Sami Farhi, Head of Multiomics and Functional Genomics, Broad Clinical Lab This talk explores how spatial transcriptomics is used to study mini-puberty in human testes, revealing new insights into developmental biology and cell-to-cell interactions. Mini-puberty is a critical developmental window that influences long-term reproductive health but many of the underlying cellular and molecular mechanisms remain poorly understood. In this presentation from AGBT 2026, Sami Farhi, Broad Clinical Lab, demonstrates how spatial transcriptomics can be applied to study developmental biology at unprecedented resolution. Building on foundational resources like the GTEx project, this work integrates spatial data across multiple developmental time points to better understand how tissues evolve over time. Using human testes samples spanning early infancy through adolescence, the study reveals key biological insights, including: • The role of hormone signaling during mini-puberty • Dynamic interactions between Leydig and Sertoli cells • Spatially resolved gene expression patterns driving tissue maturation • Previously unreported expansion of endothelial cells following mini-puberty • Evidence linking early Sertoli cell development to adult sperm production By combining high-plex molecular measurements with spatial context, this work showcases how emerging spatial technologies can uncover complex developmental processes within a single tissue sample. As datasets grow larger and multi-timepoint studies become more feasible, approaches like this are poised to transform our understanding of human development, disease biology, and cellular interactions. Subscribe to the Illumina video channel http://www.youtube.com/subscription_center?add_user=IlluminaInc A global genomics leader, Illumina provides comprehensive next-generation sequencing solutions to the research, clinical, and applied markets. Through collaborative innovation, Illumina is fueling groundbreaking advancements in oncology, reproductive health, genetic disease, microbiology, agriculture, forensic science, and beyond. View customer spotlight videos https://www.youtube.com/playlist?list=PLKRu7cmBQlajfheLzgbI4S7xBn7IDbt79 View Illumina webinars https://www.youtube.com/playlist?list=PLKRu7cmBQlahpXlnrrXlQw9itVJ8yHwUZ View Illumina support videos https://www.youtube.com/playlist?list=PLKRu7cmBQlajbm2KGsICWb-JOnusJfYvM LinkedIn: https://www.linkedin.com/company/illumina X: https://x.com/illumina Instagram: https://www.instagram.com/illuminainc/ Facebook: https://www.facebook.com/illuminainc TikTok: https://www.tiktok.com/@illuminainc #illumina #Spatial #StrataMapSpatial #BroadInstitute #SamiFarhi 00:00 Introduction & Study Overview 00:25 Background: GTEx and Developmental Atlases 01:41 Why Spatial Biology Matters in Development 02:13 Testes Development Explained 02:58 Mini-Puberty: Hormonal Dynamics 05:12 Spatial Transcriptomics Workflow 06:00 Multi-timepoint Dataset Overview 07:00 Key Discovery: Endothelial Expansion 07:26 Leydig Cell Signaling Analysis 08:34 Sertoli Cell Maturation Findings 08:59 Power of Spatial + Temporal Analysis