DNA probe. Definition

Medical Definition: DNA probe

DNA fragment of synthetic or natural origin, used in experiments of DNA-DNA hybridization (eg., A Southern blot) or DNA-RNA (eg., A Northern Blot) to detect the presence of molecules DNA or RNA, respectively, that have similar nucleotide sequence. To this end, DNA probes are labeled with radioactive isotopes (typically with 32P) or non-radioactive molecules (eg., Biotin, digoxigenin). The development of hybridization assays with DNA probes has been a revolution in disciplines as diverse as the phylogeny (allowing, for example, to clarify the relationships among living things) or the clinical microbiology (helping the diagnosis of certain infectious diseases) .

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