within the 5' CpG dinucleotide of the NGFIA consensus sequence within the exon 17 GR promoter of the biological offspring of low-LG mothers cross-fostered to high-LG dams is indistinguishable from that of the biological offspring of high-LG mothers. The reverse is true for the offspring of high-LG mothers fostered to low-LG dams. These findings suggest that variations in maternal care alter the methylation status within specific sites of the exon 17 promoter of the GR gene and represent the first demonstration of a DNA methylation pattern established through a behavioral mode of programming. Essentially, these findings provide a direct example of epigenetics: a modification of the genome that does not involve an alteration in sequence, and is thus distinctive from what is thought to be Lamarckian transmission (which would involve a change in sequence transmitted through genetic inheritance). This example is also distinct from parental imprinting, a well-established paradigm of inheritance of an epigenetic marker, that requires germ-line transmission.116,117
