Phylogenetic relationships among Triticum L. and Aegilops L. species based on the internal transcribed spacer sequences of nrDNA (ITS)

The research Studies genetic relationships among Triticum L. and Aegilops L. species by direct sequencing of PCR-amplified internal transcribed spacer (ITS) of nuclear ribosomal DNA to investigate the polymorphism in nucleotide sequences among 8 Aegilops L. and 7 Triticum L. species. ITS sequences were aligned with CLUSTAL W 2.1 multiple sequence aligment program. The phylogenetic relationships among species were reconstructed using Unweighted Pair Group Mean Arithmetic Average (UPGMA) and neighbor-joining (NJ) methods. ITS region ranged from 600 to 602 bp. The length of ITS1 was 221-222 bp, and ITS2 was 215-217 bp. The 5.8S subunit was 163 bp long. The G + C content of the ITS1 region ranged from (61.2 to 63.9)% in all Triticum and Aegilops species. The G + C content of the 5.8S subunit was entirely identical in all species, 59.5%. The G + C content of the ITS2 region ranged from (59.9 to 63.5)%. There were 54 variable sites (8.97%) in the entire ITS region. T. dicoccon, T. durum were more variable than other species. The phylogenetic relationships among species were reconstructed using (UPGMA) and discussed. There were mainly three clades in this tree. T. urartu, was separate from T. monococcum. The similarity between T. dicoccoides and T. monococcum could be the result of a recent introgression event.