Chromosome Resolution Additive (CRA), a newly found commercial formulation promises to consistently prevent chromosome contraction as well as encourage chromosome elongation by loosening the chemical bonding within the supercoiled structure of the chromosome. The result delivers prophase quality chromosomes. Designed especially for tissues resistant to existing prophase techniques; be it the bone marrows or solid tumour samples.
The CRA comprises no ethidium bromide or thymidine. It is a simple-to-use product which is believed to improve chromosome resolution and is safer than ethidium bromide. A working solution of CRA is simply added to the culture approximately 90 minutes prior to metaphase arrest. This product is meant to increase the QA band level on different cytogenetics sample types. A colchicine antagonist, it diminishes the chromosome shortening effect of colchicine. It can also be used alongside ethidium bromide for extra chromosome length.