Epigenetic effects,which were defined clearly in recent years,are most often used to denote all those somatically heritable changes in gene expression that do not involve changes in DNA sequence.

• 后生效应是近几年才定义清楚的一类现象，指所有那些DNA序列没有改变的基因表达后体细胞的遗传表型发生改变的现象。