Biology subjects

Schwarz, M.

Publications and source records attributed to Schwarz, M..

At least 19 recordsLinked to original sources

bioRxiv2026

Developmental Trajectories of Dynamic Brain Network Organization and Their Alteration in Tourette Syndrome

Typical brain network maturation involves an increase in network flexibility and hemispheric specialization. Tourette syndrome (TS) disrupts these trajectories, with tic severity potentially modulating deviations. This study examined theta-band EEG source connectivity states in typically developing children and children with TS. We assessed age-related trajectories and the impact of tic severity using generalized linear modeling, accounting for sex and multiple comparisons. K-means clustering identified four recurrent source connectivity states (A-D), with metrics including Coverage, representing state prevalence (proportion of time spent in each state), Average Dwell Time, an index of state stability (mean duration of stable persistence of each state), and Transition Rate Per Minute, reflecting global network flexibility (frequency of state switches per minute). In healthy controls (HC), typical maturation was characterized by increased left intra-hemisphere connectivity state stability and prevalence, decreased diffuse connectivity state stability, and rising network flexibility. TS patients exhibited deviant trajectories, including age-dependent decreasing global network flexibility across subgroups stratified by tic severity and marginally divergent diffuse activity patterns, with high-severity cases showing increased diffuse connectivity state stability. The normative patterns suggest typical motor development requiring dynamic network reconfiguration and hemispheric specialization, processes that appear altered in TS. TS patients exhibit age-dependent network rigidity across severity subgroups, as reflected by decreased transition rates, alongside severity- modulated network imbalances, indicating that tic disorders disrupt mechanisms of brain network maturation underlying motor control. These findings suggest that atypical trajectories of network stability and flexibility represent a key feature of tic pathophysiology, highlighting the role of altered network dynamics in TS during maturation.

neuroscience↗

bioRxiv2026

PIEZO1 upregulation in spinal cord astrocytes during MOG 35-55 -induced EAE correlates with ECM remodeling

BackgroundExtracellular matrix (ECM) remodeling is increasingly recognized as an important component of neuroinflammatory pathology in multiple sclerosis (MS), yet the mechanisms by which CNS cells sense and respond to alterations in their mechanical environment and the spatial across which mechanical changes can influence cellular behavior remain poorly understood. Piezo1 is a mechanosensitive ion channel that regulates cellular responses to mechanical stimuli and has recently emerged as a potential modulator of neuroinflammation. MethodsExperimental autoimmune encephalomyelitis (EAE) was induced in C57BL/6 wildtype mice using myelin oligodendrocyte glycoprotein (MOG):35-55. Immunohistochemical analyses were performed in spinal cord gray matter (GM), normal-appearing white matter (NAWM), and white matter lesion (LES) regions to assess ECM remodeling, total Piezo1 expression, and astrocyte-specific Piezo1 expression during acute and chronic EAE stages. Correlations with clinical EAE severity were determined. In parallel, mixed primary murine glial cultures were exposed to substrates of different stiffness and analyzed by transcriptomic profiling to investigate mechanobiological responses in vitro. ResultsECM-associated proteins, including glial fibrillary acidic protein (GFAP), fibronectin-1 and matrix metalloproteinase-3 (MMP3), were regionally upregulated during EAE, indicating widespread tissue remodeling beyond focal inflammatory lesions. Total Piezo1 expression was increased within lesions and transiently elevated in GM, whereas astrocyte-specific Piezo1 remained persistently upregulated during both acute and chronic EAE. Astrocytic Piezo1 expression correlated closely with ECM remodeling and clinical EAE severity, particularly in GM and NAWM. Notably, both total and astrocyte-specific Piezo1 showed stronger associations with clinical disability than classical inflammatory markers. Transcriptomic analysis revealed pronounced stiffness-dependent responses in glial cells, including alterations in extracellular matrix organization, cytokine signaling, cell adhesion, and proliferative pathways. ConclusionsOur findings identify astrocytic Piezo1 as a prominent component of neuroinflammatory tissue remodeling during EAE. The close association of Piezo1 with ECM alterations, clinical disease severity, and stiffness-dependent glial responses supports a link between neuroinflammation and mechanosensory signaling. These results highlight mechanosensation as a potentially important contributor to CNS pathology and establish Piezo1 alteration as a candidate biomarker for neuroinflammatory disease.

Cell Biology↗

bioRxiv2025

Glutamine Availability Impacts Lymphatic Endothelial Cell Glycolysis and Lymphangiogenesis in Hypoxic Environments

Dysfunctional lymphangiogenesis is a component of several diseases, including secondary lymphedema, allergic asthma, and solid malignancies. These vessels are ineffective at draining interstitial fluid, resulting in secondary complications such as edema, increased inflammation, slowed wound healing, and, for cancer patients, increased risk of metastasis. Hypoxic microenvironments drive dysfunctional vessel growth by upregulating vascular endothelial growth factor receptors, migratory signaling pathways, and glycolytic metabolism. Despite the potential benefits of normalizing lymphatic vasculature, most treatments for vascular normalization focus on blood vasculature, ignoring the unique properties of lymphatic endothelial cells (LECs). Moreover, previous targets for vascular normalization center around vascular endothelial growth factors, which risk adverse side effects. To address these issues, we approached lymphatic normalization from a metabolic perspective. In this study, we investigated the impact of glutamine availability on factors critical to lymphangiogenesis, including glycolysis, cell proliferation, and migration. We found that increasing the concentration of glutamine in media results in increased lactate production and the expression of glycolytic genes HK2, GLUT1, and GLUT3 under hypoxia. The presence of glutamine also encouraged LEC proliferation, while blocking glutamine transport reduced lactate production, HK2 expression, and slowed collective LEC migration. In a 2D vessel formation assay, we found that glutamine increased vessel formation in normoxic conditions but lowered vessel connectivity in hypoxic conditions, reflecting the dysfunction seen in hypoxic diseases. However, attenuating glycolysis by blocking glutamine transport caused LECs to form longer, interconnected vascular networks. This study reveals that glutamine availability can modulate LEC glycolysis, and therefore lymphangiogenesis, in a hypoxia-dependent manner.

cell biology↗

bioRxiv2025

Context-Dependent Adaptation in Structured Environments

Adaptive evolution often leads to niche specialization, but successful colonization of a new niche can depend as much on ecological context as on genetic change. This is especially true in spatially structured environments, where the physical construction of habitat and the order of arrival of mutants can shape evolutionary outcomes. In static broth cultures, the air-liquid interface (ALI) provides a high-oxygen niche typically colonized by mat-forming mutants. In Pseudomonas fluorescens, a range of single mutations that upregulate cellulose production give rise to "wrinkly spreader" (WS) types--canonical niche specialists that out-compete ancestral types at the ALI. Yet we discover that this is a half-truth: WS mutants frequently fail to establish when introduced alone at low density, but co-culture with ancestral types rescues colonization. Microscopy and model simulations show that ancestors physically scaffold the ALI, enabling stable attachment and facilitating the in situ emergence of an array of genetically diverse WS mutants. Ancestors later disperse, vacate the niche allowing WS mutant expansion. This transient asymmetric interaction reveals that even strongly adaptive mutations may require ecological facilitation to succeed. More broadly, our findings challenge simple narratives of adaptive replacement and underscore how transient ecological dependencies can shape the trajectory of evolutionary change.

evolutionary biology↗

bioRxiv2025

Amino acid restriction sensitizes lung cancer cells toferroptosis via GCN2-dependent activation of the integratedstress response

Lung cancer cells are vulnerable to iron-dependent oxidation of phospholipids leading to ferroptosis, a process countered by glutathione peroxidase-4 that converts lipid hydroperoxides to lipid alcohols using glutathione as reducing agent. Since ferroptosis-inducing agents are in clinical development, identifying modifiers of ferroptosis susceptibility is warranted. Here, we investigate the impact of amino acids on susceptibility to buthionine sulfoximine (BSO), a glutamate-cysteine ligase inhibitor that blocks biosynthesis of glutathione. We found that reduced amounts of amino acids other than cysteine increased the sensitivity to BSO and other ferroptosis-inducing agents, in a panel of mouse and human lung cancer cells, without affecting glutathione production. Activation of the amino acid sensor protein GCN2 and the integrated stress response lowered the threshold for lipid peroxidation by stimulating ATF4-dependent mitochondrial respiration. The finding has implications for lung cancer metabolism and raises the possibility of using protein restricted diets in combination with ferroptosis-inducing agents as cancer therapies.

cancer biology↗

bioRxiv2024

Expanding the CarD interaction network: CrsL is a novel transcription factor in Mycobacterium smegmatis

Bacterial transcription regulation is critical for adaptation and survival. CarD is an essential transcription factor in mycobacteria involved in regulation of gene expression. We searched for CarD interaction partners in the model organism Mycobacterium smegmatis and identified two proteins: ApeB (MSMEG_5828) and an uncharacterized protein, which we named CrsL (MSMEG_5890). While ApeB interacted with CarD only when CarD was overexpressed, CrsL associated with CarD at its physiological levels. CrsL is a 5.7 kDa protein shown by NMR to be intrinsically disordered. CrsL homologs are present in actinobacteria including pathogenic species such as Mycobacterium tuberculosis. CrsL directly interacts with CarD and binds RNAP. ChIP-seq showed that CrsL associates with promoters of actively transcribed genes and [~]75 % of these regions are also associated with CarD. RNA-seq showed [~]50% and [~]66% overlap in differentially expressed genes between CrsL and CarD knockdowns during exponential and stationary phases, respectively. CrsL represses expression of DesA desaturase (MSMEG_5773) and DEAD/DEAH-box RNA helicase MSMEG_1930, which are important for adaptation to cold stress. Furthermore, CrsL promotes the growth of M. smegmatis at elevated temperature. In summary, this study identifies CrsL as a novel actinobacterial transcription factor and provides a basis for its further investigation.

microbiology↗

bioRxiv2024

HelD is a Global Transcription Factor Enhancing Gene Expression in Rapidly Growing Mycobacteria

HelD protein, also named HelR (encoded by MSMEG_2174 in Mycobacterium smegmatis), interacts with mycobacterial RNA polymerase (RNAP) and affects rifampicin resistance in Mycobacterium abscessus. Here, we provide data on rifampicin resistance and helD presence in the genomes of other clinically relevant nontuberculous mycobacteria. We show that helD is primarily found in rapidly growing mycobacteria, such as M. smegmatis, where we detected HelD at a subset of promoters that can also associate with CarD and RbpA. Transcriptome analysis of a helD deletion strain using RNA-seq revealed that HelD enhances gene expression during exponential growth and decreases it in stationary phase, during which we observed reduced levels of CarD, RbpA, and GTP, the initiation nucleotide for the majority of M. smegmatis transcripts. We propose a model in which HelD releases abortive RNAP complexes and confirm that HelD dissociates RNAP from the promoter in vitro. HelD not only helps mycobacteria overcome rifampicin treatment but also supports efficient transcription during rapid growth, which indicates a dual role of this transcription regulator.

microbiology↗

bioRxiv2024

Aging promotes lung cancer metastasis through epigenetic ATF4 induction

Lung cancer is primarily a disease of the elderly. Despite shared molecular changes between aging and cancer 1 - such as permissive chromatin states and deregulated protein homeostasis - studies on physiologically aged models of human lung cancer are lacking. Here, we show that aging alters the progression of KRAS-driven non-small cell lung cancer (NSCLC), promoting metastasis while suppressing primary lung tumor growth. Clinically, a multicenter analysis of all consecutively diagnosed NSCLC cases in Western Sweden over a 3-year period confirmed increased metastasis and smaller primary tumor size with age in KRAS-driven NSCLC. In addition, primary lung tumor cultures derived from older mice demonstrated an increased metastatic phenotype. Unbiased transcriptomic and epigenomic analyses identified ATF4, a major arm of the unfolded protein response (UPR), as a driver of aging-induced lung cancer metastasis. Furthermore, we found that the age-associated increase in ATF4 fuels metastatic dissemination through metabolic rewiring, including increased glutaminolysis. Finally, we report that pharmacological inhibition of glutaminase effectively suppressed aging-induced metastasis. Our findings suggest a novel adjuvant therapy for human lung cancer by targeting aging-induced metabolic plasticity, highlighting the need to consider the biology of aging in the development of cancer therapy.

cancer biology↗

bioRxiv2024

Lethal Disruption of the Symbiotic Gut Community in Eastern Subterranean Termite Caused by Boric Acid

AbstractThe Eastern subterranean termite, Reticulitermes flavipes (Kollar), is a significant pest, causing extensive damage to structures that amount to substantial economic losses. Traditional termite control methods have utilized boric acid, known for its broad-spectrum insecticidal properties, yet its impact on termite gut microbiomes and the implications of such effects remain understudied. Our study evaluates the dose-dependent mortality of R. flavipes upon being provided boric acid treated filter papers and investigates the resulting dysbiosis within the termite gut microbiome. Consistent with reports from other insects, mortality increased in a dose-dependent manner, with the highest boric acid concentration (203.7 {micro}g/cm2 of filter paper) significantly reducing termite survival. 16S rRNA gene sequencing of the gut microbiome revealed notable shifts in composition, indicating boric acid-induced dysbiosis. Aside from an overall decrease in microbial diversity, the relative abundance of some symbionts essential for termite nutrition decreased in response to higher boric acid concentrations, while several putative pathogens increased. Our findings extend the understanding of boric acids mode of action in termites, emphasizing its effect beyond direct toxicity to include significant microbiome modulation that can have dire effects on termite biology. Considering its potential to induce dysbiosis and potentially augment the effectiveness of entomopathogens, our study supports the continued use of boric acid and related compounds for termite-resistant treatments for wood.

zoology↗

bioRxiv2023

Chewing Through Challenges: Exploring the Evolutionary Pathways to Wood-Feeding in Insects

Decaying wood, while an abundant and stable resource, presents considerable nutritional challenges due to its structural rigidity, chemical recalcitrance, and low nitrogen content. Despite these challenges, certain insect lineages have successfully evolved saproxylophagy (consuming and deriving sustenance from decaying wood), impacting nutrient recycling in ecosystems and carbon sequestration dynamics. This study explores the uneven phylogenetic distribution of saproxylophagy across insects and delves into the evolutionary origins of this trait in disparate insect orders. Employing a comprehensive analysis of gut microbiome data, encompassing both previously published datasets and newly generated data, from both saproxylophagous insects and their non-saproxylophagous relatives, this Hypothesis paper discusses the broader phylogenetic context and potential morphological, physiological, and symbiotic adaptations necessary for this dietary specialization. The study proposes the "Detritivore-First Hypothesis," suggesting an evolutionary pathway to saproxylophagy through detritivory, and highlights the critical role of symbiotic gut microbiomes in the digestion of decaying wood. The article aims to provide a deeper understanding of the macroevolutionary landscape and mechanisms underpinning the multiple origins and distribution of saproxylophagy in insects.

evolutionary biology↗

bioRxiv2023

A Mutation-driven oncofetal regression fuels phenotypic plasticity in colorectal cancer

Targeting cancer stem cells (CSCs) is crucial for effective cancer treatment1. However, the molecular mechanisms underlying resistance to LGR5+ CSCs depletion in colorectal cancer (CRC)2,3 remain largely elusive. Here, we unveil the existence of a primitive cell state dubbed the oncofetal (OnF) state, which works in tandem with the LGR5+ stem cells (SCs) to fuel tumor evolution in CRC. OnF cells emerge early during intestinal tumorigenesis and exhibit features of lineage plasticity. Normally suppressed by the Retinoid X Receptor (RXR) in mature SCs, the OnF program is triggered by genetic deletion of the gatekeeper APC. We demonstrate that diminished RXR activity unlocks an epigenetic circuity governed by the cooperative action of YAP and AP1, leading to OnF reprogramming. This high-plasticity state is inherently resistant to conventional chemotherapies and its adoption by LGR5+ CSCs enables them to enter a drug-tolerant state. Furthermore, through phenotypic tracing and ablation experiments, we uncover a functional redundancy between the OnF and stem cell (SC) states and show that targeting both cellular states is essential for sustained tumor regression in vivo. Collectively, these findings establish a mechanistic foundation for developing effective combination therapies with enduring impact on CRC treatment.

cancer biology↗

bioRxiv2023

Chloramphenicol reduces phage resistance evolution by suppressing bacterial cell surface mutants

Bacteriophages infect Gram-negative bacteria by attaching to molecules present on the bacterial outer membrane, often lipopolysaccharides (LPS). Modification of LPS can lead to resistance to phage infection. In addition, LPS modifications can impact antibiotic susceptibility, allowing for phage-antibiotic synergism. The evolutionary mechanism(s) behind such synergistic interactions remain largely unclear. Here, we show that the presence of antibiotics can affect the evolution of resistance to phage infection, using phage {Phi}X174 and Escherichia coli C. We use a collection of 34 E. coli C LPS strains, each of which is resistant to {Phi}X174, and has either a "rough" or "deep rough" LPS phenotype. Growth of the bacterial strains with the deep rough phenotype is inhibited at low concentrations of chloramphenicol (and, to a much lesser degree, gentamicin). Treating E. coli C wildtype with {Phi}X174 and chloramphenicol eliminates the emergence of mutants with the deep rough phenotype, and thereby slows the evolution of resistance to phage infection. At slightly lower chloramphenicol concentrations, phage resistance rates are similar to those observed at high concentrations; yet, we show that the diversity of possible mutants is much larger than at higher chloramphenicol concentrations. These data suggest that specific antibiotic concentrations can lead to synergistic phage-antibiotic interactions that disappear at higher antibiotic concentrations. Overall, we show that the change in survival of various {Phi}X174-resistant E. coli C mutants in the presence of antibiotics can explain the observed phage-antibiotic synergism. Classification: Biological Sciences, Evolution

evolutionary biology↗

bioRxiv2022

Oropouche orthobunyavirus infection is mediated by the cellular host factor Lrp1

Oropouche orthobunyavirus (OROV; Peribunyaviridae) is a mosquito-transmitted virus that causes widespread cases of human febrile illness in South America, with occasional progression to neurologic effects. Host entry factors mediating cellular entry of OROV are undefined. Here, we show that OROV requires the host protein low density lipoprotein-related protein 1 (Lrp1) for cellular infection. Cells from evolutionarily distinct species lacking Lrp1 were less permissive to OROV infection than cells with Lrp1. Treatment of cells with either the high-affinity Lrp1 ligand receptor-associated protein (RAP) or recombinant ectodomain truncations of Lrp1 significantly reduced OROV infection. Thus, Lrp1 is an important host factor required for infection of cells by OROV. Taken together with our results showing that Lrp1 is a newly identified receptor for Rift Valley fever virus (RVFV), Lrp1 may play a broader role in cellular infection by bunyaviruses than previously appreciated.

microbiology↗

bioRxiv2022

Congenital Rift Valley fever in Sprague Dawley rats is associated with diffuse infection and pathology of the placenta

Rift Valley fever (RVF) is a disease of animals and humans associated with abortions in ruminants and, more recently, late-gestation miscarriages in African women. Here, we use a rat model of congenital RVF to identify cellular tropism, pathology, and local immune responses occurring in the placenta during vertical transmission. Infection of pregnant rats during late gestation (embryonic day 14) resulted in vertical transmission to the placenta and widespread viral infection throughout the decidua, basal zone, and labyrinth zone. Some pups delivered from infected dams appeared normal while others had gross signs of teratogenicity including fetal death. Histopathological lesions were detected in placenta from pups regardless of teratogenicity, while teratogenic pups had more widespread hemorrhage throughout multiple placenta layers. Teratogenic events were also associated with significant increases in pro-inflammatory cytokines, type I interferons, and chemokines within the placental tissue. Thus, we found that RVFV displays a high degree of tropism for all placental tissue layers, and that the degree of hemorrhage and inflammatory mediator production is highest in placenta from pups with adverse outcomes. This is the first detailed pathological study of the mechanisms of RVFV infection of placental tissue in a tractable rodent model of congenital RVF disease.

microbiology↗

bioRxiv2021

NAD+ capping of RNA in Archaea and Mycobacteria

Chemical modifications of RNA affect essential properties of transcripts, such as their translation, localization and stability. 5-end RNA capping with the ubiquitous redox cofactor nicotinamide adenine dinucleotide (NAD+) has been discovered in organisms ranging from bacteria to mammals. However, the hypothesis that NAD+ capping might be universal in all domains of life has not been proven yet, as information on this RNA modification is missing for Archaea. Likewise, this RNA modification has not been studied in the clinically important Mycobacterium genus. Here, we demonstrate that NAD+ capping occurs in the archaeal and mycobacterial model organisms Methanosarcina barkeri and Mycobacterium smegmatis. Moreover, we identify the NAD+-capped transcripts in M. smegmatis, showing that this modification is more prevalent in stationary phase, and revealing that mycobacterial NAD+-capped transcripts include non-coding small RNAs, such as Ms1. Furthermore, we show that mycobacterial RNA polymerase incorporates NAD+ into RNA, and that the genes of NAD+-capped transcripts are preceded by promoter elements compatible with {sigma}A/{sigma}F dependent expression. Taken together, our findings demonstrate that NAD+ capping exists in the archaeal domain of life, suggesting that it is universal to all living organisms, and define the NAD+-capped RNA landscape in mycobacteria, providing a basis for its future exploration.

molecular biology↗

bioRxiv2020

HNRNPM controls circRNA biogenesis and splicing fidelity to sustain prostate cancer cell fitness

Cancer cells are differentially dependent on the splicing machinery compared to normal untransformed cells. The splicing machinery thus represents a potential therapeutic target in cancer. To identify splicing factors important for prostate cancer cell (PCa) cell growth, we performed a parallel pooled shRNA screen on in vitro passaged cells and in vivo xenografted PCa tumor lines. Our screen revealed HNRNPM as a potential regulator of PCa cell growth. RNA- and eCLIP-sequencing data suggest that HNRNPM is bound to transcripts of key homeostatic genes and that loss of HNRNPM binding in a subset of these genes results in aberrant exon inclusion and exon back-splicing events in target transcripts. In both linear and circular mis-spliced transcripts, HNRNPM appears to preferentially bind to GU-rich elements in long flanking proximal introns. Mimicry of HNRNPM dependent linear splicing events using splice-switching antisense oligonucleotides (SSOs) was sufficient to inhibit cell growth in HNRNPM expressing cells. This suggests that prostate cancer cell dependence on HNRNPM is likely a result of mis-splicing of key homeostatic coding and non-coding genes. Taken together, our data reveal a role for HNRNPM in supporting prostate cancer cell fitness, and also as a potential therapeutic target in PCa.

genomics↗

bioRxiv2020

Recovery of Consciousness and Cognition after General Anesthesia in Humans

Understanding how consciousness and cognitive function return after a major perturbation is important clinically and neurobiologically. To address this question, we conducted a three-center study of 30 healthy humans receiving general anesthesia at clinically relevant doses for three hours. We administered a pre- and post-anesthetic battery of neurocognitive tests, recorded continuous electroencephalography to assess cortical dynamics, and monitored sleep-wake activity before and following anesthetic exposure. We hypothesized that cognitive reconstitution would be a process that evolved over time in the following sequence: attention, complex scanning and tracking, working memory, and executive function. Contrary to our hypothesis, executive function returned first and electroencephalographic analyses revealed that frontal cortical dynamics recovered faster than posterior cortical dynamics. Furthermore, actigraphy indicated normal sleep-wake patterns in the post-anesthetic period. These recovery patterns of higher cognitive function and arousal states suggest that the healthy human brain is resilient to the effects of deep general anesthesia.

neuroscience↗

bioRxiv2019

Mind the Outgroup: Influence of Taxon Sampling on Total-Evidence Dating of Pimpliform Parasitoid Wasps (Hymenoptera, Ichneumonidae)

Taxon sampling is a central aspect of phylogenetic study design, but it has received limited attention in the context of molecular dating and especially in the framework of total-evidence dating, a widely used dating approach that directly integrates molecular and morphological information from extant and fossil taxa. We here assess the impact of different outgroup sampling schemes on age estimates in a total-evidence dating analysis under the uniform tree prior. Our study group are Pimpliformes, a highly diverse, rapidly radiating group of parasitoid wasps of the family Ichneumonidae. We cover 201 extant and 79 fossil taxa, including the oldest fossils of the family from the Early Cretaceous and the first unequivocal representatives of extant subfamilies from the mid Paleogene. Based on newly compiled molecular data from ten nuclear genes and a morphological matrix that includes 222 characters, we show that age estimates become both older and less precise with the inclusion of more distant and more poorly sampled outgroups. In addition, we discover an artefact that might be detrimental for total-evidence dating: "bare-branch attraction", namely high attachment probabilities of, especially, older fossils to terminal branches for which morphological data are missing. After restricting outgroup sampling and adding morphological data for the previously attracting, bare branches, we recover a Middle and Early Jurassic origin for Pimpliformes and Ichneumonidae, respectively. This first age estimate for the group not only suggests an older origin than previously thought, but also that diversification of the crown group happened before the Cretaceous-Paleogene boundary. Our case study demonstrates that in order to obtain robust age estimates, total-evidence dating studies need to be based on a thorough and balanced sampling of both extant and fossil taxa, with the aim of minimizing evolutionary rate heterogeneity and missing morphological information.

zoology↗