Biology subjects

Larson, T. A.

Publications and source records attributed to Larson, T. A..

3 recordsLinked to original sources

bioRxiv2026

ARTIFICIAL SELECTION DIVERSIFIES BIRDSONG THROUGH POLYGENIC CHANGES ACROSS SENSORY AND MOTOR SYSTEMS

Vocal learning, or the ability to acquire and produce contextualized sounds through social interaction, underlies human speech yet has evolved in a few animal lineages, including songbirds. In songbirds, learned song is produced by a dedicated neural circuit and depends on auditory feedback for its acquisition and maintenance. Roughly four centuries of artificial selection on the domestic canary (Serinus canaria) have produced song breeds whose vocalizations diverge as much as those of distinct species, offering a rare intraspecific system in which to identify the genetic and neural changes underlying vocal divergence. Here we show that selection for song reshaped the canary song control system. Compared with breeds selected for plumage or body form, song breeds show increased neural progenitor proliferation and breed-specific changes in neuronal recruitment, sensorimotor brain region volume, and auditory sensitivity. Genome-wide analyses reveal a polygenic architecture underlying song divergence, enriched for transcriptional regulation and synaptic transmission genes. Among these, we find a coding variant in ADGRV1, the gene mutated in human Usher syndrome type 2C, associated with low-frequency singing and elevated auditory thresholds in canary. Disrupting ADGRV1 in zebrafish alters hair cell dynamics, linking adgrv1 mutation to a peripheral sensory mechanism. These findings demonstrate that learned vocal behavior can diversify rapidly through changes spanning sensory, neurogenic, and motor systems, with hearing itself as a substrate for selection.

evolutionary biology↗

bioRxiv2026

Precursor Cells in the Parenchyma Act in Concert with Ventricular Neural Progenitors to Facilitate Dramatic Astrocyte Turnover and Recovery Following Natural Neuronal Death

Seasonal environmental variation represents one of the most pervasive and recurring forces shaping the vertebrate brain through cycles of neural circuit plasticity and remodeling that ultimately serves to maintain adaptive behavior. Although the contribution of adult neurogenesis to such remodeling is well-characterized across vertebrates, the role of astrocytes in supporting or enabling this process remains almost entirely unknown. Here, using the robust and natural seasonal loss of neurons within the sensorimotor nucleus HVC of the songbird, we identify a rapid astrocytic turnover event following neuronal loss and reveal a previously undescribed cellular mechanism supporting neural circuit recovery. Using lineage-specific and proliferation labeling, we establish the presence of a previously undescribed SOX2-positive neural progenitor-like population residing within the vertebrate parenchyma, outside the canonical ventricular zone niche. These parenchymal astrocyte precursor cells (pAPCs) maintain quantifiable, steady-state proliferation under homeostatic conditions, yet expand in pool size following seasonally-driven neuronal loss. The coordinated response of canonical neural progenitor cells and pAPCs produces new astrocytes that persist throughout the re-establishment of homeostasis. These findings reveal extensive astrocyte plasticity in the adult vertebrate brain, operating across both canonical and non-canonical progenitor niches, and challenge the prevailing view that parenchymal astrocytes are largely post-mitotic outside of injury contexts. More broadly, our findings establish a framework for understanding how glial populations contribute to neural circuit resilience both to the physiological and neural changes that recurring seasonal transitions drive, and to the accelerating environmental changes that increasingly challenge the adaptive capacity of animal brains worldwide.

neuroscience↗

bioRxiv2019

Fate plasticity and reprogramming in genetically distinct populations of Danio leucophores

Understanding genetic and cellular bases of adult form remains a fundamental goal at the intersection of developmental and evolutionary biology. The skin pigment cells of vertebrates, derived from embryonic neural crest, are a useful system for elucidating mechanisms of fate specification, pattern formation, and how particular phenotypes impact organismal behavior and ecology. In a survey of Danio fishes, including zebrafish Danio rerio, we identified two populations of white pigment cells--leucophores--one of which arises by transdifferentiation of adult melanophores and another that develops from a yellow/orange xanthophore-like progenitor. Single-cell transcriptomic, mutational, chemical and ultrastructural analyses of zebrafish leucophores revealed cell-type specific chemical compositions, organelle configurations and genetic requirements. At the organismal level, we identified distinct physiological responses of leucophores during environmental background matching and we show that leucophore complement influences behavior. Together, our studies revealed new, independently arisen pigment cell types and mechanisms of fate acquisition in zebrafish, and illustrate how concerted analyses across hierarchical levels can provide insights into phenotypes and their evolution.

developmental biology↗