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Autism and Evolution
51–60 of 91 posts
Re: Autism and Evolution
#52There have been instances of biological twins where one winds up with autism and another doesn't. So to the extent that autism has a genetic component - it is just that - a component.
That does support non-genetic factors to some extent, but the existence of such twins matters less than their frequency, because twins don't always have identical DNA (mutations can occur after they separate).
Also, even with identical DNA, that doesn't mean the twins will be exactly identical: if things like fingerprints are only very similar instead of exactly matching, then there's reason to think that the fine brain structure can vary as well -- perhaps enough to straddle sides of a disorder.
So in addition to twin frequency, it would be worth analyzing twin spread: what is the variation in the behavior of twins (in the background), and is the spread in autistic/non-autistic twin pairs statistically similar, ie, are we just selecting for normal, expected variation that happens to fall close to a boundary?
Re: Autism and Evolution
#53Earlier quoted context omitted.
(not the person you're replying to) The implication seems to be that the parents also exhibit traits of the autism spectrum, so it's hardly surprising that their kids would do the same.
If it's that, without finer detail, it's also a weak argument. I behave like my mother in many things; doesn't mean I was genetically predisposed to, as plenty of behavior is acquired from the parents.
"Inherited" can mean "genetic" or some other method of parent-child transmission (like learning)
"Environmental" can include "parenting", but in this case the distinction is between "got it somehow from autistic-leaning parents" vs got from something else.
Also, the claim that autism might be somehow learned from parents is extraordinary and not widely claimed or supported by existing evidence. It was a discredited theory of the past though, that "cold" parenting created austism.
Re: Autism and Evolution
#54I don't quite buy that autism will be shown to be genetic. I think it's an environmental factor. The rate of increase in autism is pretty much exponential: http://www.nature.com/news/2011/111102/full/479022a/box/1.ht... Now that's a very scary chart if you start to project that curve into the future. Here's another one. Not saying this is the cause, but it is a cause for concern. We have many similar patterns of envi…
My cousin had debilitating autism that was greatly diminished by removing wheat germ from his diet, so I partially buy the environmental take, but on the other hand it is a disease that is correlated with parental IQ, where a higher IQ leads to more likely incidence of autism. I don't think it's a coincidence that the rise of co-sexed secondary education and finer grained sorting with institutions like Harvard and MI…
In a child with autism, pain becomes debilitating because they can't communicate or cope with pain well. That doesn't mean an allergy or intolerance causes autism, however.
An allergy or intolerance is much worse when it make your nonverbal child irritable and violent, then when it makes your verbal child say "mom, my tummy hurts bad" after you serve pizza.
Re: Autism and Evolution
#55Earlier quoted context omitted.
Since this thread is about evolution, we might even say that the evolutionary pressures we currently face in the developed world actually favor mild variants of ASD. It might be because some ASD traits help people become more successful in the information economy. Asperger's people often thrive in well-paid occupations such as programming and data analysis where spontaneous social interaction is widely acknowledged t…
I have not seen any evidence that Asperger Syndrome or mild autism leads to well-paid occupations. For sure, there is some anecdotal evidence (which I find unconvincing), but I haven't come across anything more solid, like a research paper or study. If you've seen something along those lines, please post a link. I do believe that children with Asperger Syndrome often see the symptoms grow less severe as they age. Per…
What appears to be Aspergers now is very similar to spending lots of time on the Internet and then trying to interact socially afterwards. It's quite difficult to appear neuro-typical after a surfing session, and for today's kids, Aspergers is the 'New Normal'. Aspergers was even taken off the DSM-5: http://www.slate.com/articles/health_and_science/medical_exa...
Re: Autism and Evolution
#56I don't quite buy that autism will be shown to be genetic. I think it's an environmental factor. The rate of increase in autism is pretty much exponential: http://www.nature.com/news/2011/111102/full/479022a/box/1.ht... Now that's a very scary chart if you start to project that curve into the future. Here's another one. Not saying this is the cause, but it is a cause for concern. We have many similar patterns of envi…
I'd strongly recommend you listen to Steve Silberman, Neurotribes author, on Fresh Air: http://www.npr.org/sections/health-shots/2015/09/02/43674237... (Audio controls in the left margin.) He addresses that a fair bit, mentioning that autism is one of the most heritable conditions, and talking a lot about the history of the diagnosis and how it was artificially narrow for a long time. Personally, my bet is that we'll…
When are we going to finally ditch the idea that heritable==genetic?
Re: Autism and Evolution
#57So are Asperger / ASD mutations, a step back, step forward, or a step in a different direction (evolution?)
dragonwriter is right in general sense. We can evaluate it, though, from our own perspective. It's a step forward in terms of intelligence and stability in world. It's a giant leap backward in terms of success or happiness in a world of non-autistic people. Evolution would also consider it a negative in that autistics get laid and reproduce less than non-autistics. They also are more likely to loose in competition in…
There's a lot of rampant speculation in the comment here.
Re: Autism and Evolution
#58Earlier quoted context omitted.
My cousin had debilitating autism that was greatly diminished by removing wheat germ from his diet, so I partially buy the environmental take, but on the other hand it is a disease that is correlated with parental IQ, where a higher IQ leads to more likely incidence of autism. I don't think it's a coincidence that the rise of co-sexed secondary education and finer grained sorting with institutions like Harvard and MI…
In a child with autism, pain becomes debilitating because they can't communicate or cope with pain well. That doesn't mean an allergy or intolerance causes autism, however. An allergy or intolerance is much worse when it make your nonverbal child irritable and violent, then when it makes your verbal child say "mom, my tummy hurts bad" after you serve pizza.
Now that he's verbal he can describe what it felt like: He was completely off his ass baked. Just high as a kite. Unable to focus he was so high.
Re: Autism and Evolution
#59Earlier quoted context omitted.
I'd strongly recommend you listen to Steve Silberman, Neurotribes author, on Fresh Air: http://www.npr.org/sections/health-shots/2015/09/02/43674237... (Audio controls in the left margin.) He addresses that a fair bit, mentioning that autism is one of the most heritable conditions, and talking a lot about the history of the diagnosis and how it was artificially narrow for a long time. Personally, my bet is that we'll…
When are we going to finally ditch the idea that heritable==genetic?
>>When are we going to finally ditch the idea that heritable==genetic?
Well, considering the fact that "heritability" is a measure of how much of a given phenotype's expression is due to genetic variation, probably not soon. "Heritable" is not a word used to refer to environmental factors such as parental care and upbringing. In studies on heritability of specific traits, these environmental factors are used as classifications for broader observations of genetic variations (for example, in twin studies, was twin pair A raised in the same household like pair B?).
Going back to autism specifically, the Simons Foundation Autism Research Initiative identified a single genetic mutation that accounted for 25% of diagnoses in their Simplex Collection[1], while the other 75% were impacted by 200-400 different genes. This data is available online as of 2016[2], though some analyses may be paywalled.
[1]: https://sfari.org/resources/autism-cohorts/simons-simplex-co...
[2]: https://www.simonsfoundation.org/features/foundation-news/si...
Re: Autism and Evolution
#60There have been instances of biological twins where one winds up with autism and another doesn't. So to the extent that autism has a genetic component - it is just that - a component.
you mean "identical". both identical twins and fraternal twins are biological twins.