7 ms·

DNA tests are uncovering the true prevalence of incest (2024)

137 points by georgecmu 1y ago

DoctorOetker 1y ago
A miserably small quantum of solace to people who: 1) grew up and had children 2) don't know much about genetics and the statistics behind it 3) discovered they themselves were born out of incest after they had children 4) blindly assume they will pass on the 25% of duplicate (paternal and maternal strand) recessive genes, i.e. assume their kids also have the 25% of duplicate recessive genes (the percentage mentioned in the article) That genetic percentage falls off very quickly each generation if these next generations mate with genetically healthy people. So the disease burden decreases very quickly, but is still present for some generations, and doesn't fully disappear, as the rest of us all have some of that happening if you'd trace back the 4 grandparents, the 8 greatgrandparents, the 16 great-great-grandparents, etc. Also, most victims or people with traumas in general, feel the logical need to understand: how can one (or we as a society) possibly learn from problems if our understanding of these problems is proactively hindered? To spare you a lot of genetics going in depth into the biological machinery behind genetics, there is a very simplistic way to understand it. Disregarding immune cells, essentially all cells in your body have the same genome, so we speak of an individuals genome when we consider multicellular organism, like humans. As you are undoubtedly aware human organisms have their hereditary traits stored in DNA molecules, called chromosomes. Ignoring the sex chromosome one usually has one chromosome from ones father and another from ones mother. There is an ingenious strategy nature uses here: Imagine whenever a child is created, that somehow half the assets of the father and half the assets of the mother are copied and given to the child. I invite you to literally think of them as devices: thermostats, microwaves, central heating systems. (this is the rough analogy for the homeostasis functions encoded in our genome). Assuming the parents are unrelated, this means you get 2 typically unrelated types or models of refrigerator (one from your father and one from your mother), and the 2 microwaves, one from mother another from father, and 2 thermostats, etc... all your cells have this machinery in them. Now consider the 2 different heating systems you inherited work correctly, but for some reason you inherited the defective thermostat from one of your parents, but a working on from the other. When the cold setpoint is reached both functioning heaters turn on thanks to the working thermostat. And like this it goes with a bunch of different toolsets (the "genes"). Everybody has a few defective devices, but there's a backup of the other parent so we don't notice (or not much at least: suppose both thermostats worked, but one of the heaters was defective: it would still turn on at the same temperature and shut off at the same temperature, but it would take a little longer to reach it, having some influence on your procreation chances in life, but not mortal). Now consider what happens if your father is also your mothers father: consider the grandparents: Via the father: PGF: paternal grandfather < makes up half the genome of the father PGM: paternal grandmother < makes up the other half genome of the father Via the mother: MGF: maternal grandfather < the genome of the father, so half PGF, half PGM MGM: maternal grandmother So a defective device from the paternal grandfather or paternal grandmother has the opportunity to be passed on to you directly through the father, BUT also has the opportunity to be passed on to you via the mother! This drastically increases the odds for defective devices to be backed up by ... the same defective type of device! That is fundamentally what happens... Now another quantum of solace. Apart from genetics, theres also the concept of memetics. The spread and recombination of ideas. Now this doesn't just come half from the father and half from the mother, as we are exposed to other sources of information as well: educational systems, newspapers, friends, other family, etc. But undeniably parents have a strong sway over the opinions, ideas, etc to which a child is exposed in its most formative years. It is healthy to have parents who respectfully hold their own differing opinions, so that children learn to make up their own mind. But it is also a fact that differences of opinion may prevent couples from forming... You are not alone when it comes to being borne of genetic incest, as the article explains, but also, in a weaker but much wider sense, nearly all of us are the result of this intellectual incest, where people grow up hearing identical but flawed viewpoints from both parents for a prolonged period of your life, in its formative years. Nobody is alone.
- jf 1y ago
  I found found this post to be very interesting and am grateful that you wrote it.
toomuchtodo 1y ago
https://archive.today/Sgjb7 https://archive.today/Sgjb7
- zahlman 1y ago
  The article doesn't appear to be paywalled and I'm reading it just fine without JavaScript enabled. Is an archive really necessary?
  - deleted 1y ago
    [deleted]
  - voidnap 1y ago
    [flagged]
    - dang 1y ago
      Please edit out swipes from your comments. This is in the site guidelines: https://news.ycombinator.com/newsguidelines.html https://news.ycombinator.com/newsguidelines.html.
  - tetromino_ 1y ago
    Paywalled here - can only read 2 paragraphs. Possibly paywall is triggered conditionally, for example if you read multiple articles in some time period?
    - Jtsummers 1y ago
      It used to be 5 free a month when they first introduced it years ago. Not sure the current mechanism and policy.
  - john01dav 1y ago
    Many paywalls rely on client side JavaScript to work. My guess is that this has something to do with search engine indexing.
arresin 1y ago
Wow that was very touching.
- bloomingeek 1y ago
  It really was.
searine 1y ago
This is a tragic story, but I think the bigger issue is some places have high levels of cultural acceptance of consanguine relationships.
- 0xcafefood 1y ago
  It's extremely common in South Asian communities (https://www.reddit.com/r/interestingasfuck/comments/10yx3va/rate_of_cousin_marriages_in_south_asiapakistan/ https://www.reddit.com/r/interestingasfuck/comments/10yx3va/...). The UK has a large South Asian diaspora.
  - thelastgallon 1y ago
    Pakistan doesn't represent all of South Asia.
    - 0xcafefood 1y ago
      None of India is looking particularly good, but each state in southern India looks to have 20-25% rates of first-cousin marriages. Pretty high.
      - lazide 1y ago
        Southern India it’s even higher
      - jandrese 1y ago
        The crazy thing is India has ample population to avoid this problem. It's not some isolated tribe or small island community. The reasons have to be social/political.
        lazide 1y ago
        It’s the caste system + specific social factors.
  - dismalaf 1y ago
robertlagrant 1y ago
> And this number is just a floor: It reflects only the cases that resulted in pregnancy, that did not end in miscarriage or abortion, and that led to the birth of a child who grew into an adult who volunteered for a research study. This might not be logical. If your DNA's in UK Biobank you might be more likely to have had a genetic disease stemming from incest.
- HPsquared 1y ago
  A bit like the high number of negative paternity tests. Selection bias is huge.
- AndrewDucker 1y ago
  Biobank is a voluntary data collection system, I thought. It's not based on whether someone is sick. (Unless I've misunderstood somewhere)
  - 2dvisio 1y ago
    Yes. UK Biobank is a voluntary programme. (I work in Genomic)
    - hopelite 1y ago
      [flagged]
  - taeric 1y ago
    I think the assertion is that most people basically don't feel they have anything special genetically. As such, most people just aren't entering these databases that are opt-in. Contrast this to people that do have a genetic oddity about them. Just having the traits is often enough to get people to find out more about them.
    - rcxdude 1y ago
      Perhaps, but it is primarily about allowing researchers to find healthy people with particular genes for their research (most commonly: they suspect a gene is involved in a disease, and while they have plenty of people with that disease and gene, they also need to look for people who have that gene and don't have the disease).
nineplay 1y ago
I think we're going to find that a large number of people who were shamed as "town sluts" were actually abuse victims. Every so often I see nasty comments that 'she got pregnant at 15' or 'she had two kids before finishing high school' with follow-ups blaming poor sex ed. I think people are side stepping the implications, especially if the father is otherwise unknown. Even in my day the girl who got pregnant by the volleyball coach shouldered the bulk of the blame.
- squidbeak 1y ago
  What a term to use about anyone let alone people you suppose to be abuse victims. This is shameful.
  - nineplay 1y ago
    Too late to edit but I meant to say town "sluts". Ah well, a lesson to re-read carefully before posting
    - tomhow 1y ago
      You should be able to edit it now, or email us (hn@ycombinator.com) with an edit we can put in. Probably best to find a different word/phrase to use. It's upsetting to people even if you didn't mean it that way.
    - dang 1y ago
      I've edited your GP comment to say what I believe you meant, but if I got it wrong, please let us know.
  - dang 1y ago
    It made me wince as well, but I doubt that the intent was malicious.
  - Quarrelsome 1y ago
    are you unaware of the meaning of quote marks? They are quoting labels that society will place on them, primarily as a consequence of puritanical thinking acting as a cover up for abuse. What's shameful is hiding the horrors of our reality. I thought their comment was particularly poignant and reflects the actual horrors of abuse when it is uncovered in retrospect, compared to how it was perceived at the time. We see this countless times in our history, abusers lauded, praised, with status, titles, wealth and popular acclaim. Detractors are ignored, slandered and side-lined, and after the abusers die, it transpires all those hushed whispers were true and the detractors were right all along.
deleted 1y ago
[deleted]
ChrisArchitect 1y ago
(2024) Some discussion then: https://news.ycombinator.com/item?id=39765894 https://news.ycombinator.com/item?id=39765894
fsflover 1y ago
> Moore ended up creating a private and invite-only support group on Facebook Sounds like a thing you would never want to share with Facebook given its approach to privacy.
- JimmyBuckets 1y ago
  I don't think the invite-only nature of the group is due to privacy but rather moderation. It seems the point of this group is to assuage shame
  - usefulcat 1y ago
    > Moore ended up creating a private and invite-only support group on Facebook I read GP's comment as being more about the 'on Facebook' part, not so much about 'invite-only'.
- sneak 1y ago
  Entire countries have ceded their b2b and b2c communications channels to WhatsApp. End users don't give any thoughts to privacy, generally speaking. Either they've "nothing to hide", or they have given up due to an overwhelming sense of helplessness and loss of agency on the matter. It's not even a decision anymore. They just type their phone number (aka permanent tracking unique identifier) into the new app and smash "agree".
  - jpc0 1y ago
    My customers are on Whatsapp, my suppliers are on WhatsApp. I can fight WhatsApp all I like but that won’t change, but they will change where they spend their money and whether I can give them my money.
    - fsflover 1y ago
      At least when you create a completely new group, you could try to change things.
dbg31415 1y ago
[flagged]
- dang 1y ago
  Please don't start religious flamewars on HN. It's tedious and evokes worse from others. https://news.ycombinator.com/newsguidelines.html https://news.ycombinator.com/newsguidelines.html
Mistletoe 1y ago
I don't want to read the article that will just upset me, can someone give a percentage?
- qualeed 1y ago
  >One in 7,000 people, according to his unpublished analysis
  - wincy 1y ago
    That’s pretty low, I’d say that’s a cultural success.
    - deleted 1y ago
      [deleted]
    - jvanderbot 1y ago
      Yeah I expected 10x the rate, but sadly those are the "successful" pregnancies.
      - mc32 1y ago
        Also it only would be able to capture cases where reproduction is actually possible --in some cases it obviously is not possible. Another data source would be STD transmission.
    - Quarrelsome 1y ago
      the article gives reasons why its still probably an underestimate.
    - jasonfarnon 1y ago
      the article has a quote “That’s way, way more than I think many people would ever imagine,” but I don't have much intuition with 1/7000. The LLM tells me 1/7000 is the 6'7.5" quantile for US adult males. That doesn't sound too far off from what I would have expected of this type of incest, if I had to hazard a height quantile before reading this article. Maybe I would've gone for 6'9". If it was like 6'4", I would be seriously nauseated. I've never had a friend over 6'5" but a number < that. Which would suggest.
deleted 1y ago
[deleted]
gaoryrt 1y ago
If your parents aren't related, nor their parents, the 30th-generation(roughly 600–900 years depending on generation length) ancestor group size is 2^30, which is about 1.07 billion.
- hinkley 1y ago
  Turns out that due to the way genes splice you have ancestors that you have 0 genes from. The mitochondria and Y chromosome are conserved, but even 9 generations back there are good odds that some of your ancestors have been completely spliced out of your DNA, and a few whom you only got a couple genes from. https://www.youtube.com/watch?v=HclD2E_3rhI https://www.youtube.com/watch?v=HclD2E_3rhI "only 72% of these 7th great grandparents will give you some of your genetics" "over less than 400 years, 97% of your ancestors contribute nothing to your genetics"

137 points by georgecmu 1y ago

A miserably small quantum of solace to people who: 1) grew up and had children 2) don't know much about genetics and the statistics behind it 3) discovered they themselves were born out of incest after they had children 4) blindly assume they will pass on the 25% of duplicate (paternal and maternal strand) recessive genes, i.e. assume their kids also have the 25% of duplicate recessive genes (the percentage mentioned in the article) That genetic percentage falls off very quickly each generation if these next generations mate with genetically healthy people. So the disease burden decreases very quickly, but is still present for some generations, and doesn't fully disappear, as the rest of us all have some of that happening if you'd trace back the 4 grandparents, the 8 greatgrandparents, the 16 great-great-grandparents, etc. Also, most victims or people with traumas in general, feel the logical need to understand: how can one (or we as a society) possibly learn from problems if our understanding of these problems is proactively hindered? To spare you a lot of genetics going in depth into the biological machinery behind genetics, there is a very simplistic way to understand it. Disregarding immune cells, essentially all cells in your body have the same genome, so we speak of an individuals genome when we consider multicellular organism, like humans. As you are undoubtedly aware human organisms have their hereditary traits stored in DNA molecules, called chromosomes. Ignoring the sex chromosome one usually has one chromosome from ones father and another from ones mother. There is an ingenious strategy nature uses here: Imagine whenever a child is created, that somehow half the assets of the father and half the assets of the mother are copied and given to the child. I invite you to literally think of them as devices: thermostats, microwaves, central heating systems. (this is the rough analogy for the homeostasis functions encoded in our genome). Assuming the parents are unrelated, this means you get 2 typically unrelated types or models of refrigerator (one from your father and one from your mother), and the 2 microwaves, one from mother another from father, and 2 thermostats, etc... all your cells have this machinery in them. Now consider the 2 different heating systems you inherited work correctly, but for some reason you inherited the defective thermostat from one of your parents, but a working on from the other. When the cold setpoint is reached both functioning heaters turn on thanks to the working thermostat. And like this it goes with a bunch of different toolsets (the "genes"). Everybody has a few defective devices, but there's a backup of the other parent so we don't notice (or not much at least: suppose both thermostats worked, but one of the heaters was defective: it would still turn on at the same temperature and shut off at the same temperature, but it would take a little longer to reach it, having some influence on your procreation chances in life, but not mortal). Now consider what happens if your father is also your mothers father: consider the grandparents: Via the father: PGF: paternal grandfather < makes up half the genome of the father PGM: paternal grandmother < makes up the other half genome of the father Via the mother: MGF: maternal grandfather < the genome of the father, so half PGF, half PGM MGM: maternal grandmother So a defective device from the paternal grandfather or paternal grandmother has the opportunity to be passed on to you directly through the father, BUT also has the opportunity to be passed on to you via the mother! This drastically increases the odds for defective devices to be backed up by ... the same defective type of device! That is fundamentally what happens... Now another quantum of solace. Apart from genetics, theres also the concept of memetics. The spread and recombination of ideas. Now this doesn't just come half from the father and half from the mother, as we are exposed to other sources of information as well: educational systems, newspapers, friends, other family, etc. But undeniably parents have a strong sway over the opinions, ideas, etc to which a child is exposed in its most formative years. It is healthy to have parents who respectfully hold their own differing opinions, so that children learn to make up their own mind. But it is also a fact that differences of opinion may prevent couples from forming... You are not alone when it comes to being borne of genetic incest, as the article explains, but also, in a weaker but much wider sense, nearly all of us are the result of this intellectual incest, where people grow up hearing identical but flawed viewpoints from both parents for a prolonged period of your life, in its formative years. Nobody is alone.

jf 1y ago
I found found this post to be very interesting and am grateful that you wrote it.

toomuchtodo 1y ago

https://archive.today/Sgjb7 https://archive.today/Sgjb7

zahlman 1y ago
The article doesn't appear to be paywalled and I'm reading it just fine without JavaScript enabled. Is an archive really necessary?
- deleted 1y ago
  [deleted]
- voidnap 1y ago
  [flagged]
  - dang 1y ago
    Please edit out swipes from your comments. This is in the site guidelines: https://news.ycombinator.com/newsguidelines.html https://news.ycombinator.com/newsguidelines.html.
- tetromino_ 1y ago
  Paywalled here - can only read 2 paragraphs. Possibly paywall is triggered conditionally, for example if you read multiple articles in some time period?
  - Jtsummers 1y ago
    It used to be 5 free a month when they first introduced it years ago. Not sure the current mechanism and policy.
- john01dav 1y ago
  Many paywalls rely on client side JavaScript to work. My guess is that this has something to do with search engine indexing.

arresin 1y ago

Wow that was very touching.

bloomingeek 1y ago
It really was.

searine 1y ago

This is a tragic story, but I think the bigger issue is some places have high levels of cultural acceptance of consanguine relationships.

0xcafefood 1y ago
It's extremely common in South Asian communities (https://www.reddit.com/r/interestingasfuck/comments/10yx3va/rate_of_cousin_marriages_in_south_asiapakistan/ https://www.reddit.com/r/interestingasfuck/comments/10yx3va/...). The UK has a large South Asian diaspora.
- thelastgallon 1y ago
  Pakistan doesn't represent all of South Asia.
  - 0xcafefood 1y ago
    None of India is looking particularly good, but each state in southern India looks to have 20-25% rates of first-cousin marriages. Pretty high.
    - lazide 1y ago
      Southern India it’s even higher
    - jandrese 1y ago
      The crazy thing is India has ample population to avoid this problem. It's not some isolated tribe or small island community. The reasons have to be social/political.
      - lazide 1y ago
        It’s the caste system + specific social factors.
- dismalaf 1y ago

robertlagrant 1y ago

> And this number is just a floor: It reflects only the cases that resulted in pregnancy, that did not end in miscarriage or abortion, and that led to the birth of a child who grew into an adult who volunteered for a research study. This might not be logical. If your DNA's in UK Biobank you might be more likely to have had a genetic disease stemming from incest.

HPsquared 1y ago
A bit like the high number of negative paternity tests. Selection bias is huge.
AndrewDucker 1y ago
Biobank is a voluntary data collection system, I thought. It's not based on whether someone is sick. (Unless I've misunderstood somewhere)
- 2dvisio 1y ago
  Yes. UK Biobank is a voluntary programme. (I work in Genomic)
  - hopelite 1y ago
    [flagged]
- taeric 1y ago
  I think the assertion is that most people basically don't feel they have anything special genetically. As such, most people just aren't entering these databases that are opt-in. Contrast this to people that do have a genetic oddity about them. Just having the traits is often enough to get people to find out more about them.
  - rcxdude 1y ago
    Perhaps, but it is primarily about allowing researchers to find healthy people with particular genes for their research (most commonly: they suspect a gene is involved in a disease, and while they have plenty of people with that disease and gene, they also need to look for people who have that gene and don't have the disease).

nineplay 1y ago

I think we're going to find that a large number of people who were shamed as "town sluts" were actually abuse victims. Every so often I see nasty comments that 'she got pregnant at 15' or 'she had two kids before finishing high school' with follow-ups blaming poor sex ed. I think people are side stepping the implications, especially if the father is otherwise unknown. Even in my day the girl who got pregnant by the volleyball coach shouldered the bulk of the blame.

squidbeak 1y ago
What a term to use about anyone let alone people you suppose to be abuse victims. This is shameful.
- nineplay 1y ago
  Too late to edit but I meant to say town "sluts". Ah well, a lesson to re-read carefully before posting
  - tomhow 1y ago
    You should be able to edit it now, or email us (hn@ycombinator.com) with an edit we can put in. Probably best to find a different word/phrase to use. It's upsetting to people even if you didn't mean it that way.
  - dang 1y ago
    I've edited your GP comment to say what I believe you meant, but if I got it wrong, please let us know.
- dang 1y ago
  It made me wince as well, but I doubt that the intent was malicious.
- Quarrelsome 1y ago
  are you unaware of the meaning of quote marks? They are quoting labels that society will place on them, primarily as a consequence of puritanical thinking acting as a cover up for abuse. What's shameful is hiding the horrors of our reality. I thought their comment was particularly poignant and reflects the actual horrors of abuse when it is uncovered in retrospect, compared to how it was perceived at the time. We see this countless times in our history, abusers lauded, praised, with status, titles, wealth and popular acclaim. Detractors are ignored, slandered and side-lined, and after the abusers die, it transpires all those hushed whispers were true and the detractors were right all along.

deleted 1y ago

[deleted]

ChrisArchitect 1y ago

(2024) Some discussion then: https://news.ycombinator.com/item?id=39765894 https://news.ycombinator.com/item?id=39765894

fsflover 1y ago

> Moore ended up creating a private and invite-only support group on Facebook Sounds like a thing you would never want to share with Facebook given its approach to privacy.

JimmyBuckets 1y ago
I don't think the invite-only nature of the group is due to privacy but rather moderation. It seems the point of this group is to assuage shame
- usefulcat 1y ago
  > Moore ended up creating a private and invite-only support group on Facebook I read GP's comment as being more about the 'on Facebook' part, not so much about 'invite-only'.
sneak 1y ago
Entire countries have ceded their b2b and b2c communications channels to WhatsApp. End users don't give any thoughts to privacy, generally speaking. Either they've "nothing to hide", or they have given up due to an overwhelming sense of helplessness and loss of agency on the matter. It's not even a decision anymore. They just type their phone number (aka permanent tracking unique identifier) into the new app and smash "agree".
- jpc0 1y ago
  My customers are on Whatsapp, my suppliers are on WhatsApp. I can fight WhatsApp all I like but that won’t change, but they will change where they spend their money and whether I can give them my money.
  - fsflover 1y ago
    At least when you create a completely new group, you could try to change things.

dbg31415 1y ago

[flagged]

dang 1y ago
Please don't start religious flamewars on HN. It's tedious and evokes worse from others. https://news.ycombinator.com/newsguidelines.html https://news.ycombinator.com/newsguidelines.html

Mistletoe 1y ago

I don't want to read the article that will just upset me, can someone give a percentage?

qualeed 1y ago
>One in 7,000 people, according to his unpublished analysis
- wincy 1y ago
  That’s pretty low, I’d say that’s a cultural success.
  - deleted 1y ago
    [deleted]
  - jvanderbot 1y ago
    Yeah I expected 10x the rate, but sadly those are the "successful" pregnancies.
    - mc32 1y ago
      Also it only would be able to capture cases where reproduction is actually possible --in some cases it obviously is not possible. Another data source would be STD transmission.
  - Quarrelsome 1y ago
    the article gives reasons why its still probably an underestimate.
  - jasonfarnon 1y ago
    the article has a quote “That’s way, way more than I think many people would ever imagine,” but I don't have much intuition with 1/7000. The LLM tells me 1/7000 is the 6'7.5" quantile for US adult males. That doesn't sound too far off from what I would have expected of this type of incest, if I had to hazard a height quantile before reading this article. Maybe I would've gone for 6'9". If it was like 6'4", I would be seriously nauseated. I've never had a friend over 6'5" but a number < that. Which would suggest.

deleted 1y ago

[deleted]

gaoryrt 1y ago

If your parents aren't related, nor their parents, the 30th-generation(roughly 600–900 years depending on generation length) ancestor group size is 2^30, which is about 1.07 billion.

hinkley 1y ago
Turns out that due to the way genes splice you have ancestors that you have 0 genes from. The mitochondria and Y chromosome are conserved, but even 9 generations back there are good odds that some of your ancestors have been completely spliced out of your DNA, and a few whom you only got a couple genes from. https://www.youtube.com/watch?v=HclD2E_3rhI https://www.youtube.com/watch?v=HclD2E_3rhI "only 72% of these 7th great grandparents will give you some of your genetics" "over less than 400 years, 97% of your ancestors contribute nothing to your genetics"