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