The headline is a little surprising since DNA only survives intact for relatively short time but the fragment analysis made it possibleto go back 5000 years was kind of wild to non expert here. Also my immediate reaction was how could this be good genetic thing to pass on but all the matches were children either under one year or died prior to birth.
Relatively recent advances allow for going back way more than 5000 years. Just last week Nova on PBS did an episode profiling one of the main contributors to pushing the limit back. https://www.pbs.org/video/hunt-for-the-oldest-dna-zckys0/
It seems to me that this would validate the practice of sarcophagizing Egyptian pharaohs such that they can be reborn in the afterlife.
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.
Even if we could clone them, is it really a form of rebirth? They'd have no memory of their previous life - it's as much a form of rebirth as me freezing my sperm to be used after my death.
Infertility rates are extremely high for individuals with Down’s syndrome, so it’s very uncommon to pass on Downs Syndrome from an adult with Down’s to a child
Given that Down Syndrome is caused by an extra chromosome, I'm kinda curious how that would be inherited. Like if you have two people with Down's would there be a possibility of offspring with an extra chromosome pair? Could that in the long term lead to speciation?
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.
Right that makes sense. I guess what happens in all of these scenarios is having an extra copy of one particular gene, causes it to become overexpressed, which in turn leads to all these issues?
It's actually many, many genes that are overexpressed and result in the Down syndrome phenotype. My work is with adults with DS and Alzheimer disease--in this case, triplication of the amyloid precursor protein (APP) gene on chromosome 21 nearly guarantees accelerated development of cerebral amyloid deposition compared to typically developing people. But that's just a miniscule part of the Down syndrome phenotype.
It's actually many, many genes that are overexpressed and result in the Down syndrome phenotype. My work is with adults with DS and Alzheimer disease--in this case, triplication of the amyloid precursor protein (APP) gene on chromosome 21 nearly guarantees accelerated development of cerebral amyloid deposition compared to typically developing people. But that's just a miniscule part of the Down syndrome phenotype.
>Like if you have two people with Down's would there be a possibility of offspring with an extra chromosome pair? Could that in the long term lead to speciation?
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.
They certainly have a good ecological niche to get started in. When I see people with Down syndrome out and about I only get more inclined to support policies that allocate resources to them.
Of course this niche doesn’t exist everywhere, for example in Iceland they have a very aggressive abortion campaign against the syndrome.
I suspect that we would only see a speciation event like this if people with Down's syndrome were segregated from people without Down's syndrome and allowed/forced to form a parallel society. It's hard to imagine modern human society tolerating such an apartheid, leper-colony style of treatment of people with Down's syndrome, however.
Segregation would take them out of the ecological niche where normal people provide for them. They’d be back to Stone Age survival outcomes.
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.
It doesn’t really help if you’re trying to branch out the hominid tree into a future Homo mongolensis, but don’t even get to see the light of day to enjoy any of those accommodations.
With teeth, you can go really far, because in cool, dry conditions they can be preserved for tens of thousands, if not hundreds of thousands, of years. Also, you only need a tiny amount of genetic material to analyse. Of course, having some genetic material is very different from having complete DNA. I guess in this case the researchers just got lucky and got the right segment after all.
Human DNA can be preserved for a very long time if it's in cold, dry conditions and little oxygen. And the DNA tends to be pretty damaged/fragmented anyway. Samples up to 300Kya have been sequenced from caves in Spain.
Apparently there have been a ton of advances in reading ancient DNA that make a lot more than 5000 years possible. There is a fairly readable summary of it all in the form of a somewhat-dry book, "Who We Are and How We Got Here", by David Reich.
The Reich book is phenomenal. For something a little more accessible, there is the Nova episode: "Hunt for the Oldest DNA." It's a bit breathless if one has already encountered Reich, but gets the gist across.
Perhaps the existence of atypical "weaker" children promotes compassion in the culture ultimately leading to better outcomes for the culture as a whole.
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.
My point is that perhaps there is a reason that this chromosome causes this issue when an additional copy is present. If other chromosomes do not cause the same issues, why not? Why would that same reason not hold for chromosome 21?
You have it backwards here, Down syndrome is unusual for being viable not because the symptoms are so terrible. Most chromosomal anomalies result in a non viable egg / sperm which doesn’t result in a live birth. The majority don’t even last long enough for someone to notice they were potentially pregnant.
In the larger context, there may be some long term advantages to chromosomal anomalies because their number varies so much between closely related species.
In other words, Down syndrome isn't inherited therefore not something evolutionary forces can act on. The only way around that is if the base rate of chromosomal anomaly is heritable, yes?
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.
It is a pity that there is no discussion if the detected amounts of extra 21 chromosome indicated a full Down syndrome or a mosaic version thereof.
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.
It also seems likely that mosaic trisomy 21 is quite common but often asymptomatic. And the milder it is the lower the odds that it will be picked up even by genetic testing.
In addition, I believe that infant mortality in ancient Rome was perhaps 30% (so 1/3 died before one). I don't know if that can be generalised but it was tough for everyone to begin with.
Mortality of young children was historically so high that some cultures didn't even give them names until they were 5 or so, to avoid emotional attachment.
I don't generally agree with the masses being dumber than ever, but I do think people have a pretty warped view of nature these days. We heavily censor real violence; its partially why people (in US at least) have such a high tolerance for "violent" shows -- they are so far detached from real violence it doesn't even register as something actually bad.
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.
This is a side effect of the internet becoming more accessible to everyone.
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 realize that if you were born just a few centuries earlier, you would have probably been illiterate - and if you were literate, you probably couldn't read anything beyond religious texts.
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.
The cultural context of colloquial speech is incredibly difficult to pick up online. It is literally never communicated, you have to scrape Culture Shock and reaction videos for weeks to piece it together. Or study full time, or live there.
I'm not certain that "dumber than they’ve ever been" is true. The "Flynn Effect" seems well substantiated:
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.
Ok cool now do this same measurement of test scores since 2020. It’s also well known that this hypothesis has not been holding up well in the last 30 years.
So was 2020 the peak of intelligent commentary on the internet? I seem to recall that the quality of discourse was much higher around the year 2000, even though average IQ was higher in 2020.
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).
The red herring is a fair point. I have had to moderate comment sections off and on over the years and there are times when the magnitude of stupidity overwhelms you, so I was venting a bit.
Improvements in environmental factors, that probably had driven the Flynn effect, have topped out. And now the effect seems to be reversed (at least in developed countries).
The article says it sheds light on how people with Downs were treated but doesn't really explain that.
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.
The only thing I picked up was that in an area and time where the dead were usually cremated, they left the corpses of the ones with Downs intact with accompanying jewelry as far as we can tell, so there was something special with that treatment - it's just hard to get information about the why and it's a very small number in just one culture/area.
At a guess, it's because they had to take special care of them, and that was significant for obvious reasons. Cousin Grug who just works is less special than the sweet baby who needs attention all the time.
> 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.
It doesn't say that, it says it might shed light i.e. remains with the condition can now be identified which may over time tell us more about how such people were treated.
> 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.
It's obvious the way they were treated was through death. I can't imagine historical societies wouldn't immediately kill someone who was obviously so different than the masses. I mean, weren't those societies the same ones who would burn suspected witches at the stake?
The witch burning garbage happened within the last 500 years. That's way closer to today than the 5000 years ago we're talking about. And this seems very culturally dependent.
Yes all this prejudicial junk is bad, and these attitudes still exist. It doesn't make sense to apply "shit bad, yo" to all of human civilization 5000 years ago and say, based only on those vibes, that there was a particular way that certain people were treated. You have to make too many assumptions.
I hope you are not elevating these two topics to the same level. The way we treat trans person in the West is wildly better. Unimaginably better even (see holocaust).
The Opernplatz book burning was the destruction of the archives of the Institut für Sexualwissenschaft, which was basically the research centre for trans and intersex people. Plenty of people were persecuted in the Holocaust:
> 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.
Human empathy is not a new thing. The behavior you describe would be entirely dependent on culture. You could easily imagine a culture where people with down syndrome were venerated as a gift from the gods. Outside of these extremes it's entirely plausible that members of the tribe who needed to be looked after were simply looked after. Your imagination of all historical societies as entirely savage is incredibly reductive.
Did you read the article? It says they were buried with jewelry, in a location where they usually cremated people. That suggests they were revered in some way.
This indicates they were singled out. Was it reverence or an offering to the gods to prevent repetition (or maybe a combination of both) is anyone's guess.
Anyone who has actually worked or lived with people with Down's Syndrome knows that's an unrealistic stereotype.
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.
I respect your experience with yourvdaughter. I absolutely did not mean to two-dimensionalise anyone with downs and apologize if I gave such impression.
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.
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.
> Off topic, but I hadn't heard much of this. Do you have sources?
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.
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 don't think it is a issue of 'identifying with their body' rather than a situation where the body and the self inform each other.
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.
I've read a lot of wild shit before but I've never come across a claim that Down Syndrome is caused by vaccines. Care to share the source of this information?
He won’t be able to provide a source, at least not a legitimate one. Down syndrome aside, no vaccine “modifies your DNA” despite many claiming the opposite. Whether that claim continues to propagate due to ignorance or malice is a different question.
I’m not even sure why GP brought it up, since the OP article has absolutely nothing to do with pharmaceuticals nor pharma companies.
