In 1993, two research groups led by Ambros [1] and Ruvkun [2] independently discovered in Caenorhabditis elegans (C. elegans) that the lin-4 gene, which controls larval development, does not encode a protein but instead produces a small RNA of 22 nucleotides (nt) in length, named lin-4. In 2000, Ruvkun’s group [3] further identified another small RNA molecule, let-7, which is 21 nt in length and regulates developmental timing in C. elegans. Due to their similar functions in controlling development, lin-4 and let-7 were initially referred to as small temporal RNAs (stRNAs). Subsequently, researchers discovered many other small RNA molecules of similar lengths in various organisms, deepening the understanding of lin-4 and let-7 functions and revealing that these stRNAs are actually part of a specific class of small RNAs. In October 2001, three research teams led by Tuschl [4], Bartel [5], and Ambros [6] simultaneously published papers in Science, formally naming these small RNAs as microRNAs (miRNAs). Since then, with the continuous advancement of molecular biology techniques, thousands of miRNAs have been identified in various species, including humans, mice, rats, zebrafish, Drosophila, rice, Arabidopsis, and many other plant and animal taxa, opening up a completely new and expansive research field.