Choi, W.-Y. | bioRxiv Science

bioRxiv2026

Sperm length ornamentation associates with survival and sterility after heatwaves among Drosophila species

Whether sexual selection facilitates or hinders adaptation to novel environments is a question of fundamental importance due to current rapid environmental change. Using phylogenetic comparative analysis in 42 Drosophila species, we found that sperm length - a sexually selected ornament - positively associates with the ability of males to survive high temperatures. However, the ability to remain fertile does not increase with sperm length to the same extent, meaning that longer sperm species experience a larger gap between temperatures that kill and temperatures that sterilize males. The findings are consistent with the idea that strong sexual selection on condition-dependent exaggerated traits may facilitate somatic resilience to environmental stressors, but that susceptibility to heat-induced infertility may be a cost of extreme sperm ornamentation. Overall, the data suggests multifaceted links between postcopulatory sexual selection and climate change.

evolutionary biology↗

bioRxiv2026

Cancer stem cell transcriptomic signatures reveal patient-to-patient heterogeneity emphasizing the need for patient-specific ovarian cancer targets

Background/Objectives: In high-grade serous ovarian cancer (HGSOC), the abilities of tumor cells to resist cytotoxic treatment and relapse are largely driven by ovarian cancer stem cells (CSCs). CSCs are a population of cells within a tumor that maintain stem-like qualities and have the capacity to produce metastasis and drive drug resistance. Based on the complexity of CSC signaling and emerging evidence of differential isoform usage in development, we hypothesize that CSCs possess a patient-specific, heterogeneous landscape which exploits isoform diversity to sustain stemness, metastasis and drug resistance. Methods: RNA-seq was generated from 3 patient-derived HGSOC (PD-HGSOC) to investigate stemness and differentiation status comparing standard culture and CSCs. The data was analyzed at both gene- and isoform-levels to identify patient-specific CSC features and define mechanisms of cancer-related stemness and plasticity. Results: CSCs exhibited higher stemness characteristics and identified differentially expressed gene sets across PD-HGSOCs. We noted that each patient had a distinct subset of genes regulating stemness phenotypes which suggested multiple mechanisms of CSC development and maintenance. Additionally, a large proportion of gene-level expression changes were driven by the differential expression of a single predominant isoform. Importantly, our isoform-level analysis enabled the identification of differential isoform usage that would not be detected with gene level expression analysis. Conclusions: CSC phenotypes such as chemoresistance, metastasis and self-renewal are conserved across patients, but arise from largely patient-specific gene and isoform programs. This CSC heterogeneity is reflective of the heterogeneity seen in patients and should be further evaluated in deriving precision-medicine approaches for HGSOC.

cancer biology↗