Once SNPs of interest are identified, annotation tools interpret their biological significance. Major software include ANNOVAR, SnpEff, and VEP (Variant Effect Predictor), which attach information such as what gene a SNP lies in, whether it changes protein-coding sequence, or if it has known disease associations. These tools integrate multiple databases like dbSNP, ClinVar, OMIM, and gnomAD to provide population frequency data, evolutionary conservation scores, and clinical significance of variants. Functional annotation also includes predicting the impact of non-coding variants using resources like ENCODE, Roadmap Epigenomics, and tools such as CADD, FATHMM, and SIFT that use machine learning to estimate deleteriousness scores for variants.