In the present report the potential of (CAC)5 is demonstrated for DNA fingerprinting in rice. Based on the fingerprint data, (CAC)5 was estimated to differentiate up to 6.3 x 10(8) genotypes of rice. In a search for homologous sequences in rice transcripts, four oligonucleotide probes, namely, (CAC)5, (GATA)4, (GACA)4, and (TG)10, were used. Among these probes, (CAC)5 showed hybridization to total rice RNA in a tissue-specific manner; while a band at 1.2 kb was common in both seed and leaf RNA, there were additional prominent bands at 1.9 and 2.3 kb in seed and leaf RNA, respectively. When (CAC)5 was hybridized to poly(A)+ RNA, in addition to a band at 1.2 kb in seed and leaf, hybridization was observed only in seed to heterogeneously sized RNAs.