The invention provides methods, kits, and compositions for ligation of PNA-DNA chimeric probes and oligonucleotides when they are hybridized adjacently to template nucleic acids using ligases and ligation reagents. Structural requirements of the chimeras for ligation include 5 to 15 contiguous PNA monomer units, 2 or more contiguous nucleotides, and a 3′ hydroxyl or 5′ hydroxyl terminus. The chimera and/or oligonucleotide may be labelled with fluorescent dyes or other labels. The methods include, for example, oligonucleotide-ligation assays (OLA) and single nucleotide polymorphism detection.