epigenetic influence

"Whereas the genome was once believed to almost exclusively determine our inheritance, it is now widely accepted that epigenetic influences, especially those occurring in the womb, affect and sometimes even override gene expression at all levels and thereby modify brain development (Gottlied, 1998; Harper, 2005; Keller, 2000; Lickliter and Honeycutt, 2003; Natanielsz, 1999; Petronis, 2001). The maternal environment affects immune function, heart disease, diabetes, and cancer risk (Nathanielsz, 1999; Pteronis, 2001) and even gross physical appearance in some cases (Gottlieb, 1998); it has also been shown to have an especially powerful influence on brain development and behaviour, and may even be considered a source of speciation (Lickliter and Honeycutt, 2003). What is critical from the standpoint of human brain evolution is that maternal effects are trans-generational in that, for example, a mother with high dopamine levels can prenatally pass those levels on to her children and, in turn, they to their children (Harper, 2005; Lickliter and Honeycutt, 2003; Nathanielsz, 1999)."

excerpted from "The Dopamingeric Mind in Human Evolution and History" by Fred Previc