A method of hybridizing an oligodeoxyribonucleotide to a polynucleotide target sequence, the method comprising:forming an oligodeoxyribonucleotide comprising a defined sequence of nucleoside subunits joined by inter-subunit linkages defined by the formula: ##STR1## wherein B is a purine or pyrimidine or an analog thereof and n is between 2 and 48; and (b) contacting the oligodeoxyribonucleotide wi