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