Oligonucleotides (oligos) are frequently modified with various fluorescent groups to enable detection, imaging, and analysis of nucleic acids. Some common fluorescent modifications used in oligos include:

1. Fluorescein (FAM): FAM is a widely used fluorescent dye that emits green fluorescence when excited by light of appropriate wavelength. It is commonly employed in applications such as real-time PCR, DNA sequencing, and fluorescence in situ hybridization (FISH).
2. Tetramethylrhodamine (TAMRA): TAMRA is a red fluorescent dye often used as a quencher in oligonucleotide probes. It can quench the fluorescence of nearby fluorophores via fluorescence resonance energy transfer (FRET), making it useful for probe-based assays such as qPCR and molecular beacon assays.
3. Cyanine Dyes (Cy3, Cy5, Cy5.5, Cy7): Cyanine dyes are a family of fluorescent dyes with varying emission wavelengths. Cy3 emits green fluorescence, Cy5 emits red fluorescence, and Cy5.5 and Cy7 emit near-infrared fluorescence. They are commonly used in multiplexed assays, microarray experiments, and fluorescence imaging techniques.
4. Alexa Fluor Dyes: Alexa Fluor dyes are a series of highly fluorescent dyes with a wide range of emission wavelengths. They are characterized by their photostability and brightness, making them suitable for various fluorescence-based applications such as immunofluorescence staining, flow cytometry, and microscopy.
5. Rhodamine Dyes (ROX, ROX): Rhodamine dyes emit red-orange fluorescence and are often used as reference dyes in real-time PCR and DNA sequencing reactions. They serve as internal standards for normalization of fluorescence signals, aiding in accurate quantification of target nucleic acids.
6. BODIPY Dyes: BODIPY dyes are a family of fluorescent dyes with high quantum yields and excellent photostability. They are used in various applications including fluorescence labeling, imaging, and detection of nucleic acids and proteins.
7. Quasar Dyes: Quasar dyes are a series of proprietary fluorescent dyes developed by Biosearch Technologies. They offer excellent brightness and photostability, making them suitable for applications such as SNP genotyping, FRET assays, and fluorescence in situ hybridization (FISH).

These are just a few examples of the many fluorescent modifications available for oligonucleotides. The choice of fluorescent dye depends on factors such as emission wavelength, compatibility with detection systems, and specific requirements of the experiment or assay.

GenCefe provides customized DNA oligo modification/labeling services, including more than 100 modifications such as biotin, digoxigenin, phosphate, thiol, sulfhydryl, amino, special bases, and a variety of fluorescent groups. 100% of the delivered modified probes/primers have passed mass spectrometry detection to ensure accuracy and purity, meeting the needs of scientific research and industrial-grade modified primers/probes.