Autism and Human Atavism

Please read this post if you are offended by the contents of this blog. at·a·vism [at-uh-viz-uhm] (noun) the reappearance in an individual of characteristics of some remote ancestor that have been absent in intervening generations. From "Hominins and the Emergence of the Modern Human Brain" (Published Jan 2012):     "Autism...is referenced in studies of fossil hominin brain structure and function, either as an analogy for developmental differences between closely related species or as a potentially atavistic indication of actual primitive phenotypes. For example, an autistic child lacking language created naturalistic artwork much like that from the Upper Paleolithic, on the basis of which it was suggested that fAMHS could have also lacked fully modern cognition" Autism: The Eusocial Hominid Hypothesis:      ASDs (autism spectrum disorders) are hypothesized as one of many adaptive human cognitive variations that have been maintained in modern populations via multiple genetic and epigenetic mechanisms. Introgression from "archaic" hominids (adapted for less demanding social environments) is conjectured as the source of initial intraspecific heterogeneity because strict inclusive fitness does not adequately model the evolution of distinct, copy-number sensitive phenotypes within a freely reproducing population.      Evidence is given of divergent encephalization and brain organization in the Neanderthal (including a ~1520 cc cranial capacity, larger than that of modern humans) to explain the origin of the autism subgroup characterized by abnormal brain growth.      Autism and immune dysfunction are frequently comorbid. This supports an admixture model in light of the recent discovery that MHC alleles (genes linked to immune function, mate selection, neuronal "pruning," etc.) found in most modern human populations come from "archaic" hominids.      Mitochondrial dysfunction, differential fetal androgen exposure, lung abnormalities, and hypomethylation/CNV due to hybridization are also presented as evidence.

[autismandhumanatavism]

The major genetic risk factor for severe COVID-19 is inherited from Neanderthals

Risk of severe COVID-19 is conferred by a genomic segment that is inherited from Neanderthals and is carried by around 50% and 16% of people

Could autism spectrum disorders be a risk factor for COVID-19?

The coronavirus SARS-CoV-2 pandemia is infecting millions of people and some studies relate conditions that might increase the risk of devel

@slatestarscratchpad

[slatestarscratchpad]

I think I’ve finally figured out the “why are there so many transwomen in the rationalist community”? question.

This site claims:

There is the curious statistic that while transkids have as a group, average IQ=100, non-homosexual transsexuals exhibit, as a group, significantly higher IQ (127.9 in one clinical study), very unlikely to have happened by chance. 

As far as I know most of the transwomen in our community are lesbians, and I think their “non-homosexual” thing is relative to assigned gender at birth, so I think we’re talking about the same demographic.

Average IQ in the rationalist community is 140 as per the survey. If we use our handy Normal Distribution Calculator, we find that about 21% of transwomen should have IQ 140 or above, compared to about 0.5% of cis people. So about 40x more transwomen should reach that IQ cutoff than cis people.

People keep saying the US is something like 0.3% trans. Depending on how low an estimate that is and how many of those people are the non-homosexual transsexuals the study is talking about, we can estimate that maybe like 5-10% of the community should be transgender, which is more or less what the survey found.

Also, whoa. If this is true, being transgender is the highest IQ boost of anything I know including the really awful things like torsion dystonia. The site theorizes that this is because only very high-IQ people have the financial/social resources to deal with transitioning, but that doesn’t make sense - only 3% of people have that IQ naturally, so that would have to mean that for every open transwoman there are 30 or so who want to transition but are still in the closet even if IQ mapped perfectly to level of resources which of course it doesn’t.

[autismandhumanatavism]

Saving this.

[slatestarscratchpad]

Is there such a thing as a reliable source of information and investment advice about cryptocurrencies? Aren't there any prediction markets on Bitcoin's exchange rate and related dynamics?

I think the value of publicly-traded financial instruments is a prediction market.

[autismandhumanatavism]

What about when people divest from stuff they predict will do well, but they don’t want to do well? Is the fact that you can’t enter the market without affecting it crucial to the predictive usefulness? Maybe that’s why PM experiments decoupled from actual investment can have mixed results.

[autismandhumanatavism]

The three parent taxa in our analysis represent lineages that diverged over approximately the same period as the human/Neanderthal/Denisovan lineages and their hybrids are variably successful in the wild. Comparisons of body size, as quantified by long bone measurements, are also presented to determine whether the identified phenotypic effects of hybridization are localized to the cranium or represent overall body size changes. The results indicate that hybrid cranial and mandibular sizes, as well as limb length, exceed that of the parent taxa in all cases. All three F1 hybrid crosses display similar patterns of size and form variation. These results are generally consistent with earlier studies on primates and other mammals, suggesting that the effects of hybridization may be similar across very different scenarios of hybridization, including different levels of hybrid fitness. This paper serves to supplement previous studies aimed at identifying F1 hybrids in the fossil record and to introduce further research that will explore hybrid morphologies using mice as a proxy for better understanding hybridization in the hominin fossil record.

Craniomandibular form and body size variation of first generation mouse hybrids: A model for hominin hybridization

[slatestarscratchpad]

I can't get over how many technical terms are thrown around while you clearly have a very inaccurate, and stereotypical, understanding of autism and schizophrenia. This is as detrimental as the "extreme male brain" BS. I wish people would stop throwing around ignorant "theories".

I am sorry that the two biology professors, multiple published studies, New Scientist article, positive reviews of the theory in the British Journal of Psychiatry, PNAS, and Psychological Review, and other sources that I checked are all so stupid. Clearly I should have checked with more reliable sources, like abusive Tumblr anons who don’t justify their opinions.

I am sorry that I understand autism at the same sort of naive pop science level as eg Temple Grandin (who endorses the diametrical theory).

Most of all, I am sorry that my article only included the caveats “I’ve previously been skeptical of this kind of thinking”, “Is this true? There’s not great evidence for it”, “I know a lot of people who combine excellent technical skills with excellent social skills”, “there are many things that autists and schizophrenics have in common”, “The best that can be said about this theory is that it would be a really neat way to explain the patterns of similarities and differences”,and a couple of others.

I am glad I have people willing to set me right about these kinds of things.

[slatestarscratchpad]

Today I learned: there is Mongolian folk rock, and it is exactly what you would expect:

[autismandhumanatavism]

[kontextmaschine]

Do you believe that curing death or mastering cryonics will happen within your natural lifetime?

No. Immortality has been “just a few improvements on the current state of the art” away for approximately ever.

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Don’t tell the most recent immortality cult about this. It would break their clichéd little hearts.

[kontextmaschine]

Yeah the funny thing is how the “state of the art” consistently refers to whatever field’s particularly prominent and cutting-edge at the time.

It’s been alchemy in medieval Europe and ancient China, electricity in Revolutionary France, extremely low-temperature liquid circulation in the rocket age, data storage in the computer age, now it’s biotech because of course it is.

In 16th Century Spain with the whole Fountain of Life thing it was fucking western hemisphere cartography.

[prudencepaccard]

“In 16th Century Spain with the whole Fountain of Life thing it was fucking western hemisphere cartography” holy shit this is 100% right

[shlevy]

Ya know, I’m super skeptical of any indefinite life extension or cryonics being viable any time soon, and I’m generally really annoyed by scientism, but there’s a bit of a difference between “drink random potions”, “shock yourself”, “follow biblical literalism” on the one hand and fucking “continue advancing medical science” on the other.

[slatestarscratchpad]

Ha ha, look at all those idiots who thought that just because they knew a little science they could ever extend something as mystically untouchable as human lifespan, they’re exactly as stupid as alchemists and people who believe in the Fountain of…

(”But that’s mostly just curing infectious diseases! Going up against the Gompertz limit itself is a totally different game!”)

(Huh, sounds like you think we know a lot about this problem and are pretty sure science applies to it. Are you sure you’re not just saying something stupid, like an alchemist inventing a list of exactly which ailments the Philosophers’ Stone could or couldn’t cure?)

[autismandhumanatavism]

We'll see.

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They found hundreds of regions throughout the human genome which showed a markedly different chromatin structure in neurons in the prefrontal cortex, a brain region that controls complex emotional and cognitive behavior, compared to non-human primates. The findings of the study provide important insights for diseases that are unique to humans such as Alzheimer’s disease and autism. “While mapping the human genome has taught us a great deal about human biology, the emerging field of epigenomics may help us identify previously overlooked or discarded sequences that are key to understanding disease,” said Dr. Akbarian. “We identified hundreds of loci that represent untapped areas of study that may have therapeutic potential.” Dr. Akbarian and his research team isolated small snippets of chromatin fibers from the prefrontal cortex. Next, they analyzed these snippets to determine what genetic signals they were expressing. Many of the sequences with human-specific epigenetic characteristics were, until recently, considered to be “junk DNA” with no particular function. Now, they present new leads on how the human brain has evolved, and a starting point for studying neurological diseases. For example, the sequence of DPP10—a gene critically important for normal human brain development—not only showed distinct human-specific chromatin structures different from other primate brains such as the chimpanzee or the macaque, but the underlying DNA sequence showed some interesting differences from two extinct primates—the Neanderthal and Denisovan, most closely related to our own species and also referred to as ‘archaic hominins’.

Short DNA Strands in the Genome May be Key to Understanding Human Cognition and Diseases - Mount Sinai School of Medicine (via slartibartfastibast)

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The two researchers, Vernot and Akey, also found that whilst each individual may only have 1-3% Neanderthal, when combined humans have a whopping 30% of the Neanderthal genome in them. Albeit spread out into lots of little pieces, almost like we’re torrenting their genome…They also found that this spread of genes couldn’t be explained by one bout of interbreeding between us and Neanderthals. There had to have been at least 2: one before Europeans and East Asians became different populations, and one in East Asians just after they did.

Neanderthal genes helped humans adapt | EvoAnth (via slartibartfastibast)

Gee, I wonder if the adaptive phenotypic variations found within small neandertal groups ended up reoccurring at larger scales in introgressed populations, allowing gigantic eusocial societies to form.

(via slartibartfastibast)

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In primates, there tend to be genes that have only DUF1220 on them and nothing else — sometimes as many as 50 in one gene. Whatever it’s doing, it seems important. The most obvious thing to check first is brain size. And sure enough, this rapid increase in DUF1220 copy number has a very strong correlation with both the overall brain size and cortical neuron count in primates, but not with body size. This became even more interesting when researchers sequenced the Neanderthal. Neanderthals are thought to have had larger brains than modern humans, based on skull size. Coincidentally, they also appear to have had ~300 DUF1220 domains. So researchers began to look for correlations within the human species, and found some. The number of DUF1220s correlates strongly with “cognitive function” (based on total IQ and mathematical aptitude tests), but also with the severity of autism (though it doesn’t seem to actually cause autism). And now, DUF1220 copy number has been linked to schizophrenia, fueling the idea that autism and schizophrenia are diametrically opposed diseases.

inverse.com (1/18/16)

Stan Gooch called this in the 70s (especially that last sentence) and then died alone in a trailer about a year after Paabo published the first neanderthal genome.

(via slartibartfastibast)

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ASD has been characterized in terms of a hyper-modular mind (Kenett et al., 2015) that lacks the cognitive flexibility observed in non-affected people. Interestingly, the Neanderthals mind has been described as a conglomerate of specialized intelligences lacking the cognitive flexibility of AMHs (Mithen, 1996, 2005). All of this does not suggest that ASD is an atavistic trait. However, the study of the etiopathogenesis of ASD (including candidate genes and abnormal brain rhythms) may benefit from ongoing studies of language evolution in the species (and vice versa). Recent research has linked the emergence of complex, highly prevalent conditions like ASD to the uncovering of cryptic genetic variation resulting from our evolutionary history (Gibson, 2009).

The Oscillopathic Nature of Language Deficits in Autism: From Genes to Language Evolution (4/20/16)

PSSSSSSSST

(via slartibartfastibast)

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The research team found that not only was DUF1220 linked to severity of autism overall, they found that as DUF1220 copy number increased, the severity of each of three main symptoms of the disorder — social deficits, communicative impairments and repetitive behaviors — became progressively worse.

Gene family linked to brain evolution implicated in severity of autism symptoms (x, y)

yikes, that’s a notable discovery is it not?

(via argumate)

@ilzolende

(via wirehead-wannabe)

> Strikingly, Davis says, DUF1220 is as common in people who do not have ASD as in people who do. So the link with severity is only in people who have the disorder.

It’s not a good prenatal test, guys. [turns off alarm]

(via ilzolende)

Yeah, neanderthal DNA (or just non-sapiens stuff in general, because sapiens were the most social hominid) plus environmental insult seems to be diagnosed as autism.

(via slartibartfastibast)

[autismandhumanatavism]

Given multiple origins of eusociality in Hymenoptera (bees, ants, and wasps), it has been proposed that insect castes evolved from common genetic “toolkits” consisting of deeply conserved genes. Here, we combine data from previously published studies on fire ants and honey bees with new data for Polistes metricus paper wasps to assess the toolkit idea by presenting the first comparative transcriptome-wide analysis of caste determination among three major hymenopteran social lineages. Overall, we found few shared caste differentially expressed transcripts across the three social lineages. However, there is substantially more overlap at the levels of pathways and biological functions. Thus, there are shared elements but not on the level of specific genes. Instead, the toolkit appears to be relatively “loose,” that is, different lineages show convergent molecular evolution involving similar metabolic pathways and molecular functions but not the exact same genes. Additionally, our paper wasp data do not support a complementary hypothesis that “novel” taxonomically restricted genes are related to caste differences.

Comparative Transcriptomics of Convergent Evolution: Different Genes but Conserved Pathways Underlie Caste Phenotypes across Lineages of Eusocial Insects

[autismandhumanatavism]

Hybridization has been considered an evolutionary dead end, but its evolutionary significance is becoming more widely recognized. Hybridization is associated with a reproductive tradeoff. Eusocial organisms, such as ants, characterized by a reproductive division of labor, may be able to overcome this tradeoff. Examples of hybridization in ants are common in the literature, but surprisingly few studies investigate its adaptive significance. I investigated the interplay between hybridization and eusociality in a fire ant hybrid zone between Solenopsis xyloni and S. geminata. First, I investigated if mechanisms generating genetic differences between the worker and reproductive castes are environmentally or genetically based in colonies S. xyloni in the hybrid zone. I fostered queens collected from inside the hybrid zone and in allopatry with either pure species or hybrid workers, recording the proportion of queens that produced worker offspring. I found that the proportion of queens producing workers was not significantly different when queens with fostered with hybrid or S. xyloni workers; only offspring paternity predicted worker production. Solenopsis xyloni queens in the hybrid zone mated to their own species of male did not produce worker offspring in any context, suggesting that in the hybrid zone offspring caste determination is genetically fixed. This may represent the strongest case of genetic caste determination yet described, and it may have arisen because of conditions in the hybrid zone. Second, I tested if hybrid workers were associated with advantages in the ecologically relevant traits of foraging and competitive ability. Colony fragments foraged for bait, and then colony pairs were allowed to compete for food and territory. The parental species, S. xyloni adapted to desert, and S. geminata adapted to savanna habitats, were more efficient at foraging and competition, respectively; hybrids were largely intermediate. This suggests that the parental species are specialized on opposite aspects of a discovery/dominance tradeoff, which may underlie the coexistence and exclusion of parents and hybrids inside and out of the hybrid zone. Solenopsis xyloni queens in the hybrid zone only occur with hybrid workers, suggesting the intermediate behavioral strategy of hybrids may be selectively advantageous in the hybrid zone. Finally, I reconstructed phylogeographic relationships and evaluated genetic diversity in S. geminata to assess the timeframe of range expansions into the hybrid zone. I found that S. geminata is likely to have arisen in Mesoamerica, and appears to have had made several historical expansions from Mesoamerica into its current geographic distribution. One such expansion northward into what is presently the hybrid zone in Mexico and Texas, likely occurred 2.4-3.76 million years ago. This timeframe suggests that the hybrid zone may have persisteq over several million years, and the unique reproductive strategy found in S. xyloni may be evolutionarily stable. Overall these studies suggest that eusocial organisms can reduce the reproductive costs associated with hybridization and may overcome the reproductive tradeoff; hybrids can be associated with non-reproductive advantages, suggesting hybridization may be important in evolutionary processes, and hybridization has resulted in a unusual form of caste determination in the hybrid zone, implying that understanding the interplay between hybridization and eusociality are important in understanding biological' complexity

Interplay between eusociality and hybridization in a fire ant hybrid zone