基因表达模式(patterns of gene expression)受细胞物质外基因所控。外基因，高于基因，通俗点说，基因之外(前缀epi-，意即上面)。
These patternsofgeneexpression are governed by the cellularmaterial- the epigenome - that sits on top of the genome, just outside it (hence the prefixepi -, which means above).