Hello everone,
I need different protocols for chromosomes bandings including the G-banding protocols. Is there anyone who is using these protocols and can provide it for me?
Thank you for your help
G-banding: karyogram of human male using Giemsa staining.
G-banding, G banding, or Giemsa banding is a technique used in cytogenetics to produce a visible karyotype by staining condensed chromosomes. It is useful for identifying genetic diseases through the photographic representation of the entire chromosome complement.[1] The metaphase chromosomes are treated with trypsin (to partially digest the chromosome) and stained with Giemsa stain. Heterochromatic regions, which tend to be rich with adenine and thymine (AT-rich) DNA and relatively gene-poor, stain more darkly in G-banding. In contrast, less condensed chromatin—which tends to be rich with guanine and cytosine (GC-rich) and more transcriptionally active—incorporates less Giemsa stain, and these regions appear as light bands in G-banding. The pattern of bands are numbered on each arm of the chromosome from the centromere to the telomere.This numbering system allows any band on the chromosome to be identified and described precisely.The reverse of G‑bands is obtained in R‑banding. Banding can be used to identify chromosomal abnormalities, such as translocations, because there is a unique pattern of light and dark bands for each chromosome.
It is difficult to identify and group chromosomes based on simple staining because the uniform colour of the structures makes it difficult to differentiate between the different chromosomes. Therefore, techniques like G‑banding were developed that made "bands" appear on the chromosomes. These bands were the same in appearance on the homologous chromosomes, thus, identification became easier and more accurate. The less condensed the chromosomes are, the more bands appear when G-banding. This means that the different chromosomes are more distinct in prophase than they are in metaphase.
Thank you Nirmala,
In fact I know about G-banding, but I need different protocols (procedure of staining) to try in my lab. There is a procedure with Trypsin and another one without trypsin but using other banding method. I just need to have them or get a link to.
you can try the R- banding (reverse banding) check the protocol on line, but G- banding is more useful and satisfying
"https://onlinelibrary.wiley.com/doi/book/10.1002/9781119061199"
Hi Mona,
see the above link for ultimate resource of any question on cytogenetics. This is new edition with many tried and tested variations of banding with art and science behind it. This book is a must, as there are not many text books that can serve as a protocol book in the field of chromosomes. It is from the cytogenetics community, one can become a member, sharing the website, [https://agt-info.org/], see their Newsletter, and publish etc. in addition to getting this book, a video explaining chromosome spread etc.
Dear Diana Shahin
Would like to add that R-banding and G-banding are complimentary, one can not replace the other, they serve different purposes, and hence none is better than the other.
Dear Nirmala
Would like to know your experience with the chromosome studies, interesting to see your reply, as it is rare and pleasant surprise to see people from dentistry so well versed with this topic.
Hope this helps.
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