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Toxn

Human genetics

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I'm going to post a few things from Razib Khan, who I have a strange affection for*:

https://gnxp.nofe.me/article/58961bef5394dc4880000028

https://gnxp.nofe.me/article/58916d2f5394dc2f2e00000a

https://gnxp.nofe.me/article/5890eb382fab740d79000003

https://gnxp.nofe.me/article/5890eae32fab740d30000001

The last one should be understood in the context of a study which found that roughly half of our genome could be linked to IQ in some way. Educational achievement in the UK, it seems, is very much less polygenic than IQ. Of course, it could also be a confounder of some kind - the UK has a genetically stable population (lineages haven't moved around all that much geographically for hundreds of years), which opens up the possibility of linkage between geographical distribution of educational opportunity, inherited social classes and so on. But certainly interesting in terms of one side of a debate that I'm very much on the other side of. I'm interested to see if it holds.

 

 

 

* 'Strange' because I find that I like his writing about genetics but almost nothing else about him. Not that he's a bad human being or anything, just a personal preference thing.

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I'd have to check, but my understanding is that it's still the same as before: hard positive selection on populations which domesticated milk-bearing animals. So there are several origin sites of lactase persistance corresponding with sites of domestication/adoption, and the spread through those populations corresponds with time.

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Genes and homonims, so I'm putting this here:

http://www.bbc.co.uk/news/science-environment-39205530

Neanderthals chewed poplar bark, possibly for pain relief, and had penicillin in their mouths. Maybe pushing back human antibiotic use (probably to treat a viral infection) for thousands of years, or pushing back the timeline for mouldy bread for a couple of thousand less years. Full nature article here, behind the paywall:

http://www.nature.com/nature/journal/vaop/ncurrent/full/nature21674.html

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Razib lays out his views on the cultural/genetic hypotheses of human civilization:

http://gnxp.nofe.me/2017/04/23/the-logic-of-human-destiny-was-inevitable-1-million-years-ago/?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+RazibKhansTotalFeed+(Razib+Khan's+total+feed)

 

I have to stop here and note that our brains seem to be locked into an escalating arms race driven by a self-reinforcing feedback loop of some sort. This, along with the idea that the most human cognition is reserved for gaming out the behaviour of others (which seems to be as much a fitness-improving trait today as it was when we lived in small tribes) seems to support the idea that once the trigger is pulled you should see something like this effect take place with any species.

 

I personally subscribe to the belief that increases in overall intelligence will turn out not to be a linear process (ie: doubling EQ will less than double intelligence), but that's more an anti-singularity argument than an argument against increasing EQ trends in general. Anyway, here is more on the universal, gradual increase issue by way of scolding the uninformed.

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Dead Men do Tell Tales is a very readable, general audience book on forensic anthropology.  I highly recommend it.

 

The author mentions, en passant, that the rate of tooth decay for most people is quite uniform, so the condition of the teeth in an unidentified body is usually a reliable indicator of age.  He does go on to mention, however, that a small percentage of the human population suffers tooth decay at a much, much slower rate and that estimating the age of individuals so blessed will be off by decades.

 

Have geneticists looked into this at all, I wonder?

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On 24/02/2017 at 5:54 PM, Collimatrix said:

I am informed by reliable sources that there will be a media blitz about new discoveries related to Homo naledi in about one to two weeks.

 

Two weeks, two months, whatever

http://www.bbc.co.uk/news/science-environment-39842975

https://elife.elifesciences.org/content/6/e24231

Hominin family tree is more like a pile of spaghetti at this point. Every stage in the classic 'evolution of man' image turns out to have shared africa at the same time

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So this is going to keep coming up as sequencing and genomic studies in human populations goes forwards.

 

Long story short: intelligence seems to be very polygenic, with lots of small-effect genes and basically no large ones. I think the latest study tied variation in IQ in a large, wholly european population down to something like half the coding portion of the genome.

 

Which means that it is almost certain that someone is going to do a massive study into, say, melanin variants and IQ and find a statistically-significant (but miniscule) effect of some sort. Because IQ can be tied back to everything. And we are going to see trollish headlines and manufactured outrage of all sorts because of it.

 

So just mentally prep yourselves for "NEW STUDY HAS SHOCKING CONCLUSIONS!"-type headlines for the forseeable future.

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