Chromosome walking

I include what are the steps are involved in the chromosome walking technique.

1. CHROMOSOME WALKING SIVASANGARI SHANMUGAM

2. CHROMOSOME WALKING INTRODUCTION : A technique which produces set of overlapping DNA clones for studying segments of DNA larger than can be cloned individually. A method for the analysis of larger region of DNA, in which a each end of a large single cloned DNA fragment is separately to screen recombinant DNA genome library for other clones containing neighbouring sequences. Chromosome walking was developed by Welcome Bender , Pierre spierer & David S.Hogness in the early 1980 s.

3. CHROMOSOME WALKING The technique of chromosome walking involves the following steps ; 1. From genomic library select a clone of interest (identified by probe) & sub clone a small fragment from one end of the clone. 2. The sub cloned fragment of the selected clone may be hybridized with other clones in the library & a second clone hybridizing with the sub clone of the first clone is identified due to presence of overlapping sequence.

4. 3. The end of the second clone is then sub cloned & used for hybridization with other clone to identify a third clone having overlapping region with the sub cloned end of the second clone 4. Third clone identified as above is also sub cloned & hybridized with clones in the same manner & the procedure may be continued. 5. Restriction map of each selected clone may be prepared & compared to know the regions of overlapping so that identification of new overlapping restriction sites will amount to walking along the chromosome or along a long chromosome segments .

5. DISADVANTAGES Limitation in the speed of chromosome walking due to small size of the fragments. If the markers were too far away, it simply was not a viable option. The difficulty of walking through the repeated sequence that are scattered through the genes.

6. APPLICATION Used to find mutation and analysis of genetically transmitted disease Used to detect the single nucleotide polymorphism in different organisms .

7. REFERENCE http://feedforbiotech.blogspot.com/2011/03/chromosome-walking.html http://www.genevoguebiotech.com/2012/09/chromosome-walking.html http://www.wisegeek.com/what-is-chromosome-walking.html http://wiki.answers.com/Q/Applications_of_chromosome_walking_and_jumping#ref1

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