chromosome walking
Post on 24-Jan-2017
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Chromosome walking
Saakre ManjeshCPBMBKAU
Introduction
• Chromosome walking is a method of positional cloning used to find, isolate, and clone a particular allele in a gene library.
• Developed by Welcome Bender, Pierre Spierer, and David S. Hogness in the Early 1980's.
KNOWN
Construction of library
1A DNA fragment from a chromosome contains and identify sequence (usually
a gene)
Fragment 2
2
Fragment 1
Fragment 3
Prepare restriction map
Use this sequence as probe
Probe produced by subcloning ; subclone -1
Hybridize with clones from genomic library
Isolate fragment-2 prepare restriction map of fragment-2
Successive fragments
12
3
1 2 3
Overlapping sequences
Use this sequence as probe
Probe produced by subcloning ; subclone -2
Hybridize with clones from genomic library
3
continue
Application
• The analysis of genetically transmitted diseases, to look for mutation
• Discovery of single-nucleotide polymorphism of different organisms.
• To know the unknown flanking region of the chromosome• Now a days it can be use for the metagenomics process to
know the genome sequence of the unknown organism
Disadvantages
• Speed of chromosome walking • Difficulty of walking through the repeated sequence that are
scattered through the gene.
• Chromosome walking could easily be stopped by un clonable sections of DNA.
• A solution to this problem was achieved with the advent of chromosome jumping (Marx, 1989), which allows the skipping of unclonable sections of DNA
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