*3.2. Search Strategy*

Each MGI database-derived entry was curated manually or automatically to identify candidate models that reported PR degeneration as a phenotype, as described above. In the case of PubMed entries, although the automated approaches were useful for quickly identifying genes that satisfied our criteria, neither was comprehensive, and additional candidate models were identified by review of the title and abstract from some of the remaining articles in the full collection of 9535 articles. Subsequently, an independent coauthor identified an original publication for each candidate gene and determined if PR cell loss was reported. If su fficient evidence for PR cell loss was obtained, the gene and mouse model was assigned to one of 11 categories. Genes within each category were curated further by coauthors who identified alternate alleles and extracted information regarding the disease phenotype induced by the disruption of a gene. Each entry in Table S1 is the result of the examination of an original article (indicated by PubMed ID numbers, PMIDs) and data from MGI to capture information such as mutation type, associated human diseases, and disease onset and progression.

### *3.3. Comparative Analysis and Updating the MGI Database*

Once our final list was completed, we used tools in Excel to compare it to a list constructed from online tables downloaded on 8 December 2019, from RetNet, a public compilation of human genes linked to inherited RD. We also provided our data to the MGI team at JAX, who assigned allele nomenclature, added strain information for newly described mutants, and updated phenotype data for alleles that were present in the MGI database but not ye<sup>t</sup> annotated with respect to PR cell loss. This review has been referenced at MGI so that the alleles documented in the article can be examined using MGI tools or downloaded in tabular format for analysis with other software. The collaborative approach between mouse phenotyping experts and the MGI team may be attractive for ensuring that this useful resource remains current in the face of limited funding, personnel, and time.
