Poly(A) is widely used in molecular biology and genetic research as a tool for studying mRNA and gene expression. It is commonly employed in techniques such as poly(A) tailing to stabilize mRNA and enhance its translation efficiency. In RNA sequencing, poly(A) selection is a critical step to isolate mRNA from total RNA, enabling the study of transcriptomes. Additionally, poly(A) sequences are utilized in the synthesis of cDNA and in the development of probes for detecting specific RNA molecules. Its applications also extend to the creation of poly(A) tails in synthetic RNA for therapeutic purposes, such as mRNA vaccines, to improve stability and efficacy in vivo.