Isn't our genetic legacy hardwired? From Mendel and Darwin in
the 19th century to Watson and Crick in the 20th, scientists
have shown that chromosomes passed from parent to child form a
genetic blueprint for development. But in a quiet scientific
revolution, researchers have in recent years come to realize
that genes aren't a fixed, predetermined program simply passed
from one generation to the next. Instead, genes can be turned on
and off by experiences and environment. What we eat, how much
stress we undergo, and what toxins we're exposed to can all
alter the genetic legacy we pass on to our children and even
grandchildren. In this new science of "epigenetics," researchers
are exploring how nature and nurture combine to cause behavior,
traits, and illnesses that genes alone can't explain, ranging
from sexual orientation to autism to cancer. "We were all
brought up to think the genome was it," said Rockefeller
University molecular biologist C. David Allis. "It's really been
a watershed in understanding that