Alpha-morpholino subunits and polymer compositions composed of alpha-morpholino subunits are disclosed. These subunits can be linked together by uncharged linkages, one to three atoms in length, joining the morpholino nitrogen of one subunit to the 5' exocyclic carbon of an adjacent subunit. Each subunit contains a purine or pyrimidine base-pairing moiety effective to bind by hydrogen bonding to a specific base or base-pair in a target polynucleotide. The polymers of the present invention can be used in place of standard RNA or DNA oligomers for a number of standard laboratory procedures, for example, as probes in solid-phase systems and nucleic acid hybridization analyses. Further, the polymers of the present invention have potential use as therapeutic agents in anti-sense-type technologies.