植物表观遗传学Epigenetics（表观遗传学）:是指以不涉及到DNA序列的改变、但可以通过有丝分裂和减数分裂进行遗传的生物现象。自然界中的表观遗传学现象：Paramutation最早的例子来自果蝇的变化。Muller, H.J. (1930). Types of visible variations induced by x-rays in Drosophila.J Genet. 22, 299334.Hinton, T., and Goodsmith, W. (1950). An analysis of phenotypic reversions at the brown locus in Drosophila. J. Exp. Zool. 114, 103114.Paramutation has been extensively characterized at three maize loci: r1,b1 （helixloop-helix (bHLH) factors）, and pl1(myb)Brink (1956, 1958) 首先描述了r1基因的 Paramutat
