Two important sources for mutation(unavoidable) a Inaccuracy in DNA replication (10-7 is not accurate enough) Errors(错误) a Chemical damage to the genetic material (environment) Lesions(损害伤害 arose from spontaneous damage) Damage(损害伤害 caused by chemical agents and radiationTwo important sources for mutation (unavoidable) ◼ Inaccuracy in DNA replication (10-7 is not accurate enough) Errors (错误) ◼ Chemical damage to the genetic material (environment) Lesions (损害,伤害arose from spontaneous damage) Damage (损害,伤害 caused by chemical agents and radiation