To study possible epigenetic changes accompanying polyploid speciation, genomic DNA from natural polyploid wheats and their putative diploid progenitors were digested with a pair of isoschizomers Hpa Ⅱ/ Msp Ⅰ and hybridized to 21 different types of low-copy DNA sequences. It was found that cytosine methylation changes were abundant in natural polyploid wheats after their speciation. The hybridization of the same set of sequences to a synthetic hexaploid wheat along with its parental lines indicated that the extensive DNA methylation changes already existed in the early generations (85,86 and 87) of this plant. Moreover, the high similarity of the changed restriction fragment length polymorphism (RFLP) patterns among three randomly chosen individual plants suggested that the methylation changes occurred even earlier, and/or were of a nonrandom nature. The changed patterns were stably inherited in the three successive selfed generations. Though methylation changes are probably a genome-wide occurrence, To study possible epigenetic changes accompanying polyploid speciation, genomic DNA from natural polyploid wheats and their putative diploid progenitors were digested with a pair of isoschizomers Hpa II / Msp I and hybridized to 21 different types of low-copy DNA sequences. It was found that cytosine methylation changes were the same in natural polyploid wheats after their speciation. The hybridization of the same set of sequences to a synthetic hexaploid wheat along with its parental lines indicates that the extensive DNA methylation changes already existed in the early generations (85, 86 and 87) of this plant. Moreover, the high similarity of the changed restriction fragment length polymorphism (RFLP) patterns among three randomly chosen individual plants suggested that the methylation changes occurred earlier, and / or were of a nonrandom nature. The changed patterns were stably inherited in the three even selfed generations. Though methylation changes are probably a geno me-wide occurrence,