (SARCOPTERYGII: COELACANTHIFORMES) · Cornell

Tried and failed

filtering noisy features prior to parsimony inference applied to phylogenetic matrix resolution across diverse taxa. Outcome: data insufficient. Reason: removing suspected homoplastic characters severely reduced information content, preventing relationship resolution among taxa

A NEW PHYLOGENETIC ANALYSIS AND CHARACTER MATRIX REASSESSMENT FOR THE COELACANTHS (SARCOPTERYGII: COELACANTHIFORMES) · Cornell

Considered and rejected

Considered and rejected: Excluded Poxviridae from definitive replisome/transcription phylogenies due to unstable phylogenetic placement across diagnostic trees

Comparative and Evolutionary genomics of Nucleocytoviricota · Virginia Tech

Considered and rejected

Considered and rejected: Eliminated phylogenetic loci that produced more than 10 paralogs or displayed paralog trees without clear structure (unresolved homology).

Mistakes and Small Steps Can Take You Far: Exploring Fern Variation and Biogeography in Cheilanthes (Pteridaceae), with a Focus on Spore Diversity and Range Expansion in Cheilanthes distans · DukeSpace

Tried and failed

strict missing data filtering of loci applied to phylogenetic alignment matrix. Outcome: worse than baseline. Reason: filtering reduced total informative sites, decreasing branch support and creating topological conflict

The evolutionary history and diversity of the Mickey Mouse Plants (the genus Ochna) · Imperial

Considered and rejected

Considered and rejected: Evaluating single global phylogenetic trees across all taxa, discarded in favor of partitioned subset analyses because distant taxa artificially reduced informative site weights via homoplasy

Taxonomic affiliations and phylogeographic origins of melanoploid grasshoppers as revealed by molecular phylogenetic analyses. · oURspace

Fast heuristic algorithms and parsimony criteria yield suboptimal tree likelihoods and unresolved clades

5 theses · 4 institutions

Heuristic tree search tools like FastTree2 produce likelihood scores that fall substantially short of robust probabilistic frameworks like IQ-TREE 2 and RAxML. In addition, maximum parsimony models often fail to resolve character partitions and yield less resolved topologies than probabilistic alternatives.

Tried and failed

maximum parsimony phylogenetic reconstruction across morphological partitions applied to fossil primate morphological dataset. Outcome: worse than baseline. Reason: produced a less resolved consensus tree and misclassified target taxon compared to baseline PAUP implementation

Effects of Additional Postcranial Data on the Topologies of Early Eocene Primate Phylogenies · UT Austin

Considered and rejected

Considered and rejected: FastTree2 was rejected for comprehensive phylogenetic inference and cross-comparisons because its likelihood scores were substantially worse than IQ-TREE 2, RAxML, and MrBayes.

Discovery and characterization of diverse microbial RNA-guided systems · MIT

Considered and rejected

Considered and rejected: Rejected FastTree2 for comprehensive phylogenetic cross-comparisons due to substantially worse likelihood scores than IQ-TREE 2, RAxML, or MrBayes.

Data Driven Discovery of Modular Biological Systems · MIT

Considered and rejected

Considered and rejected: Rejected parsimony in favor of maximum likelihood for phylogenetic reconstruction because ML provides a probabilistic model rather than minimal change steps.

Quantitatively Investigating the Genetic Response of the Euryhaline Sailfin Molly (Poecilia latipinna) to Manipulations of Environmental and Dietary Magnesium · YorkSpace

Considered and rejected

Considered and rejected: Bayesian inference and Maximum Likelihood were rejected for primary morphological phylogenetic analyses due to computational intractability and reliance on questionable prior substitution/rate models for morphological data.

The Integration Of Morphology, Variation, And Phylogenetics To Better Understand Fossil Taxa And Their Modern Relatives · Penn

Approximate distance metrics and k-mer sketching distort pairwise relationships and hierarchical topologies

4 theses · 3 institutions

Heuristic distance calculations and default MinHash sketching sizes fail to preserve true edit distances and cophenetic correlations. These approximations introduce intra-clade noise and place closely related lineages into incorrect topological arrangements.

Tried and failed

approximate sequence distance via k-mer sketching applied to phylogenetic graph edge construction. Outcome: worse than baseline. Reason: Inconsistent distance estimations produced incorrect parent-child relationships compared to exact edit distance

Graph-Based Computational Approaches for Modeling Viral Evolution · Virginia Tech

Tried and failed

approximate pairwise distance estimation for hierarchical clustering applied to genome-scale phylogenetic reconstruction. Outcome: worse than baseline. Reason: heuristic distance approximations failed to accurately preserve hierarchical topology and cophenetic correlation across ranks

Tackling the current limitations of bacterial taxonomy with genome-based classification and identification on a crowdsourcing Web service · Virginia Tech

Tried and failed

hyperbolic graph embedding of accessibility matrix applied to phylogenetic relationship reconstruction. Reason: hyperbolic embedding placed closely related clusters nearer to distant nodes than expected ground-truth topology

Geometric Methods for Quantitative Analysis of Romance Languages · Harvard

Tried and failed

MinHash sketching distance estimation applied to closely related fungal phylogenetic reconstruction. Outcome: worse than baseline. Reason: Default sketch size caused excessive intra-clade variation and misplaced phylogenetic topology compared to alignment methods

Computational Genomics to Characterize the Distribution, Diversity and Drug Resistance of Fungal Pathogens · Georgia Tech

Outgroup and midpoint rooting techniques are biased by long branches and rate heterogeneity

3 theses · 3 institutions

Distant outgroups and divergent homologous lineages introduce long-branch attraction artifacts and recombination signals that distort root placement. Midpoint rooting and minimal ancestor deviation also fail when large rate differences across lineages systematically skew the inferred root position.

Tried and failed

outgroup rooting for phylogenetic tree reconstruction applied to divergent homologous gene families. Reason: long-branch attraction artifacts caused inconsistent and unresolved root placements across gene trees

Global distribution and ancient evolution of far-red photosynthesis · Imperial

Tried and failed

outgroup rooting with distant lineages applied to bacterial phylogenetic tree inference. Outcome: unstable. Reason: recombination events on long branches distorted phylogenetic signals and root placement

Genomic insights into the host range and interspecies transmission dynamics of Staphylococcus aureus · Cambridge

Considered and rejected

Considered and rejected: Rejected minimal ancestor deviation (MAD) and midpoint rooting for the global MMP tree because wide differences in branch lengths between metazoan and prokaryotic lineages systematically biased roots toward prokaryotes

Bridging the gap between microbial and metazoan evolutionary history · MIT

Left open by the authors

Problems the authors named and did not get to.

Left open

Evaluate MSA Transformer representations against phylogenetic trees and patristic distances rather than simple Hamming distances across protein sequences. Blocker: None

Revealing and exploiting coevolution through protein language models · EPFL

Left open

Investigate phylogenetic relationships among Ambystoma species to clarify morphological evolution patterns. Blocker: Lacks specific target dataset, genetic/morphological markers, or concrete phylogenetic methodology

Changes in central Texas herpetofauna during the late Quaternary : an examination of lizards and salamanders from Hall’s Cave · UT Austin

Left open

Perform a comprehensive co-evolutionary analysis of host-parasite phylogenies across all bee host families using resolved host trees. Blocker: Detailed host phylogenetic trees across all bee host families were not yet available

THE EVOLUTION OF BROOD PARASITISM IN BEES AND OTHER ANIMALS · Cornell

Left open

Develop cytonuclear coevolution detection methods that account for incomplete lineage sorting, hybridization, and gene duplication in phylogenomics. Blocker: No concrete mathematical or algorithmic formulation specified for incorporating ILS/hybridization into ERC frameworks

Cytonuclear coevolution investigations in papilionoid legumes and medicago (fabaceae) · UT Austin

Left open

Gather phylogenetic and evolutionary evidence on the original selective pressures and timeline of pain origination. Blocker: Task is an open-ended biological/evolutionary research direction lacking concrete methodology or clear data scope

Foundations of pain · UT Austin

Left open

Compare phylogenetic or fossil occurrence patterns with reconstructed river capture landscapes to empirically test geomorphic controls on speciation rates. Blocker: Lacks specific target taxa, geographic locations, and concrete datasets to compare against landscape models.

Dynamic river networks drive landscape change and biological evolution · MIT

Left open

Cluster bacterial host source classes using phylogenetic trees to reduce classification output space complexity. Blocker: None

Applications of Machine Learning in Source Attribution and Gene Function Prediction · Virginia Tech

Left open

Develop robust machine learning algorithms for graphical models such as Ising models or phylogenetic trees with malicious nodes. Blocker: Task is framed as a broad research direction without specific algorithms, performance targets, or detailed formulations

Statistical Inference in the Differential Privacy Model · Cornell

Left open

Extend the PhyNE MCMC framework to jointly estimate niche model parameters and phylogenetic tree topology and branch lengths. Blocker: None

Phylogenetic Niche Modeling · Virginia Tech

Left open

Implement hierarchical or multi-scale flow matching architectures in PhylaFlow to scale phylogenetic tree inference to datasets beyond 50 leaves. Blocker: None

Foundation Model Guided Flow Matching on Tree Manifold for Differentiable Phylogenetics · Harvard

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