{TAIL ~ Homology} or identity can be determined by comparing a position in {HEAD ~ each sequence} which may be aligned for purposes of comparison 
{ TAIL ~ Homology } or identity can be determined by comparing a position in { HEAD ~ each sequence } which may be aligned for purposes of comparison
TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH