Single nucleotide polymorphisms (SNPs) present at the high-molecular-weight glutenin Dy locus provide new insights into the origins and evolution of Triticum aestivum L

摘要

The occurrence of single nucleotide polymorphisms (SNPs) in part of the promoter region of the high-molecular-weight glutenin Dy locus was investigated in a large collection of T.aestivum and its progenitor Ae.tauschii. PGR amplification of the regionwas followed by phylogenetic analysis of the DNA sequence data. The analysis shows that although this locus is polymorphic T.aestivum and Ae.tauschii share only two alleles. The existence of two ancestral type alleles supports the theory that hexaploidwheat had at least two origins. One of the ancestral alleles corresponds to subunit 12 of the Glu-Dla haplotype. The second ancestral allele very likely gave rise to subunit 10 of the Glu-Dld haplotype. This process probably occurred in T.aestivum, as the allele corresponding to this haplotype was not found in the Ae.tauschii populations studied. T.aestivum is approximately 10,000 years old yet the number of unique alleles present at the Glu Dy locus is much greater than expected when comparisons are made with the 2.5 - 4.5 million years old Ae.tauschii genepool. The D genome of wheat is thought to be a composite of several sources however this study suggests that at least some of this variability evolved after the species originated.