by Habib Ma­roon — Retrons are an un­der­stud­ied type of prokary­otic retroele­ment re­spon­si­ble for the syn­the­sis of an enig­matic species of small ex­tra-chro­mo­so­mal satel­lite DNA termed mul­ti­copy sin­gle-stranded DNA (ms­DNA). ms­D­NAs are ac­tu­ally com­posed of both a sin­gle-stranded (ss) DNA and a ss­RNA. The 5' end of the ms­DNA is co­va­lently bonded to an…