{TAIL ~ The SIR2 gene family} of {HEAD ~ proteins} is conserved from bacteria to man  
{ TAIL ~ The SIR2 gene family } of { HEAD ~ proteins } is conserved from bacteria to man
TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH