A technique permitting identification of particular deoxyribonucleic acid or ribonucleic acid sequences while these sequences remain in their original location in the cell. A cell or tissue is treated with a fixative and then exposed to a labeled (by radioactivity or fluorescence) single-stranded nucleic acid probe that hybridizes with the targeted nucleic acid sequence, revealing its location on a chromosome band when the hybridized sequence is analyzed microscopically.

Read more: http://www.answers.com/topic/in-situ-hybridization#ixzz3T76ALRKI