We do peripheral blood chromosome analysis, in the last month we could not get G band, at the same time we got bands on chromosomes that stained for C band. I do not know if the increase of humidity was the main reason. But I will write the protocol to recommend me change some details that may help to get the G-bands again.

Preparation

- 0.075 g of trypsin powder dissolved in 100 ml of PBS, then heated in a water bath 56-58C.

- 85ml of D.water + 5 ml KH2PO4 + 5ml Na2HPO4 + 5ml Geimsa stain. pH =6.9

Start Staining

- Slides inseted in trypsin Jar at 56-58 C. for 40 seconds.

- Washing slides quickly in cold PBS for less than 1 second.

- Slides inserted in Giemsa jar for 3 min and 30 Sec.

- Twice wash quickly in D.water.