28 July 2005
Autism, Asperger's and Evolution
By Rusty Rockets
What is the difference between a genetic abnormality and genetic evolution? Is the human body's adaptability responsible for many of the conditions that we call mental disorders? Researchers concede that the science world is still in the dark about the causes of autism and asperger's disorder, but they also concede that autism and asperger's are most likely genetically oriented. Is it possible that in disorders such as autism and Asperger's we are witnessing evolution at work?
"From my clinical experience I consider that children and adults with Asperger's Syndrome have a different, not defective, way of thinking," says Tony Attwood, a clinical psychologist at Griffith University and author of Asperger's syndrome: A Guide for Parents and Professionals. We all have a different perspective on the world from the person sitting next to us, so perhaps autism and Asperger's are just relative extremes to the much more prevalent mild differences of individual perspective. The information that bombards our brains everyday is analyzed, processed and scrutinized until we arrive at a consistent model of the world that allows us to cope with everyday life. How this happens must rely heavily on how our brains are constructed and how our genes and DNA sequencing determine our final brain composition during embryo development.
Interestingly, Richard Dawkins considers DNA-as-blueprint to be a bad analogy, claiming that using origami provides a much better one. "The main organization of the body is initially laid down by a series of foldings and invaginations of layer cells. Once the main body plan is safely in place, later stages in development consist largely of growth, as if the embryo were being inflated, in all its parts, like a balloon," says Dawkins. Unlike most balloons, however, "different parts of the body inflate at different rates, the rates being carefully controlled," Dawkins adds. The important point here is that cells know what to do in reference to adjacent cells. Dawkins claims that cells attract, repel, change shape, die and even secrete chemicals that may affect neighboring cells. "All cells contain the same genes," says Dawkins, "so it can't be their genes that distinguish cell behavior. What does distinguish a cell is which of the genes are turned on. Which usually is reflected in the gene products - proteins - that it contains."
This leaves a lot of scope for variation in individual people, and perhaps external factors affect how genes turn on and off during this embryonic phase. Dawkins says that certain social and environmental conditions play an influential role in how the gene pool is divided. Religion, language, geographical location and social customs all ensure that mating is not just a random process. "I am suggesting that human culture has done very odd things to our genetics in the past," says Dawkins. However, Dawkins also claims that taking the totality of our genes into account "we are a very uniform species," and that these so called differences are mostly superfluous.
Recent studies show that autism and Asperger's are not similar to those gene anomalies that Dawkins describes. Evidence is mounting to support suspicions that autism has genetic roots, and it is not peculiar to specific locales determined by culture or geography and is blind to cultural specifics.
Interestingly, Matt Ridley, author of Nature via Nurture, claims that those with Asperger's disorder: "are more than twice as likely to have fathers and grandfathers who worked in engineering." Ridley also says that on a "standard test of autistic tendencies, scientists generally score higher than non-scientists and physicists and engineers score higher than biologists." Collectively, various experts claim that the prevalence of autism or autistic disorder is 1:1000, and Asperger's disorder at anywhere from 1:150 to 1:500, depending on what you read. That's quite a high figure, and it doesn't include those who fit somewhere in between. On the face of it, then, we are looking at a society that has a full spectrum of ways of seeing and interpreting the world, and these perspectives and abilities might be passed on to our progeny.
A study conducted by the Mount Sinai School of Medicine, published in the American Journal of Psychiatry, claimed that no single gene produces Asperger's disorder. Rather, the commonly accepted model states that it is a result of the accumulation of between five-to-ten genetic mutations. "Having one of these variants appears to approximately double an individuals risk for the disorder, but it is an accumulation of genetic factors that cause the disease," said Joseph Buxbaum, Associate Professor of Psychiatry at Mount Sinai School of Medicine. "Identifying all or most of the genes involved will lead to new diagnostic tools and new approaches to treatment," Buxbaum added. Considering that the disorder affects so many parts of a person's mental composition, any treatment for autism or Asperger's may also change the person's personality in fundamental ways; a point that researchers and medical practitioners might want to think about. Consider this statement from Jim Sinclair, who holds a BA in psychology, has autism himself, and also advocates for those with autistic disorder: "Autism isn't something a person has, or a shell that a person is trapped inside. There's no normal child hidden behind the autism. Autism is a way of being. It is pervasive; it colors every experience, every sensation, perception, thought, emotion and encounter - every aspect of existence. It is not possible to separate the autism from the person - and if it were possible, the person you'd have left would not be the same person you started with."
Conditions such as autism and Asperger's raise controversial questions on normalcy in society. If autism is proved conclusively to be biological, there is consequently nothing about autism that can be "cured", without also changing the person in fundamental ways. But what is normal is also a moot point, and it seems that society and culture have a larger role to play in that respect. Describing the characteristics of certain animal survival techniques, Dawkins says that the "brain needs to construct a mental model of a three dimensional world." All of these world models are constructed via different attributes like a keen sense of smell or sonar. Could certain conditions that we call "disorders" really be evolution at work?