Guest Author Dawson Church on DNA, Genes and More
As part of his virtual tour to promote his book, I decided to question Mr. Church on some subjects relevant to his work and curious to me.
S: For a long time it was thought that individuals are the result of their genes. Before the Human Genome study it was presumed that the DNA of humans would be complex, vastly more so than say, a mouse. Did this finding kick off the epigenetics theory or was it more a matter of bringing back into attention something from earlier times?
DC: It was eye-opening when the Human Genome Project showed that humans share about 99% of the genes of mice. We have only about twice the number of genes found in a simple insect such as a fruit fly. Scientific papers from the early 1990s spoke of over 100,000 genes. A decade later scientists were talking 65,000 genes, then 40,000, down to the current consensus of 23,688 genes. These findings told us that epigenetics, control of the DNA from outside the genome, was very important in differentiating human bodies.
S: Some time back there was a study that looked at the environments of grandmothers and how this affected their children and the children of their children. Was this the beginning of a real look at the effects of environment on DNA expression?
DC: A number of provocative studies have shown that love and nurturing is epigenetic. When we’re loved, gene switches in the stress-response parts of our brain are tripped, and these changes affect our lives. They can also be passed on to the next generation. So the offspring of nurturing parents tend to nurture their young better, several generations on. All this without any change in the DNA sequence!
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