A degree of {TAIL ~ homology} between sequences is a function of the number of matching or homologous positions shared by {HEAD ~ the sequences} 
A degree of { TAIL ~ homology } between sequences is a function of the number of matching or homologous positions shared by { HEAD ~ the sequences }
OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD