In bacteria, the methionine that initiates the formation of a polypeptide chain differs from subsequently added methionines in that

In bacteria, the methionine that pledges the formation of a polypeptide chain be at variance from subsequently added methionine in that a formyl group is committed to the initiating methionine. In addition, in the topic of genetics, the small ribosomal sub units bind to an mRNA sequence near the 5’ end of the transcript best describes the first step in the formation of the translation initial complex. 

They create genetic variations