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Many natural motor skills, such as speaking or locomotion, are acquired through a process of trial-and-error learning over the course of development. It has long been hypothesized, motivated by observations in artificial learning experiments, that dopamine has a crucial role in this process. Dopamine in the basal ganglia is thought to guide reward-based trial-and-error learning by encoding reward prediction errors¹, decreasing after worse-than-predicted reward outcomes and increasing after better-than-predicted ones. Our previous work in adult zebra finches—in which we changed the perceived song quality with distorted auditory feedback—showed that dopamine in Area X, the singing-related basal ganglia, encodes performance prediction error: dopamine is suppressed after worse-than-predicted (distorted syllables) and activated after better-than-predicted (undistorted syllables) performance². However, it remains unknown whether the learning of natural behaviours, such as developmental vocal learning, occurs through dopamine-based reinforcement. Here we tracked song learning trajectories in juvenile zebra finches and used fibre photometry³ to monitor concurrent dopamine activity in Area X. We found that dopamine was activated after syllable renditions that were closer to the eventual adult version of the song, compared with recent renditions, and suppressed after renditions that were further away. Furthermore, the relationship between dopamine and song fluctuations revealed that dopamine predicted the future evolution of song, suggesting that dopamine drives behaviour. Finally, dopamine activity was explained by the contrast between the quality of the current rendition and the recent history of renditions—consistent with dopamine’s hypothesized role in encoding prediction errors in an actor–critic reinforcement-learning model^4,5. Reinforcement-learning algorithms⁶ have emerged as a powerful class of model to explain learning in reward-based laboratory tasks, as well as for driving autonomous learning in artificial intelligence⁷. Our results suggest that complex natural behaviours in biological systems can also be acquired through dopamine-mediated reinforcement learning.

Comparative genomic studies can identify genes under evolutionary constraint or specialized for trait innovation. Growing evidence suggests that evolutionary constraint also acts on non-coding regulatory sequences, exerting significant impacts on fitness-related traits, although it has yet to be thoroughly explored in plants. Using the assay for transposase-accessible chromatin by sequencing (ATAC-seq), we profile over 80,000 maize accessible chromatin regions (ACRs), revealing that ACRs evolve faster than coding genes, with about one-third being maize-specific and regulating genes associated with speciation. We highlight the role of transposable elements (TEs) in driving intraspecific innovation of ACRs and identify hundreds of candidate ACRs potentially involved in transcriptional rewiring during maize domestication. Additionally, we demonstrate the importance of accessible chromatin in maintaining subgenome dominance and controlling complex trait variations. This study establishes a framework for analyzing the evolutionary trajectory of plant regulatory sequences and offers candidate loci for downstream exploration and application in maize breeding.

Predicting and quantifying phenotypic consequences of genetic variants in rare disorders is a major challenge, particularly pertinent for ‘actionable’ genes such as thyroid hormone transporter MCT8 (encoded by the X-linked SLC16A2 gene), where loss-of-function (LoF) variants cause a rare neurodevelopmental and (treatable) metabolic disorder in males. The combination of deep phenotyping data with functional and computational tests and with outcomes in population cohorts, enabled us to: (i) identify the genetic aetiology of divergent clinical phenotypes of MCT8 deficiency with genotype-phenotype relationships present across survival and 24 out of 32 disease features; (ii) demonstrate a mild phenocopy in ~400,000 individuals with common genetic variants in MCT8; (iii) assess therapeutic effectiveness, which did not differ among LoF-categories; (iv) advance structural insights in normal and mutated MCT8 by delineating seven critical functional domains; (v) create a pathogenicity-severity MCT8 variant classifier that accurately predicted pathogenicity (AUC:0.91) and severity (AUC:0.86) for 8151 variants. Our information-dense mapping provides a generalizable approach to advance multiple dimensions of rare genetic disorders.

Oil-based drilling cutting residues (OBDCRs) are among the primary solid wastes generated during shale gas exploration and development. Utilizing existing equipment to transform OBDCRs into ceramsites appears to be a feasible and resource-efficient approach. In this study, building ceramsites were prepared with OBDCRs incorporating with fly ash (a byproduct of coal combustion) as raw materials. The aim was to comprehensively and systematically investigate physicochemical properties and characteristics of heavy metals (HMs) in the ceramsites. Research shows that building ceramsites can indeed be prepared using OBDCRs, which exhibit good comprehensive properties and strong resistance to acid/ alkali. The main HMs found in ceramsite are barium (Ba), chromium (Cr), nickel (Ni), lead (Pb), arsenic (As), cadmium (Cd), and mercury (Hg). During the calcination process, these OBDCRs, along with fly ash and foaming agent, underwent mutual melting, resulting in the formation of glass, anorthite and mullite. These newly formed phases effectively encapsulated HMs, resulting in varying degrees of enrichment of HMs such as As, Ba, Pb, Cr, and Ni, except for Cd and Hg. However, the leaching toxicity of these HMs in the ceramsite was significantly lower compared to that of the original OBDCRs. Further analysis revealed a significant increase in the proportion of Fe-Mn Oxides and Organic Matter in HMs such as Cr, Ni, As, Cd, and Pb, while the proportion of Exchangeable and Carbonates forms decreased markedly. This trend clearly demonstrated that the calcination process modified the physical and chemical properties of the ceramsite, and effectively stabilized HMs, i.e., migrated from an active state to a more stable form.

Bioactive antimicrobial films play important roles in various fields, such as biodegradable interfaces, tissue regeneration, and biomedical applications where preventing infection, biocompatibility, and immune rejection are important. In the present study, bioactive POSS-doped Ti₃C₂T_x MXene filled PLA composite film was prepared using the solution casting method for biomedical applications. The contact angle tests were investigated to reveal the usability of the thin films in biomedical applications. The angle decreased from 85.92° degrees in pure PLA thin films to 72.23° on POSS-doped Ti₃C₂T_x MXene films. The antibacterial performance, cytotoxicity and cell viability assessments of the prepared films have also been thoroughly investigated. Antibacterial tests revealed that the POSS-doped Ti₃C₂T_x MXene films effectively inhibited the growth of E. coli and S. aureus by 65.93% and 80.63%, respectively, within 4 h. These inhibition rates were observed as 58.32% and 54.97% for E. coli and S. aureus, respectively, after 24 h. Cytotoxicity assessments demonstrated that PMPs consistently showed higher cell viability due to the combination of POSS and Ti₃C₂T_x MXene. The obtained results suggest that the POSS-doped Ti₃C₂T_x MXene film is a promising candidate in cases where bacterial inhibition and high biocompatibility are of critical importance.