Scientists find genetic signature of Down syndrome in ancient bones
nytimes.com
nytimes.com
As far as I understand it, we now have the technological capacity to do so, and simply lack the moral and legal capability.
For me this would push occams razor toward the notion that endeavoring to build monumental generational-construction-project tombs was not an act of cultural vanity but actually an informed and practical decision made with some form of ancient knowledge.
Would it be possible that only one of the three chromosomes is passed on from each parent, leading to a normal and healthy child?
The primary cause of Down syndrome is trisomy of chromosome 21, which is what you described. That form is not inherited. A much less common cause, mosaicism, is a random occurrence during cell division and isn't inherited either.
The only form that can be inherited (that we know of) is caused by translocation. Basically a piece of one chromosome can become switched with a piece of another chromosome. If no information is lost, that's a balanced translocation. Those usually still produce a normal phenotype. When the balanced translocation is passed down a generation, it can lose information or pick up extra information and become unbalanced. If the extra information is from chromosome 21, that can become Down syndrome. That's a simplistic explanation, but should do the job.
A similar phenomenon is common in plants. While humans have two copies of DNA, one from each parent, many plants contribute more than one copy of DNA to their offspring, resulting in plants with many more than just two copies of DNA. The number of copies a plant has can vary within the same species. Notably, domesticated plants often have more copies of their DNA than their wild counterparts have, yet they are still reproductively compatible.
In animals like us, multiple copies of DNA, or even just of individual chromosomes, are much more risky, which is why it's so rare (those embryos are typically nonviable).
However, different animal species do often have different numbers of chromosomes, which does provide a pathway to evolutionary divergence and speciation. Typically, species with different numbers cannot reproduce (e.g., humans and chimps), and when they can, the result is often sterile (e.g., horses and donkeys).
There are several ways that species can gain or lose new chromosomes as they evolve, and you are right: duplication of an existing chromosome is one of them, although pretty rare because it often leads to serious health problems or sterility. (More common is the splitting of a chromosome or the fusing of two chromosomes, since these preserve all the genes without duplication. Another possibility is the total deletion of a chromosome, but this is extremely rare because it typically kills the embryo.)
So yes, theoretically, fertile men with trisomy 21 Down's syndrome (they are usually sterile, but there have been exceptions) and women with trisomy 21 Down's syndrome could get together and start a new hominid branch. Over time, the twin chromosomes would undergo selection and diverge from one another, likely in a way that would improve on the general health and fertility issues that people with this syndrome commonly struggle with.
The chances of this happening are very low, but it is certainly not unprecedented in the history of evolution.
Of course this niche doesn’t exist everywhere, for example in Iceland they have a very aggressive abortion campaign against the syndrome.
Besides there is already a social taboo against engaging in sexual intercourse with them because of the substantial power asymmetry. So really the only impediment to speciation is the lack of fertility.
Iceland has extensive support for disabled people though, irrespective of abortion policies. These are of course not mutually exclusive things.
The bad news is that the prognosis is even worse than for the trisomy.
Down syndrome is an example of that anomaly rather than some mutation that’s passed down. It’s an extra partial or complete copy of chromosome 21, and therefore can happen to any couple.
Turner syndrome is another example without the mental issues: https://en.wikipedia.org/wiki/Turner_syndrome
In the larger context, there may be some long term advantages to chromosomal anomalies because their number varies so much between closely related species.
Think r/K evolutionary strategies [https://en.m.wikipedia.org/wiki/R/K_selection_theory]
A species that can produce 1000+ offspring (or more) per mating (with multiple matings per adult lifespan) - like most insects, seaturtles/squids, etc. has little incentive to have high precision/accuracy reproduction.
One that does a small handful (whales, elephants, etc), has a lot of incentive to do so (or self abort early on if there is an issue).
This gets complicated though, because while a single individual in a species which is predominantly r strategy (few offspring), can be ‘more’ on the K side, and vice versa.
And a species which has too much consistency, both genetically and ‘approach’ is very susceptible to inbreeding/mono-cropping issues where a single event/disease can wipe them out, or they can even destroy themselves due to recessive traits.
So there is a general (but diffuse!) evolutionary pressure towards a degree of mutation/error in reproduction in even the most hardcore ‘r’ species (which will necessarily produce a lot of noise/‘wasted paths’) at the species level, alongside a hard evolutionary pressure to reduce it for individuals.
In for example humans. Or elephants. Or whales.
This is also why things like rich/poor, healthy/sick, pretty/ugly, strong/weak, etc. will never go away - they’re outcome distributions along a probability curve due to fundamental different approaches by individual humans due to the necessity of how humans have to be in order for humanity (the species) to survive.
Individuals have strong incentives to ‘tip the scales’ in various ways of course, and societies (at a minimum!) have strong incentives to stop them. It’s why aborting based on gender is illegal in India, for instance. [https://pubmed.ncbi.nlm.nih.gov/7920120/]
Because if everyone had the same attributes in order for everyone to be ‘pretty’ or ‘strong’ or ‘rich’ or whatever, then some hypothetical weight-lifting-infectious-disease (or a famine, or an attack by jealous anti-weightlifters) would wipe out the whole population. And if everyone optimized for ‘rich’ genes (whatever that means), then society would implode, because that literally couldn’t work.
And those types of situations, albeit less light hearted, have, do, and will continue to happen eventually.
In a mosaic version, only a part of your cells are trisomic, perhaps even just as little as 1/5th. In that case, the characteristic symptoms are often fewer and lighter, which would help that person survive in the Stone Age world.
Somewhat belied by the fact that all of the positives were among children under the age of 1. They didn’t make it very far.
The average life expectancy of someone with Trisomy 21 was only 10 as recently as 1960.
So I think you’re wrong in assuming mistreatment or neglect just because the children died young.
I don't believe that for a second, but what I do believe is that 'the masses' have never been so re-broadcast, nor had such a large loud-speaker.
I have mixed feelings. Being exposed to actual violence doesn't seem to make people better, IME. But being so detached from it doesn't seem healthy either.
edit: if you’ve spent any time in them in the last few years you’d see the clear degradation. people can barely speak coherently.
Keep in mind that the number of children on the internet is higher than it has ever been, and children typically also have more free time to comment than adults have.
And with that bit of self-realization, I think it's time to sign off for a bit.
But on the other hand, you wouldn't have been able to broadcast the holes in your knowledge as far, either. And everyone has them - the holes in their knowledge. One of yours seems to be reading communication. If most folks can barely speak coherently - to you - I'd wager that you just aren't putting in the work to better understand colloquial speech.
Test score increases have been continuous and approximately linear from the earliest years of testing to the present. For example, a study published in the year 2009 found that British children's average scores on the Raven's Progressive Matrices test rose by 14 IQ points from 1942 to 2008.
I think this is a red herring. It used to be harder to access the internet, and it selected for a certain type of person. Today, in the era of the smart phone, virtually everyone in wealthy nations is on the internet. Most notably, that includes vast numbers of children.
I bet if you looked poorer countries where few people have internet-connected devices, the quality of discourse is much higher. In particular, there are likely few children participating (and the ones who do likely have unusually proactive and involved parents).
Madness is something rare in individuals — but in groups, parties, peoples, and ages, it is the rule.
The comments on NYT for this article are good. I had a hunch people who had experience caring for such children would show up in the comments, and probably be moving.
Note the heavy sampling bias here. Someone who is struggling to cope and secretly hates their "burden" probably won't want to comment.
> The discovery may help shed light on how prehistoric societies treated children with rare conditions.
I apologize if I mis-summarized that, but this is what I was trying to convey.. Some commenters there said similar things to what I did. The sub heading feels like bait and switch.
I guess "may" is doing a lot here... Like you said, a future hope based on a new ability to identify.
> Als Pastor Niemöller ins Konzentrationslager kam, schrieben wir 1937, als das Konzentrationslager aufgemacht wurde, da schrieben wir 1933, und die damals in die Konzentrationslager kamen, waren Kommunisten. Wer hat sich darum gekümmert? Wir haben es gewußt, es stand in den Zeitungen. Wer hat die Stimme erhoben, etwa die Bekennende Kirche? Wir haben gedacht: Kommunisten, diese Religionsgegner, diese Christenfeinde - "soll ich meines Bruders Hüter sein?" Dann hat man die Kranken, die sogenannten Unheilbaren beseitigt. - Ich erinnere mich eines Gespräches mit einem Menschen, der Anspruch darauf erhob, ein Christ zu sein. Er meinte: Vielleicht ist es ganz richtig, diese unheibaren Menschen kosten den Staat nur Geld, sie sind sich und den andern nur zur Last. Ist es nicht das Beste für alle Teile, wenn man sie aus der Mitte schafft? -- Dann erst ist es an die Kirche als solche herangekommen. Dann haben wir einen Ton geredet, bis er dann in der Öffentlichkeit wieder verstummt ist. Können wir sagen, wir sind nicht schuld? Die Judenverfolgung, die Art und Weise, wie wir die besetzten Länder behandelten, oder die Dinge in Griechenland, in Polen, in der Tschechoslowakei oder in Holland, die doch in der Zeitung gestanden haben. …
Let's… not get into this? It's not the Oppression Olympics, and this has nothing to do with the article.
1) environmental such as cold or swamp preserved them
2) burial preservation which would indicate they were children of those with wealth and status
Obviously these remains if they were buried with jewelry were likely the ancient equivalent of nobility.
https://adscresources.advocatehealth.com/social-sensitivity/....
People with Down's are have individual personalities, just like anyone else.
My daughter has Down's, so we're familiar with several other people with Down's (through support groups, sport groups etc). I can assure you, they are all very different, and this idea that everyone with Down's is happy and smiley all the time needs to die.
However, i speak from experaince having lived with many down syndrome kids for many years. Though they were all manifestly and clearly individuals, there was also a commonality between them. Check out the academic studies in the link I shared which supports this impression.
THe link between selfhood (if I may term it such) and the body is something that has been discussed for centuries, with most of that discussion being mumbo jumbo (eg the four temprements). But there does seem to be some mechanism at work. I know that Crohn's disease and Celiac disease are both associated with certain personalitytypes. That's not to say that there condition defines who they are, rather it informs it.
Off topic, but I hadn't heard much of this. Do you have sources?
I googled. Here's one interesting thing I found: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4814534/
I found claims of correlation with stress and anxiety (seems kind of obvious), and type D personalities (a categorization I've never heard of before, but seemingly includes negativity, hostility, suppressed anger).
It seems hard to me to ascertain whether these are a cause of illness, a reaction to illness, maybe even a vicious-cycle type of reaction that serves to make the illness worse ... Or just correlation. One factor among many. A rut that people fall in. Maybe all of this.
I have no other sources apart from anecdotes from a childhood friend with Celiac. He claimed that it was common knowledge in the Celiac community. I did the same search that you likely did and there seems to be some supporting evidence for such association.
> Or just correlation. One factor among many. A rut that people fall in. Maybe all of this.
I think this likely accounts for much condition-associated personality behavior, but not all.
A few years ago I was diagnosed with Ehlers Danlos. Shortly after I stumbled across this: https://www.ehlers-danlos.com/2017-eds-classification-non-ex...
Of course, the pain of Ehlers will inevitable impact upon personality, that is obvious (fortunately my pain is manageable). But also mentioned is this:
> The underlying mechanisms include genetic risks, problems with the automatic control of body functions, sensitivity to external and internal stimuli, and decreased sense of position. Recent studies have also shown an increase response in emotion processing brain areas which could explain the high emotional reactivity.
'Decreased sense of position' seems so odd and specific and something I clearly recognize in myself.
I know plenty of people who don't identify with their body at all.
The ancient temperamental model assumed that the human body is a mix of Choleric (fire), Sanguine (blood), Phlegmatic (phlegm), and Melancholy. These categories were also assumed to be temperamental architypes whereby (for example) an excess of blood leads to an angry (Choleric) personality.
Of course this is bollocks, but nonetheless demonstrates my point. The idea that 'who we are' is something that is defined only by our brain is wrong. Brain/body traffic seems to be two-way: physical trauma to the body can impact the brain, the nervous system of the digestive tract can impact our moods, lack of vitamin D can negatively impact our emotional outlook, male infant circumcision can alter adult socio-affective processing etc etc.