GISH ( Genomic In Situ Hybridization)

What is GISH? 

-It is a cytogenetic technique that allow the detection and localization of specific nucleic acid sequence on morphologically preserved chromosome using genomic DNA of donar spacies as prob. 

 • It is quick , accurate, sensitive, informative and comparative approach. 

• This technique is an advancement in the fluorescence in Situ hybridization (FISH) technique. 

 Background-

- GISH for plants was developed in 1987 by 

  M. D. Bennett. 

- GISH was mainly developed for the animal hybrid cell in 1986 . 

- In 1987 the plant breeding Institute Cambridge was used this technique in plants. 

Principles -

- This technique involves the extraction of labelling DNA of one organisms and to use probe to target the genome of another organisms. 

- The part of genome that are similar to the probe hybridize to from a probe target complex

Steps (Procedure) 

• Take probe DNA. 

• Blocking DNA fragmentation. 

• preparation of side. 

• Denaturation of probe and blocking DNA in the hybridization mixture. 

• Addition of probe and blocking DNA with hybridization mixture. 

• Chromosome DNA denaturation

• Hybridization of blocking DNA and probe in the target sequence of the chromosome. 

• Detection of probe in the chromosome of one parents. 

• Chromosome DNA molecule of second parent related to unlabeled blocking DNA. 

• visualization of hybridization signals associated to a probe in Fluorescence microscope. 

• Unmarked chromosome are visualize with blue color. 

Application - 

•  It is used to identify Chromosomal rearrangement in cancer patients. 

• Chomosomal identification in cell. 

• Detect the specific nucleotide sequence within cell and tissue. 

• Unique point among the studies of cell biology, cytogenetic and molecular technique. 

• It is possible to detect single copy sequence of chromosome with probe. 

• Genomic in Situ hybridization is a potentially powerful tool for studying genome evolution and biosystematics. 

• It will useful for investigating the origins of wild and cultivated polyploid plant species.