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