Variation in CoxII Intron in the Wild Ancestral Species of Wheat

To study the maternal lineage and evolution of polyploid species of wheat, variation in mitochondrial DNA was investigated in Triticum and Aegilops by PCR-aided RFLP analysis. A 1.3 kb region containing the intron of coxII was studied using 20 accessions from five species of Sitopsis section of Aegilops, one species of Einkorn wheat, four species of tetraploid wheat, and one species of common wheat. Only three restriction site changes and a single deletion/insertion were found among 884 restriction fragments surveyed. This fact suggests the highly conserved nature of this region within Triticum and Aegilops. Four haplo-types were recognized in coxII intron. A parsimonious relationship indicated that three haplo-types were independently derived from one prototype which was found in wild Einkorn and Aegilops species except for Ae. speltoides. All but one accession of Ae. speltoides possessed a derivative haplo-type, common in Timopheevi wheat. The result supported the hypothesis that Ae. speltoides donated the G genome to Timopheevi wheat; however did not agree with that Ae. speltoides was the B genome donor to the Emmer and common wheat.