A simple technique for demonstrating heterochromatin inNigella

citation_journal_title=Chromosoma; citation_author=A. T. Natarajan, G. Ahnstrom; citation_volume=28; citation_publication_date=1969; citation_pages=48; citation_doi=10.1007/BF00325989; citation_id=CR1 B. S. Gill, G. Kimber, Proc. natn. Acad. Sci., USA, in press. The enzyme mixture is prepared by mixing equal parts of 5% pectinase and cellulase solutions to which 2–3 drops of 1N HCl were added for each 5 ml of the mixture. The 2X-SSC solution is made with 0.887 g of NACl and 0.411 g of trisodium citrate in 100 ml of distilled water. The stock Giemsa solution is made by mixing 1 g Giemsa powder (Fisher) in 66 ml of glycerine and heating it for 2 h in a 60°C oven with frequent agitation. Then 66 ml of absolute methanol is added and this mixture is cooked for 2 days in 60°C oven with frequent agitation. The working staining solution is made by mixing 5 ml of stock Giemsa solution, 1.5 ml Macllvaine buffer (pH 7.0), 1.5 ml absolute methanol and 50 ml of distilled water. This staining mixture is filtered and used.