cel-mir-54: Cel-mir-54 is a specific miRNA target that was addressed in a study that aimed to overcome the problem of non-specific hybridizations associated with isomiRs. The study incorporated PG tracts with G4-forming ability into the design of molecular probes for miRNA targets. This approach allowed for more stringent discrimination of cel-mir-54 from mismatched isomiRs [PMC5690596]. To enable relative comparison across the analyzed samples, spike-in normalization was performed using a synthetic C. elegans derived cel-mir-54 sequence [PMC6197019]. The use of spike-in normalization with synthetic cel-mir-54 allowed for accurate comparison and quantification of cel-mir-54 expression levels across different samples. This normalization method helps to account for any variations in sample preparation and sequencing efficiency, ensuring reliable and accurate results [PMC6197019]. By incorporating PG tracts with G4-forming ability into molecular probes and using spike-in normalization, the study successfully addressed the challenges associated with non-specific hybridizations and achieved more stringent discrimination of cel-mir-54 from mismatched isomiRs, providing a valuable approach for studying miRNA targets [PMC5690596][PMC6197019].