关键词: 植物远缘杂交 杂种 多倍体 表观遗传变异

Abstract:

Sexual hybridization between different species or genera in plants is a common phenomenon in nature, which represents a predominant model of speciation, whereby rapid hybridization barrier may form and new species can emerge sympatrically with its parental ones. These wide hybridizations are also an effective means for crop improvement. But the mechanistic basis by which new species forms via this means remains largely elusive. Recent studies over the last several years have demonstrated that wide hybridization and subsequent genome doubling （pelyploidy） often induce an array of variations that could not be explained by the conventional genetic paradigms. A large proportion of these variations are epigenetic in nature. All hybridization and/or pelyploidy-associated epigenetic variations so far uncovered are alterations in cytosine DNA methylation. Nonetheless, it is conceivable that other epigenetic modifications like histone covalent modification and chromatin remodeling, which were known as interlaced with DNA methylation, may also subjective to modifications upon hybridization and/or pelyploidy. Further basic studies on epigenetic variations generated by wide hybridization and polyploidy may shed light on the mechanisms generating these variations, and will enhance our understanding on their evolutionary significance, as well as enable us to more effectively utilize these variations in crop breeding.

Key words: plant widehybridization, hybrid , polyploid , epigenetic variation