Substack cometh, and lo it is good. (Pricing)

Open Thread – 11/22/2020 – Gene Expression

Posted on by Razib Khan

New Virgina Postrel book, The Fabric of Civilization: How Textiles Made the World.

I did an AMA and set a record for responses on the IndiaSpeaks subreddit for AMAs. probably won’t be a long record, but who knows?

How a Human Cousin Adapted to a Changing Climate.

KIR2DL4 genetic diversity in a Brazilian population sample: implications for transcription regulation and protein diversity in samples with different ancestry backgrounds. Anything on Brazilian human genetics needs to start out with a PCA plot.

We have genetic dispositions. Should we lie about this? South Asian Americans face disproportionately higher risks of heart disease, other cardiovascular ailments.

The Last Children of Down Syndrome: Prenatal testing is changing who gets born and who doesn’t. This is just the beginning. Academic Twitter loves to use the world “eugenics” in almost any context, because that’s how it rolls. But when I moot noninvasive prenatal testing there’s relative silence. The reasons are obvious.

For One Baby, Life Begins with Genome Revealed: How a California father made an end run around medicine to decode his son’s DNA. Old article about my son.

I haven’t given up on the “book club” but getting the substack up and such has put me behind the curve on a lot of things. I’ll catch up.

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15 thoughts on “Open Thread – 11/22/2020 – Gene Expression”

  1. We have genetic dispositions. Should we lie about this? South Asian Americans face disproportionately higher risks of heart disease, other cardiovascular ailments.

    I read this with interest and hoped that you would comment on it!

    I have an Indian-American friend who is a bit older than I am (late 50’s). As long as I have known him, he’s been trim and muscular and have maintained a very good fitness level and lifestyle (he eats and lives very SWPL – not traditional Indian at all). So I was pretty shocked to visit him at the hospital after a near life-threatening heart attack several years ago.

    Kinda reinforced the idea for me that, in certain avenues of life, there is only so much one can do (genetics and whatnot). The die was already cast a long time ago. It’s both humbling and a bit scary.

    Also, what is the reason for this genetic tendency toward heart problems? East Asians also don’t do well when obese (much higher likelihood of health problems at lower obesity levels than, say, whites), but East Asians tend to live long and rather robustly health-wise, provided they avoid obesity. So I can understand adaptation to low-caloric input environment, but what possible optimization led to heart issues among South Asians? If there is no definitive answer, any speculation?

  2. We have genetic dispositions. Should we lie about this? South Asian Americans face disproportionately higher risks of heart disease, other cardiovascular ailments.

    This has been well known for close to 50 years. The risk of heart attacks amongst Fijian Indians in the 1970’s and 80’s was so much higher than Angelo-Saxons in NZ it was referred to as Delhi Syndrome. The further you got from Delhi and it’s environmental contribution the higher the chance of cardiovascular disease.

    It’s not just South Asians. Pacific Islanders have even higher rates of heart disease compared to Western Europeans controlling for obesity as do Puerto Rican’s, and native Americans in the US. Variation of central body fat and insulin resistance play a role.

    Of course risk factors only get you so far. Hypertension, high cholesterol and obesity might look like a trifecta but 25% of heart attack victims have no risk factors. What works at a population level breaks down at an individual level.

  6. I just finished The Fabric of Civilization. It’s a quick read, very interesting. You hardly notice it’s sophisticated economic history/social analysis.

  7. I have heard that the current situation of high fat accumulation + low lean mass (and some other stuff that I cannot recall) in modern south Asians is a byproduct of an unfortunate genetic combination from the mixture of locals who brought one component and the steppe component that brought the other one (fat accumulation genes) along with the selection in the last 4,000 years (post IVC). I may be misremembering some of this Razib, so can you correct me if I am remembering it wrong? Doesn’t this imply that south Asians 5,000 years ago would be less likely to have problems like obesity, diabetes and heart problems than modern south Asians?

  8. DaThang, thinking from basis that Razib estimated the steppe component as like 15% (which is steppe_MLBA, about 1/3 European farmer, so the original Steppe_Eneolithic component about 10%)…

    Seems like that would imply risk gradient with groups with more steppe ancestry at high risk, and groups with low levels of steppe ancestry with very little? Or you would need a lot of selection and not clear why that would happen? (E.g. what is the actual fitness advantage being selected for there?)

    I mean, it seems like that’s not impossible, but I don’t know that I’ve ever seen someone argue that there is a selective signal in the genome for it or anything.

  9. Re; Covid, going to be watching the EU total figure for deaths per million over the next few days; if the case curve is accurate, then going on lag that’s shown up, death rate should be peaking around now.

    If death rate does not peak around now but looks to continue on upward trahectory, then that will point to measured case declines being more due to exhausted testing capacity and Europe has not really bent curve.

    There are some different curve shapes nationally across Europe, which seems to be depending on where outbreaks are happening subnationally; there’s more of a sudden peak collapse it seems in nations where outbreaks cluster locally, as happened in Spring. UK for’ex has some appearance of plateau due to falling cases nationally while continued rising in Midlands, though this seems to have turned around a bit and now falling in total I think.

  10. Matt, I don’t remember the details but it had something to do with fat accumulation selection in the last 4,000 or so years probably because of famines and whatnot. The implication is that it would be worst for groups with the lowest lean body mass. There is probably a point where higher steppe ancestry not only leads to more fat accumulation but also higher lean body mass but idk what that point is.

  14. Relating to that: https://www.sciencedaily.com/releases/2020/09/200908101601.htm

    There were groups like Gravettians which stayed in or near the zones covered by ice sheets. Connecting it to what you posted Matt, these Gravettians would have the highest incidences of such figurenes. And I think they do, though I am not sure about a numeric comparison to the more southern Magdalenians and Balkan (WHG?) populations.

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