Our community rightly spends a good deal of time pointing out errors in media stories about autism, but it’s so much more enjoyable to write about mainstream articles which get the scientific issues involved in autism right.
The cover story in TIME magazine last week is entitled “Why Your DNA Isn’t Your Destiny” (HERE) by John Cloud. I was amazed at what a great job the writer did with a very complicated subject. And yes, it touches on autism.
As somebody who teaches both genetics and evolution these are important matters, not just in the great span of time, but also in our individual lives. Before I get into the subject of epigenetics let me give you a little background on evolution in general and genetics in particular.
In the 150 years since Darwin published On the Origin of Species the controlling belief was that your genes were your destiny. The good genes conveyed a survival advantage that would persist over time, while those that didn’t would be weeded out. You could pretty much do whatever you wanted to yourself, drink or smoke yourself into an early grave, but when your kids were born they got a blank slate when it came to their genetics. They’d have the same chance as you did. The sins, health habits or environmental exposures of the parent did not pass onto the children.
But the evidence showed something radically different from this view of evolution. For example, what were the effects of periods of feast and famine on the descendants of those who survived? Using data from an area of northern Sweden, scientists were able to determine how much food had been available to selected subjects and various times in their development.
The research showed that boys who went from normal eating to gluttony in a single season turned out to have grandsons with a decreased life expectancy (adjusting for socio-economic factors) of 32 years! Think of that! Your grandfather’s eating habits might determine whether you live to be 84 or 52 years old. This is not what Darwin would have predicted. But science always changes in response to new information.
The article went on to cite other examples of how an environmental exposure may have long-lasting health effects. One epigenetic study suggested that the rise in peanut allergies may be explained by the new use of peanut oils in baby lotion formulas. Another study showed “fruit flies exposed to a drug called geldamamycin showed unusual outgrowths on their eyes that can last through at least 13 generation of offspring even though no change in DNA has occurred (and generations 2 through 13 were not directly exposed to the drug.)” Another recent publication in this field cataloged “some 100 forms of epigenetic inheritance.”
Then there was this paragraph which went to the heart of the issue: “More recently, however, researchers began to realize that epigenetics could also help explain certain scientific mysteries that traditional genetics never could; for instance, why one member of a pair of identical twins can develop bipolar disorder or asthma even though the other is fine. Or why autism strikes boys four times as often as girls . . . In these cases, the genes may be the same, but their patterns of expression have clearly been tweaked.”
The epigenome is then best understood as existing above your genes (or genome), but influencing how your genes work. The explanation offered by biologists is that if your genome can be compared to a computer’s hardware, the epigenome is the software telling it how to function. The process of changing the genome is through a process called DNA methylation; a single carbon atom attached to three hydrogen atoms. “When a methyl group attaches to a specific spot on a gene . . . it can change the gene’s expression, turning it off or on, dampening it or making it louder.”
All of which brings us back to autism.
Our community has long asserted our children were not genetically pre-determined to get autism. If autism was purely a genetic problem then the numbers should be 1 in 100 from here until the dawn of time. The autistic should be part of our culture, the stories we tell, the very fabric of our society. But they’re not. Instead we have stories about the tidal wave of adults with autism we can expect in the next few years and how poorly prepared we are for them. Nobody saw this problem until it was first described in the 1940s. From that time it’s gone from 1 in 10,000 to 1 in 100. With that rate of increase, can it be long until it goes to 1 in 10? We need to find answers.
And let’s be clear about it. Most of us saw a change after a vaccination, a procedure which has become more common since our generation (10 vaccinations in the 1980’s before the age of 5 to 36 vaccinations under the current schedule) and has been administered at earlier ages.
Many of the far-sighted researchers and physicians in autism have been talking about DNA methylation for years. These concerns have finally begun to enter the mainstream conversation.
Science is showing that a change in eating patterns can have consequences that reach down the generations. Peanut oil in baby lotions might be behind the amazing rise in peanut allergies. A drug administered to a fly affects thirteen succeeding generations. What has the increased vaccination schedule done to our children? What might a single vaccination do to the genome of a child, or even an adult?
These are reasonable questions and I’m glad a magazine like TIME is coming close to asking them. That’s what science is about. Asking the right questions and getting meaningful answers which can help people. This needs to happen in autism.
I hope the rest of the media follows TIME magazine’s excellent example.
Kent Heckenlively is Contributing Editor of Age of Autism