Mendez, J. M. | bioRxiv Science

bioRxiv2026

Automated inference of respiratory and syringeal biomechanical trajectories from birdsong acoustics

Songbirds, in particular zebra finches (Taeniopygia guttata), provide a powerful model for investigating the neural mechanisms of learned vocal behavior. Researchers typically rely on the acoustic structure of birdsong to quantify vocal behavior. As a more direct measure of motor control, we present VIBE: Vocal acoustic Inversion to Biomechanical Estimates, an open-source pipeline that recovers the biomechanical control parameters of song production directly from the acoustic waveform. Biomechanical models of the songbird syrinx describe vocal production with two continuously varying parameters: and {beta}, representing subsyringeal air sac pressure and syringeal muscle tension, respectively. Recovering these parameters from song acoustics provides a motor-based coordinate system against which neural activity or other dependent variables can be directly compared. Because and {beta} are the coupled control parameters of a nonlinear oscillator, their joint recovery is non-trivial. VIBE addresses this through iterative optimization of the governing normal-form equations. We validate VIBE against recorded air sac pressure across 44 songs from twelve birds, showing that the recovered corresponds to empirically measured air sac pressure. Pairing VIBE with Neuropixels recordings from RA in five birds, we find that RA activity is well predicted by the recovered parameters, and that and {beta} add predictive power beyond the acoustic features of song. By recovering biomechanical control parameters from the acoustic signal, VIBE makes the biomechanical coordinate system of song production accessible to the broader songbird research community. New & NoteworthyVIBE provides a novel, fully automated pipeline to recover the biomechanical control parameters of the avian vocal organ, and {beta}, as continuously varying quantities from the raw acoustic waveform, making the full biomechanical model of song production accessible at the scale of modern datasets.

neuroscience↗

bioRxiv2024

Differential Conservation and Loss of CR1 Retrotransposons in Squamates Reveals Lineage-Specific Genome Dynamics across Reptiles

Transposable elements (TEs) are repetitive DNA sequences which create mutations and generate genetic diversity across the tree of life. In amniotic vertebrates, TEs have been mainly studied in mammals and birds, whose genomes generally display low TE diversity. Squamates (Order Squamata; [~]11,000 extant species of lizards and snakes) show as much variation in TE abundance and activity as they do in species and phenotypes. Despite this high TE activity, squamate genomes are remarkably uniform in size. We hypothesize that novel, lineage-specific dynamics have evolved over the course of squamate evolution to constrain genome size across the order. Thus, squamates may represent a prime model for investigations into TE diversity and evolution. To understand the interplay between TEs and host genomes, we analyzed the evolutionary history of the CR1 retrotransposon, a TE family found in most tetrapod genomes. We compared 113 squamate genomes to the genomes of turtles, crocodilians, and birds, and used ancestral state reconstruction to identify shifts in the rate of CR1 copy number evolution across reptiles. We analyzed the repeat landscapes of CR1 in squamate genomes and determined that shifts in the rate of CR1 copy number evolution are associated with lineage-specific variation in CR1 activity. We then used phylogenetic reconstruction of CR1 subfamilies across amniotes to reveal both recent and ancient CR1 subclades across the squamate tree of life. The patterns of CR1 evolution in squamates contrast other amniotes, suggesting key differences in how TEs interact with different host genomes and at different points across evolutionary history.

genomics↗