Contribution of chloroplast DNA in the biodiversity of some Aegilops species
Four Aegilops species (Aegilops longissima, Aegilops speltoides, Aegilops searsii and Aegilops caudata) belonging to the family Poaceae were used in this study. Nucleotides of 1651 bp from 5.8 S rRNA gene and the intergenic spacers trnT-trnL and trnL-trnF from the chloroplast DNA were combined together in order to investigate the genetic diversity among the earlier mentioned species. Maximumparsimony and Neighbor-joining computational methods for tree building were applied to construct the relationship among the Aegilops species. In all trials, one parsimonious tree was obtained, in which, the A. speltoides was the oldest and was out of a cluster containing the other three Aegilops species. A. searsii and A. caudata were sisters to each other, while A. longissima was basal in this cluster. These findings did not agree with previous karyotypic studies in which A. searsii was the oldest, and A. caudata was recently originated, while both A. longissima and A. speltoides were intermediate. The present study therefore revealed the significance of molecular markers in clarifying the genetic diversity on the inter- and intra-specific levels. These markers can also be applied for taxonomic consequences and have an economic importance in the genetic amelioration programs.
Key words: Aegilops, chloroplast DNA, biodiversity, systematic.