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Digoxigenin is widely used as a nonradioactive label for in situ hybridization to locate DNA sequences along chromosomes in plants (e.g., 1-3) and animals. In many cases, its use is similar to biotin (chapter 25, or e.g., 4), but digoxigenin labels may give lower unspecific background signal and therefore enable more efficient detection of short or low copy sequences. Digoxigenin is usually incorporated into the DNA enzymatically by nick translation, random priming, polymerase chain reaction (PCR), or end labeling using the modified nucleotide digoxigenin-11-dUTP (seechapter 10 and chapter 11). [ABSTRACT FROM AUTHOR]

Chromosomal in situ hybridization enables determination of the presence and location of DNA sequences complementary to a labeled probe along chromosomes and within interphase nuclei. The use of directly fluorochrome-labeled probes means that sites of probe hybridization can be directly visualized. Lengthy detection procedures, as in the indirect immunochemistry methods to detect biotin or digoxigenin, are not needed. However, because there is no signal amplification, sensitivity is limited and the system is used mostly to detect middle- to high-copy number (Fig. 1) or pooled probes, although antibody amplification of some fluorochrome labels is possible (1), and then the method must be evaluated in comparison with digoxigenin (chapter 27) or biotin (chapter 25). [ABSTRACT FROM AUTHOR]