Chromosome Walking

As a result of genetic investigation, we may know the approximate chromosomal location of a particular gene. Using this information to clone the gene is referred to as positional cloning. One of the simplest versions of this is chromosome walking, a method based on hybridization. This approach is used when one segment of DNA has already been cloned and the neighboring genes are of interest.

The chromosome that has the target gene can be identified and isolated by fluorescence in situ hybridization (FISH) followed by fluorescence activated sorting as described in Ch. 21.The chromosome of interest is then cut into manageable fragments with a suitable restriction enzyme. The original cloned fragment of DNA is used as the cDNA library Collection of genes in their cDNA form, lacking introns chromosome walking Method for cloning neighboring regions of a chromosome by successive cycles of hybridization using overlapping probes

Lyse cells

EXTRACT & PURIFY mRNA

Eukaryotic cells

Lyse cells

EXTRACT & PURIFY mRNA

mRNA mixture mRNA mixture

Reverse transcriptase

USING OLIGO (dT) PRIMER

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