The new science of Epigenetics shows that we inherit more than just family photographs, furniture, noses and hair-lines from our ancestors. Many acquired characteristics, behavioral traits, and specific physiological responses can be traced back generations, even to our great-great grandparents. Both the inherited traits and the early learning that shape us are firmly rooted in methylations and acetylations, many other tags and switches, too, that incorporate sets of genes. We inherit some traits, not from genes of our DNA, but from distinctive conglomerations of millions of molecular attachments onto the heterochromatin complexes along our 46 chromosomes, each a combination of DNA and histone proteins. The result, your brain evolves itself.
Our brains contain one hundred billion nerve cells (neurons). Each neuron makes links with ten thousand other neurons to form an incredible three dimensional grid. This grid therefore contains a thousand trillion connections - that's 1,000,000,000,000,000 (a quadrillion). It's hard to imagine this, so let's visualise each connection as a disc that's 1mm thick. Stack up the quadrillion discs on top of each other and they will reach the sun (which is ninety-three million miles from the earth) and back, three times over.
Nessa Carey, The Epigenetics Revolution
It now appears that if, generation after generation, a particular trait or acquired characteristic maintains its value, that beneficial trait becomes increasingly indelible. At some point, that acquired trait carried by our histone proteins becomes really acquired as a permanent fixture – as a functional gene on our DNA. That functional transition may not be well-defined, but forever transient. This mechanism for transition from epigenetic modifications to genes represents a fast-track for evolution, an underlying mechanism for rapidly acquired adaptations, a mechanism quite distinct from natural selection.
In a 2007 Yale study, babies just a few months old demonstrated a clear sense of right and wrong at three months of age. “Humans are born with a hard-wired morality, a sense of good and evil is bred in the bone,” says Paul Bloom, author of Just Babies: The Origins of Good and Evil. Three-month-old babies exhibit early signs of adult traits, showing an overwhelming preference for “good babies” over “bad babies.” Researchers found evidence for developing characteristics such as altruism, empathy, confluence, and curiosity. Babies develop social networks right away, mostly based on “sameness.” (what might be called “bigotry”?) Such characteristics are cross-cultural and often accompanied by displays of territoriality, aggression, and violence even in the best of babies. All this, well before they could be taught by parents or influenced by peers. Where, if not the epigenome, do all these traits come from? Just a few years later, some children show prodigious talents in music, math, and art as soon as they develop the motor skills to perform such things, and well before lessons.
By the time we’re adolescents we’ve established clubs, cliques, uniforms, and taboos. As adults we make lists of Do’s and Don’ts, like The Ten Commandments, The Koran (or Quran), or The Seven Deadly Sins. It’s only human – from downtown Des Moines to highlands of Papua New Guinea. Everything from facial expressions to emotional responses to sex drives appear instinctual too, influenced by culture, but springing forth naturally and recognized worldwide, even in the most remote villages.