Office Assistant Tasks. 1  Answer phones, direct calls and take messages. 2  Operate office machines; photocopiers and scanners, facsimile machines, voice mail systems and personal computers. 3  Maintain and update filing, inventory, mailing and database systems. 4  Open, sort and route incoming mail, answer correspondence and prepare outgoing mail.
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.
The smallest single base deletion mutations are believed occur by a single base flipping in the template DNA, followed by template DNA strand slippage, within the DNA polymerase active site. Deletions can be caused by errors in chromosomal crossover during meiosis, which causes several serious genetic diseases. Deletions that do not occur in multiples of three bases can cause a frameshift by changing the 3-nucleotide protein reading frame of the genetic sequence.