[donna14]

In replica plating method to screen mutants, the organism is subjected to radiation or exposed to chemical to induce the mutation. The mutants can be identified by a reduction in the colony size or change in pigmentation etc. Sub culture is made by replica plating the master culture. The sub cultured plate is subjected to mutation and incubated for growth. Then the plate subjected to mutation is replica plated onto a fresh medium and incubated to observe phenotypic variations. This method can be used to identify the dosage of radiation or chemicals required to cause mutations. If this is repeated with different dosage levels, the finally left colony will be having most resistant cells for the particular mutagen.

Prevention is better than cure. But there is no effective prevention of cancer. Surgery, radiotherapy and chemotherapy are some procedure to cure cancer. But they are not harmless and secured. Genetic engineering may be the latest solution of cancer prevention. Some research has been done to discover new path of cancer prevention through genetic engineering. Genetic changes caused by events such as mutation and agents such as viruses are recognized for research. Damaged genes are trying to recover in the prevention of cancer. If the genetic factors and processes which are responsible for cancer can be controlled in the primary stage, the further progression of cancer will be controlled. Those works must be done by genetic engineering. This genetic engineering ensures the protection of cancer cells from further mutation. Genetic engineering is done if cancer is affected by genetic problems. If carcinogens create cancer then preventive steps should be taken against carcinogens. Genetic engineering may be the best solution for cancer. But this matter is still under research. Our expectation may be fulfilled in the future.