Review papers with raw data transparency

Key evidentiary claims (each claim linked to the review)

• Yolk‑sac embryonic origin and conserved ontogeny across vertebrates (mice, humans, chicken, zebrafish) — supported by fate-mapping, lineage tracing, and developmental transcriptomics Yolk‑sac origin & fate‑mapping
• Core transcriptional regulators PU.1 (SPI1) and IRF8 are conserved and necessary for microglial specification across vertebrates PU.1/IRF8 axis
• Environmental niche signals (CSF1R + ligands CSF1/IL‑34; TGF‑β) are essential for survival and homeostatic identity; CSF1R requirement is conserved across vertebrates CSF1R/IL‑34/TGF‑β niche
• Conserved core signature genes (P2RY12, TMEM119, HEXB, SALL1, CX3CR1) yet clear cross‑species expression differences (humans/macaques closer than rodents) — important for model selection Core markers & species differences
• Disease-associated microglial (DAM) programs (lipid handling, phagocytosis, antigen presentation) have conserved elements, but species differences in inflammatory and antigen-presentation responses are prominent — caution for direct translation from mouse AD models to humans DAM conservation & divergence

Critical strengths

• Comprehensive, multi-modal synthesis (lineage tracing, scRNA‑seq, imaging) integrating many vertebrate taxa, reducing single-model bias Comprehensive methods synthesis
• Explicit discussion of translatability limits (SPF housing, model acceleration, lifespan differences) and proposals (wildling models, xenotransplants) to mitigate them Translatability discussion

Key limitations, blind spots, and cautions

• Review synthesizes heterogeneous primary methodologies — differences in single‑cell platforms, tissue processing, and lab environments can produce artifacts; authors acknowledge this but harmonization remains challenging Method heterogeneity caveat
• Incomplete coverage of some taxa (e.g., reptiles, many marsupials) and limited raw data availability in a few referenced studies — reduces breadth of evolutionary claims beyond cited vertebrates Taxonomic data gaps
• Potential publication and citation bias: positive concordance and canonical markers are overrepresented in literature; negative or discordant datasets may be under‑reported (authors note publication bias risk) Publication bias acknowledgement

Actionable takeaways for researchers

1. Prioritize models that phylogenetically and transcriptionally match the human process under study (e.g., macaque or humanized xenografts for AD antigen‑presentation studies) Model selection recommendation
2. Harmonize experimental design across species (same scRNA‑seq protocols, matched injury triggers, controlled housing) to reduce technical confounds — as recommended by the authors Harmonization suggestion
3. Focus on conserved regulatory axes (PU.1/IRF8 and CSF1R/IL‑34/TGF‑β) for interventions aimed at core microglial features; treat species‑specific gene expression differences (e.g., APOE, HLA) as potential modifiers rather than universal targets Conserved axes for intervention

What findings would overturn the review's main synthesis?

• Demonstration across multiple vertebrate lineages that microglia do not derive from yolk‑sac or homologous primitive progenitors (would falsify the conserved ontogeny claim) Falsifiability criteria
• Large-scale, harmonized negative datasets showing identical DAM activation trajectories and transcriptional responses across rodents and humans (would weaken claims of species‑specific disease responses)

Primary citation (the reviewed paper)

Full review: Microglia across evolution (full review)