Tracking Evolution of SARS-CoV-2 NSP7: Mutation Insights from 2,731 Genomes

This work builds upon my recent study titled "Mutation Profile Analysis of 3,252 SARS-CoV-2 Genomes from January to Early May 2025: Evidence of High Diversity and Limited Convergent Evolution in NSP7, NSP8, NSP12, and NSP14" published on Figshare (DOI: 10.6084/m9.figshare.29137385.v1 ). In that global-scale analysis of 3,252 genomes , I reported no recurrent mutations in key replicase genes including NSP7 , indicating high genomic diversity and limited convergent evolution across the early pandemic period. In this focused follow-up investigation, I re-analyzed the same curated dataset of 2,731 high-quality sequences using refined methods and deeper inspection of individual gene regions. The updated analysis revealed four recurring amino acid substitutions in NSP7, N79K, T85I, R115G, and E133D which cluster within functionally important domains such as the RNA-binding interface and the NSP8 interaction region. This suggests that while overall convergence remains low, certain positions in NSP7 may be under subtle selective pressure, warranting further structural and functional investigation. I encourage researchers to have critical evaluation of these findings in light of ongoing surveillance data and emphasize the importance of open science and reproducibility through shared, visualizations, and mutation matrices. This work is intended to support open research into SARS-CoV-2 evolution, particularly in understudied non-structural proteins.