Conservation and variability of sequence-tagged microsatellite sites (STMSs) from chickpea (Cicer aerietinum L.) within the genus Cicer

The conservation of 90 microsatellite-flanking sequences from chickpea in 3 9 accessions of eight annual and 1 accession of a perennial species of the genus Cicer was investigated. All of the primer sequences successfully ampl ified microsatellites in related species, indicating the conservation of mi crosatellite-flanking sequences in chickpea's relatives. However, the degre e of conservation of the primer sites varied between species depending on t heir known phylogenetic relationship to chickpea, ranging from 92.2% in C. reticulatum, chickpea's closest relative and potential ancestor, down to 50 % for C. cuneatum. A phylogenetic tree revealed that chickpea and the other members of its crossability group were more closely related to the perenni al C. anatolicum than to other annual species of the genus. Considerable va riation in size and number of amplification products between and within spe cies was observed. Sequence analysis of highly divergent amplification prod ucts proved that variation is either due to large differences in the number of microsatellite repeats or to the amplification of a locus unrelated to the one amplified from chickpea. Sequence information and bootstrapping usi ng PAUP suggested that STMSs derived from chickpea may be efficiently and r eliably used for synteny studies in chickpea's crossability group, includin g C. anatolicum. However, care should be taken when applying these markers to other species of the genus. Considering the data presented here and the known historical record, the age of section Monocicer including chickpea, i s estimated to be about 100,000 years.