Abundance and polymorphism of di-, tri-and tetra-nucleotide tandem repeats in chickpea (Cicer arietinum L.).

The abundance and polymorphism of 38 different simple-sequence repeat motifs was studied in four accessions of cultivated chickpea (Cicer arietinum L.) by in-gel hybridization of synthetic oligonucleotides to genomic DNA digested with 14 different restriction enzymes. Among 38 probes tested, 35 yielded detectable hybridization signals. The abundance and level of polymorphism of the target sequences varied considerably. The probes fell into three broad categories: (1) probes yielding distinct, polymorphic banding patterns; (2) probes yielding distinct, monomorphic banding patterns, and (3) probes yielding blurred patterns, or diffused bands superimposed on a high in lane background. No obvious correlation existed between abundance, fingerprint quality, and the sequence characteristics of a particular motif. Digestion with methyl-sensitive enzymes revealed that simple-sequence motifs are enriched in highly methylated genomic regions. The high level of intraspecific polymorphism detected by oligonucleotide fingerprinting suggests the suitability of simple-sequence repeat probes as molecular markers for genome mapping.