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