# IRIS

Each signaling pathway leaves a consistent fingerprint of gene activity across cell types, so signaling history no longer has to be reconstructed separately for every cell type. IRIS is a neural-network model that reads a cell's overall gene activity and estimates which pathways were switched on at each developmental stage. Tested on single cells from mouse embryos during gastrulation, it predicted when and where pathways activate in heart, gut, muscle and spinal cord lineages, and its prediction for a lung-development cell type was confirmed in mouse embryo experiments.

Each signaling pathway leaves a consistent fingerprint of gene activity across cell types, so signaling history no longer has to be reconstructed separately for every cell type. IRIS is a neural-network model that reads a cell's overall gene activity and estimates which pathways were switched on at each developmental stage. Tested on single cells from mouse embryos during gastrulation, it predicted when and where pathways activate in heart, gut, muscle and spinal cord lineages, and its prediction for a lung-development cell type was confirmed in mouse embryo experiments.

The authors pretrain Iris-3B, a 3B-parameter pixel-space text-to-image transformer trained from scratch through a 256→512→1024 curriculum with v-prediction and DINOv2 REPA, and convert the latent FLUX.2 Klein base 4B to pixel space; after fine-tuning both pixel backbones for monocular depth and image restoration, they find no significant improvement from a pixel-space generative prior: on depth Iris-3B is level with latent FLUX.2 Klein while the converted model trails it, and on DIV2K restoration neither pixel model beats a latent FLUX.2 Klein fine-tune.

The authors pretrain Iris-3B, a 3B-parameter pixel-space text-to-image transformer trained from scratch through a 256→512→1024 curriculum with v-prediction and DINOv2 REPA, and convert the latent FLUX.2 Klein base 4B to pixel space; after fine-tuning both pixel backbones for monocular depth and image restoration, they find no significant improvement from a pixel-space generative prior: on depth Iris-3B is level with latent FLUX.2 Klein while the converted model trails it, and on DIV2K restoration neither pixel model beats a latent FLUX.2 Klein fine-tune.