siRNAs are main involved in gene silencing via RISC (RNA induced silencing complex )formation while miRNAs have multiple functions out of which most important one is gene regulation. While Piwi interacting RNAs (piRNAs) are specific to animal system. They form RNA-protein complexes with Piwi protein and these are mainly involved in retrotransposon silencing mainly during spermatogenesis. They are primarily functional during developmental stages. lncRNAs are different in length they generally >200nt in length and have multiple function. They can act as miRNA target mimics, help in epigentic regulation, chromatin remodelling and many such events.