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O'Neill, R. S.

Publications and source records attributed to O'Neill, R. S..

3 recordsLinked to original sources

Autobehaver: An AI-Based Pipeline for Animal Behavior Analysis

Behavior arises from the complex interplay between an organisms nervous system, its genetic makeup, and the environment. High-resolution, high-throughput behavioral quantification is essential for dissecting biological function and the effects of genetic perturbation, but automated analysis remains challenging. Here, we present Autobehaver, an automated behavioral analysis pipeline based on a low-cost, high-throughput recording platform that captures videos of individual Drosophila. From each video, we extracted keypoints and used a custom Transformer to assign frame-wise behavior and orientation labels. We then converted these predictions into high-dimensional per-animal feature vectors and trained XGBoost ensembles to classify animals and identify the features that separated groups. By applying SHAP analysis to the classifier ensemble, we identified the behavioral features most informative for distinguishing groups of flies. We demonstrated the approach in several ways. First, we recovered known behavioral changes associated with heat-activated dTrpA1 activity in specific neural circuits. Second, we detected age-associated behavioral changes consistent with gradual impairment of locomotor and climbing ability. Finally, we used Autobehavers classifier ensemble to place animals with intermediate phenotypes along a behavioral axis and used feature-importance analysis to reveal the behavioral features underlying those intermediate states. Together, Autobehaver provides an interpretable framework for quantitative behavioral phenotyping and comparative analysis of complex genotypes.

animal behavior and cognition↗

Spd-2 Gene Duplication Suggests Cell-Type Specific Assembly Mechanisms of Pericentriolar Material

Centrosomes are multi-protein complexes that function as the major microtubule organizing center (MTOC) for the cell. While centrosomes play tissue-specific MTOC functions, little is known about how particular centrosome proteins are regulated across cell types to achieve these different functions. To investigate this cell type-specific diversity, we searched for gene duplications of centrosome genes in the Drosophila lineage with the aim of identifying centrosome gene duplications where each copy evolved for specialized functions. Through in depth functional analysis of a Spd-2 gene duplication in the Willistoni group, we discovered differences in the regulation of PCM in somatic and male germline cells. The parental gene, Spd-2A, is expressed in somatic cells, where it can function to organize pericentriolar material (PCM) and the mitotic spindle in larval brain neuroblasts. Spd-2A is absent during male meiosis, and even when ectopically expressed in spermatocytes it fails to rescue PCM and spindle organization. In contrast, the new gene duplicate, Spd-2B, is expressed specifically in spermatocytes. During male meiosis, Spd-2B localizes to centrosomes, organizes PCM and spindles, and is sufficient for proper male fertility. Experiments using chimeric transgenes reveal that differences in the C-terminal tails of Spd-2A and Spd-2B are responsible for these functional changes. Thus, Spd-2A and Spd-2B have evolved complementary functions by specializing for distinct subsets of cells. Together, our results demonstrate that somatic cells and male germline cells have fundamentally different requirements for PCM, suggesting that PCM proteins such as Spd-2 is differentially regulated across cell types to satisfy distinct requirements. HighlightsO_LISpd-2 gene duplication in the Willistoni group is rapidly evolving C_LIO_LIParent gene Spd-2A is expressed in somatic cells, whereas the gene duplicate Spd-2B is expressed in spermatocytes C_LIO_LISpd-2A organizes pericentriolar material during somatic cell mitosis C_LIO_LISpd-2B is specialized for pericentriolar material organization during male meiosis C_LI

cell biology↗

Traip Mitotic Function Controls Brain Size

Microcephaly is a developmental failure to achieve proper brain size and neuron number. Mutations in diverse genes are linked to microcephaly, including several with DNA damage repair (DDR) functions; however, it is not well understood how these DDR gene mutations limit brain size. One such gene is TRAIP, which has multiple known functions in DDR. We characterized the Drosophila ortholog Traip, finding that loss of Traip causes a brain-specific defect in the Mushroom Body (MB). Traip mutant (traip-) MBs had reduced size and fewer neurons, but no neurodegeneration, consistent with human primary microcephaly disorders. Reduced neuron numbers in traip- were explained by premature caspase-dependent cell death of MB neuroblasts (MB-NBs). Many traip- MB-NBs had prominent chromosome bridges in anaphase, along with polyploidy, aneuploidy, or micronuclei. We found no evidence for an interphase DNA repair role for Traip in MB-NBs; instead, proper MB development requires Traip function during mitosis, where Traip localizes to centrosomes and mitotic spindles. Our results suggest that proper brain size is ensured by the recently described role for TRAIP in unloading stalled replication forks in mitosis, which suppresses DNA bridges and neural stem cell death to promote proper neuron number. Further, the mitotic nature of traip- MB-NB defects and Traip localization suggest a closer etiological link between DDR microcephaly genes like Traip and the centrosome/spindle-related genes more commonly associated with microcephaly.

developmental biology↗