Biology subjects

Capobianco, A.

Publications and source records attributed to Capobianco, A..

5 recordsLinked to original sources

bioRxiv2026

Macroevolutionary consequences of twin neck innovations in deep-sea dragonfishes

The origin of novel phenotypes can influence access to new ecological resources, which may have positive, neutral, or negative effects on subsequent phenotypic diversification. In this study, we tested the macroevolutionary consequences of a pair of putative functional innovations occurring in deep-sea fishes of the order Stomiiformes. Integrating phylogenetic comparative methods, micro-CT scans, and external body measurements, we recover a mosaic of diversification trends associated with these innovations. We found some evidence for elevated evolutionary rates in tooth morphology associated with the predatory dragonfishes, which possess a gap between their vertebral column and skull that exposes the notochord and enables neck-like flexibility. However, a second novelty building upon the first, a functional neck joint enabling extreme cranial kinesis, was linked to faster rates of skull evolution. Our results suggest that innovations that help shift ecological roles and overcome functional constraints related to those roles, like gape-limitation in prey depauperate habitats, may play an important role in promoting phenotypic diversification. This work builds on a growing body of evidence highlighting how the deep sea promotes phenotypic diversity, generating the extreme forms that are celebrated by scientists and the public alike.

evolutionary biology↗

bioRxiv2025

How many characters are needed to reconstruct a phylogeny?

Despite increased recent attention towards Bayesian phylogenetics and its applications in understanding macroevolutionary processes, it remains unclear how many discrete characters are needed to accurately estimate tree topologies in a Bayesian framework. This could be particularly relevant for morphological datasets used in phylogenetics, as they usually consist of few dozens to few hundreds of characters--orders of magnitude smaller than most molecular datasets. I designed a simulation study in the software RevBayes to explore how the number of sampled discrete characters affects accuracy and precision of Bayesian phylogenetic estimates, under various setups differing in number of taxa, average number of state changes per character (i.e., tree length), and number of states per character. Results indicate that between 100 and 500 variable characters are necessary to reach sufficient accuracy and precision of phylogenetic estimates for as low as 20 tips. All other parameters being equal, multistate characters produce slightly more accurate estimates than binary characters, and more labile characters produce more accurate estimates for trees above 50 tips. The results of this study highlight the continuous need for global research efforts geared towards the characterization and digitization of interspecific morphological diversity in both extant and extinct taxa.

evolutionary biology↗

bioRxiv2025

Neutrophil Reprogramming Underlie Vasculopathy and Lung Disease in Systemic Sclerosis

The role of neutrophils in systemic sclerosis (SSc) remains incompletely understood. To address this, blood samples from 39 SSc patients, 39 healthy controls, and 22 systemic lupus erythematosus (SLE) patients were analyzed. In SSc, neutrophils exhibited substantial activation, evidenced by granule mobilization, elevated plasma levels of Neutrophil Extracellular Trap (NET) byproducts, and upregulated TIE2 expression. In parallel, they underwent metabolic reprogramming, characterized by increased autophagy, likely to support the heightened energy demands of activation. By contrast, neutrophils from SLE patients displayed minimal autophagy, lacked TIE2 expression, and shifted toward low-density granulocytes. Neutrophil reprogramming in SSc correlated with plasma levels of HMGB1+ EVs. Mechanistically, EVs purified from the plasma of patients with SSc adhered to neutrophils when injected in immunodeficient NSG mice, inducing autophagy, TIE2 expression, and promoting lung inflammation and fibrosis. These effects were abrogated by HMGB1 inhibitors and required the HMGB1 receptor, RAGE. Recombinant HMGB1 recapitulated EV-induced effects, while neutrophil targeting by liposome-encapsulated clodronate prevented them. In summary, neutrophils in SSc exhibit a dual phenotype of autophagy and activation driven by HMGB1+ EVs, representing a pathogenic mechanism and a potential therapeutic target in SSc. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=139 HEIGHT=200 SRC="FIGDIR/small/637866v1_ufig1.gif" ALT="Figure 1"> View larger version (54K): org.highwire.dtl.DTLVardef@dbf3dcorg.highwire.dtl.DTLVardef@67243forg.highwire.dtl.DTLVardef@17cb6c4org.highwire.dtl.DTLVardef@c3370a_HPS_FORMAT_FIGEXP M_FIG C_FIG

immunology↗

bioRxiv2024

On the Mkv Model with Among-Character Rate Variation

Models used in likelihood-based morphological phylogenetics often adapt molecular phylogenetics models to the specificities of morphological data. Such is the case for the widely used Mkv model-- which introduces an acquisition bias correction for sampling only characters that are observed to be variable--and for models of among-character rate variation (ACRV), routinely applied by researchers to relax the equal-rates assumption of Mkv. However, the interaction between variable character acquisition bias and ACRV has never been explored before. We demonstrate that there are two distinct approaches to condition the likelihood on variable characters when there is ACRV, and we call them joint and marginal acquisition bias. Far from being just a trivial mathematical detail, we show that the way in which the variable character conditional likelihood is calculated results in different assumptions about how rate variation is distributed in morphological datasets. Simulations demonstrate that tree length and amount of ACRV in the data are systematically biased when conditioning on variable characters differently from how the data was simulated. Moreover, an empirical case study with extant and extinct taxa reveals a potential impact not only on the estimation of branch lengths, but also of phylogenetic relationships. We recommend the use of the marginal acquisition bias approach for morphological datasets modeled with ACRV. Finally, we urge developers of phylogenetic software to clarify which acquisition bias correction is implemented for both estimation and simulation, and we discuss the implications of our findings on modeling variable characters for the future of morphological phylogenetics.

evolutionary biology↗

bioRxiv2024

A 20+ Ma old enamel proteome from Canada's High Arctic reveals diversification of Rhinocerotidae in the middle Eocene-Oligocene

In the past decade, ancient protein sequences have emerged as a valuable source of data for deep-time phylogenetic inference. Still, the recovery of protein sequences providing novel phylogenetic insights does not exceed 3.7 Ma (Pliocene). Here, we push this boundary back to 21-24 Ma (early Miocene), by retrieving enamel protein sequences of an early-diverging rhinocerotid (Epiaceratherium sp. - CMNF-59632) from the Canadian High Arctic. We recover partial sequences of seven enamel proteins (AHSG, ALB, AMBN, AMELX, AMTN, ENAM, MMP20) and over 1000 peptide-spectrum matches, spanning over at least 251 amino acids. Authentic endogeneity of these sequences is supported by indicators of protein damage, including several spontaneous and irreversible post-translational modifications accumulated during prolonged diagenesis and reaching near-complete occupancy at many sites. Bayesian tip-dating, across 15 extant and extinct perissodactyl taxa, places the divergence time of CMNF-59632 in the middle Eocene-Oligocene, and identifies a later divergence time for Elasmotheriinae in the Oligocene. The finding weakens alternative models suggesting a deep basal split between Elasmotheriinae and Rhinocerotinae. This divergence time of CMNF-59632 coincides with a phase of high diversification of rhinocerotids, and supports a Eurasian origin of this clade in the late Eocene or Oligocene. The findings are consistent with previous hypotheses on the origin of the enigmatic fauna of the Haughton crater, which, in spite of their considerable degree of endemism, also display similarity to distant Eurasian faunas. Our findings demonstrate the potential of palaeoproteomics in obtaining phylogenetic information from a specimen that is ten times older than any sample from which endogenous DNA has been obtained.

paleontology↗