Restriction landmark genomic scanning

Restriction Landmark Genomic Scanning (or RLGS) is a genome analysis method that allows for rapid simultaneous scanning of thousands of landmarks. RLGS employs direct labeling of DNA, which is first cut by a specific series of restriction enzymes, and then labeled by a radioactive isotope (usually Phosphorus 32). A two-dimensional electrophoresis process is then employed, yielding high-resolution results. The radioactive second-dimension gel is then allowed to expose a large sheet of film, which is then developed, yielding a visual representation of the results in the form of an autoradiograph. These auto-rads can be examined against each other, revealing any changes in gene expression that lead to visual differences in the film. Each autoradiograph contains thousands of spots, each corresponding to a labeled DNA restriction landmark.

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RLGS becomes very useful when doing full genome scans, and can effectively do the work of thousands of polymerase chain reactions at once. It readily detects alterations deviating from normal, and thus is exceptionally effective in identifying hyper/hypomethylation in tumors, deletions or amplifications of genes, or simply changes in gene expression throughout the development of an organism.

Sources

• http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=8388788
• http://www.informatics.jax.org/searches/accession_report.cgi?id=MGI:71287
• a picture of an auto-rad from Roswell Park Cancer Institute