Nucleic acid stains are chemical compounds used to detect and visualize nucleic acids, such as DNA and RNA, in biological samples. These stains bind specifically to nucleic acids, allowing researchers to observe their presence and quantity under a microscope or through other imaging techniques. Common examples include ethidium bromide and SYBR Green. These stains are essential tools in molecular biology and genetics, aiding in various applications like gel electrophoresis, where they help identify the size and concentration of nucleic acid fragments. By providing a clear visual representation, nucleic acid stains facilitate the study of genetic material and its functions.