Depending on the title, there may be more or fewer duties required for the position. While smaller offices may have office assistants perform the duties of secretaries or file clerks, larger offices might have their assistants stick to one duty, such as filing.
Updated August 03, 2017. DNA mutations happen when there are changes in the nucleotide sequence that makes up the strand of DNA. This can be caused by random mistakes in DNA replication or even an environmental influence like UV rays or chemicals.
Genetic mutations. Genetic mutations occur when DNA changes, altering the genetic instructions. This may result in a genetic disorder or a change in characteristics. Mutations can be caused by exposure to specific chemicals or radiation. For example, cigarette smoke is full of chemicals that attack and damage DNA.This causes mutations in lung cell genes, including the ones that control growth.enetic mutations. Genetic mutations occur when DNA changes, altering the genetic instructions. This may result in a genetic disorder or a change in characteristics. Mutations can be caused by exposure to specific chemicals or radiation. For example, cigarette smoke is full of chemicals that attack and damage DNA.