The article (which is from 2023 by the way) doesn't discuss the findings of the DNA analysis, so I went and looked up the original - https://doi.org/10.1038/s41586-023-06035-2
> with estimates of present-day human and faunal contamination both below 1%. Comparisons with present-day human populations²⁶ using ƒ3-statistics and D-statistics²⁷,²⁸ show high affinities to Native Americans (Extended Data Fig. 5). When projected into a principal component analysis with other ancient human individuals (Fig. 3c), DCP1 falls within a group of Ancient North Eurasian individuals from further east in Siberia, which includes the approximately 24 ka Mal’ta 1 and the approximately 17 ka Afontova Gora 3 individuals²⁹,³⁰. Both of these individuals are genetically closer to DCP1 than non-Ancient North Eurasian individuals when tested with D-statistics (Extended Data Fig. 6b), and all three show similar affinities to ancient Siberians and Native Americans with ƒ3-statistics and D-statistics
3 billion bases long[...]we were able to recover roughly 70 per cent
It's impressive how resilient DNA is as a data storage medium. That's the equivalent of ~500MB of raw data they've recovered, if my calculations are correct.
They didn't sequence the whole human genome (~3 billion bases) for multiple reasons. I am not an expert on ancient DNA but I will try to explain the paper as best I can:
1. Contamination with other flora and fauna DNA
2. Relative low proportions of human DNA
3. The DNA is usually highly degraded, which limits the analyses to short read sequencing (in this case they used 76 bp reads). The halflife of human DNA is ~521 years.
To mitigate these problems they used multiple targeted approaches including one to isolate mitochondrial DNA, where they managed to sequence the whole ~16kb human mtDNA, where each base was covered by 62 sequencing reads on average (62x coverage).
They used another to isolate specific regions containing single nucleotide polymorphisms (SNPs), which are DNA mismatches known to be related to ancient human DNA and humans. They targeted 470,724 single nucleotide polymorphisms of which 70% (336,429) were recovered.
They did perform shotgun sequencing on all of the DNA isolated, but due to species assignment issues they again focused on fragments that contain diagnostic SNPs in these cases they only recovered a small number of SNPs per sample, again due to the relatively low proportion of human DNA and its degradation (20,526, 3,734, 124,862, 85,901, 34,756, 41,632, 34,677 and 72,992) as per the legend in figure 3.
"matching" is exactly how we do DNA sequencing right now. The current technology is called next generation sequencing (NGS), we multiply the DNA and perform matching digitally to construct the full DNA.
It's quite fascinating. It's like if order to figure out the shape of a teacup, we generate thousands of identical copies, smash them all to rather small bits, and then try to count the different types of shards as a first step to piecing together one full copy. Impressive that it works.
> It's like if order to figure out the shape of a teacup, we generate thousands of identical copies, smash them all to rather small bits, and then try to count the different types of shards as a first step to piecing together one full copy. Impressive that it works.
Yes, but you've got the order wrong.
The teacup is smashed before all of the identical copies are created.
It's not fascinating; it's an endless source of trouble. We only do it because we don't have sequencers that produce extremely long (chromosome length) high quality reads, especially in sequences that contain a lot of repetition. This has been a source of errors and ambiguity for as long as we've used shotgun.
This is a great analogy. One small change is that there are two ways to reassemble it. One is to try to blindly put the pieces together and fork a teacup (read assembly) vs trying to use a picture of the teacup to figure out where the pieces go (read alignment / mapping)
Probably not, not nearly enough material remained to make an accurate clone. The article mentions 70% recovery rate; according to the internet, humans share 98% of DNA with chimpanzees (and 35% with daffodils), so unless you have 100% or 99.9999% of the DNA, the clone will be imperfect at best and a Thing That Should Not Be at worst.
Keep in mind that this is survivorship bias. The vast majority of DNA from this period has lots. Sure, there is tons that exists but we haven't found but without a doubt almost all of it has been lost.
This is DNA that happened to be the right conditions to survive. It isn't so much that the medium is resilient but that if stored in the correct conditions it can survive.
It makes me think about how many ancient ruins don't exist simply because the people nearby didn't see reason not to reuse all that convenient unowned pre-quarried rock.
Even today, it's not a very compelling plea: "No, don't tear down the recently-abandoned building, it would look cool several hundred years after you die."
So too on the microscopic label, if there are convenient molecules nobody else is using...
"Spolia" is a fun architectural term for this sort of material reuse, particularly with the more interesting decorative pieces. Many of those stones taken from ancient buildings have become notable newer ancient buildings in their own right.
> It makes me think about how many ancient ruins don't exist simply because the people nearby didn't see reason not to reuse all that convenient unowned pre-quarried rock.
In the case of Ostia near Rome, they mined it for building material until it became a malaria swamp. It wasn't drained until the 20th century. Around 20% of the workers draining the swap contracted malaria.
I was going to say... except without that mole on your arm. But then I thought, it probably has all kinds of battle scars with disease and other adversity coded in it, making a mole inconsequential.
Thinking on how to save things long term is a fun exercise. If I were super rich and felt that highly of myself, I would totally build a monument to myself built to last the ages; elevated (against flooding), tonnes of erosion resistant rock, a library of all human knowledge in many different formats, sealed off. But with an exact copy near it for tourists.
You'd find yourself in company with many religious organizations. The Mormon Church has a couple of records vault carved into the granite outside SLC, while the church of Scientology has 3 geographically separated primary vaults dug into the mountains (Petrolia and Creston CA, and a place in the desert outside Albuquerque).
It’s even more impressive when you compare it to rna, which “lives” minutes. Take away the pair strand, add a hydroxyl group and a uracil, and it’s a totally different thing.
Honestly, scientific papers. The pain of jargon will be less than the pain of a popsci book. Especially with all the tools to rewrite/summarize/search these days.
A good start would be the review articles listed here: https://scholar.google.com/scholar?q=rna+half-life&hl=en&as_.... If there's a paywall, use sci-hub or check the lab's page for a pdf. I should caveat that there is no one rna half life, some live much longer
Ha! I'm sorry. not trying to be cagey/dismissive. There's no paper that must be read: they're all nodes in a network. All I can do is point you to a cluster, w/ the right filter and jargon search terms. Apologies if I came off out of pocket.
Check out the review articles in the “Nature Reviews” journals, like “Nature Reviews Genetics”. These articles are written by experts but designed for a non-specialist audience (with undergraduate science education).
I think of the error correction codes used by CDs.
But for DNA, the data is needed to literally stay alive as replication occurs constantly through our bodies. And this has been refined over maybe billions of years.
Oh great when i get into old age not only will I forget my password but my DNA will have mutated to the point that it technically isn't my password any longer
You could likely store them in the junk DNA without much risk, as long as you avoid encoding sequences that are the start of coding regions. That said, if you managed to inject them into every cell of your body, this would be the biological equivalent of dropping pamphlets containing your passwords everywhere you go.
If the OP is anything like me, then they have no trust in number theory researchers and deliberately choose passwords like "141592" so they can be sure
I enjoy thinking about this. Not only is a sequence of digits encoding the complete works of Shakespeare in there somewhere, it's in there again. And again, an infinite number of times.
> The cool and dry conditions in the cave have made it possible for scientists to recover preserved DNA left behind by ancient Denisovans, Neanderthals and humans, all of whom occupied the cave at different times over 40,000 years.
That's a long time to have people live in a particular area generally, and a particular "home" in particular.
AIUI, some of the oldest writing we have dates to Ur III at 2000 BC, so that's 'only' 4000 years ago, or perhaps the Uruk period, which at 3500 BC, is 5500 years old:
this is just the begining of DNA as a tool in archiology.
Earlier work with densovian dna, showed not only a genetic profile,of indivuals, it showed a familial relationship, father/daughter.
The implication is that we will start to get a clearer look into human migration patterns ,including tribal, and familial groups, which while interesting, will also be prone to every kind of abuse in the forwarding of various agendas,...racial,ethnic,religios, nationalistic.
Makes me want to stir the pot sometimes, and feed
back in a lurid interpretation of ancient DNA, proving, i dont know, how about our ancestors throwing off our alien overlords, but now the death star has activated and is beaming alien DNA
data right into us from the 5G, but, but, (marketing angle), ....eating , "product xx" or product xy, strengthens your imune system and prevents the alien download from finishing.
The real issue in my blathering, is that fiction
is fighting an uphill battle, to be stranger than reality.
I thought that it was already established that we're descendant of the ancient astronauts from the 12 Colonies of Kobol, and that the "mitochondrial Eve" was a child of a human and a Cylon.
(Part of me wishes to see this resurface as a bona fide religion, oblivious to the source material.)
Denisova cave has been known for about 150 years or so. Back in the 1970s, the Soviet Union sent some archaeologists out to see what was in the cave. They found some upper paleolithic stuff (e.g. like what the article is about), as well as some mousterian stuff (very weird this far north and east). They did excavations over the next couple of decades and eventually, some of the dating/sequencing technology improved to the point where it could actually be used on the cave artifacts. That's when they discovered denisovans and immediately made the cave one of the most important archaeological sites on the planet. There's been no lack of funding since.
It says a lot about the state of discourse and gender science that I can't tell if you genuinely don't understand or if you are being facetious.
But assuming you are being genuine: your sex (faka gender) is encoded in your DNA on the 23rd chromosomal pair. If you have two X chromosomes (XX), you are a female human (woman). If you have one X and one Y (XY), you are male human (man). These chromosomes dictate your sexual development (organs/hormones/etc). There are some people (estimated at 1-2% of the human population) who are "intersex", in that they don't have an XX or XY pair, but some variation thereof (XXY, XYY, etc). However even these variations generally fall under one or the other umbrella of male or female. e.g. Klinefelter syndrome (XXY) is generally going to present as male (albeit frequently with poorly developed testicles and other complications). Genes are complicated so this is a bit of an oversimplification.
To make this more about sex itself (since humans are a sexually reproducing species and that is why we are having this conversation at all), there are effectively three options for all humans: you produce small gametes (sperm / male) or you produce large gametes (eggs / female), or you produce neither due to some complication and therefore cannot participate in procreation. This is dictated almost wholly by your DNA.
So, back to the article: they know the DNA in the deer tooth was from a woman because (presumably) the 23rd chromosome was an XX pair.
Just to add one more wrinkle to the link between DNA and the presentation of sex, there is also androgen insensitivity syndrome, in which the person has a Y chromosome, but the developing body does not react to the testosterone produced by the testes.
The result is someone who may appear to be female, have female genitals, but has testes where ovaries would be expected. It's often not discovered until puberty doesn't happen as expected, and they discover they can't have children.
Like all these conditions, this is on something of a spectrum depending on how total it is.
As you say, genes are complicated. So much more so than is often implied in reporting of discoveries of "a gene for X".
I was a little blithe with my reply here, and feel bad about the scientific inaccuracy I'm perpetuating. The "everyone in between" spectrum often has strong signals, but sometimes it's not very strong straight from DNA alone! And it's also incredibly complex, far far more complex than doing mutation calls, to the point that automating it is quite difficult. Sure, finding XX, XY, XXY, and the many other combinations of sex chromosomes as they appear in nature is easy. Finding subtle inactivations of the genes on the Y chromosome is much harder. In fact analysis of genomes of intersex people is a common use of consumer whole genome and whole exome sequencing, so any consumer sequencing company that simply reports XX as female and XY as male is laughably amateurish, and your customer support lines will be swamped with extremely knowledgeable self-educated intersex people that will being providing tons of information for the company to up their game.
> so any consumer sequencing company that simply reports XX as female and XY as male is laughably amateurish
To my knowledge there is no XX person who can produce sperm and there is no XY person who can produce eggs. So while "XX is female" is over-simplified, "XX is not male" seems fairly clear.
> your customer support lines will be swamped with extremely knowledgeable self-educated
In no other field this combination (self-educated, actually knowledgeable, and calling customer support) seems to exist, so that alone might be worth further study.
They are highly motivated people trying to understand the genetic basis of themselves better, and have usually been seeing doctors throughout their lives towards that end, and usually they'll know more than their doctors because of the rarity of their phenotypes. I have tons of respect for that.
The article says that it belonged to a species of deer called “wapiti”. Since I never heard of it, I looked it up and it’s just an elk. Why didn’t the article just say “elk” which is the much more common term?
- Elk is ambiguous. There's an Elk/Wapiti in North America, Central Asia, and East Asia, and another species of deer referred to as an "Elk" by people in Eurasia, but which is known as a "Moose" in North America.
- Because journalists these days don't have time to look these kinds of things up. The original paper only refers to it as wapiti/cervus canadensis/deer. If the whoever wrote that article knew it refers to an elk, they'd have pointed that out for the reader.
Elk is pretty ambiguous — it refers to different species depending on the context (in Europe, ‘elk’ refers to what in north America is called a moose. Wapiti is a name for what ‘elk’ refers to in North America). You get a similar problem with the words ‘hawk’ and ‘buzzard’
And badger -- In Europe they are small adorable members of the Meles genus. In the Americas, Africa, and Asia the word refers to larger and more aggressive animals in the Taxidea and Mellivora genera that just look superficially like Meles.
The wapiti is the animal on the reverse of the Canadian 25 cent definitive coin. Perhaps the folks who write the article are just educated and worldly.
The article (which is from 2023 by the way) doesn't discuss the findings of the DNA analysis, so I went and looked up the original - https://doi.org/10.1038/s41586-023-06035-2
> with estimates of present-day human and faunal contamination both below 1%. Comparisons with present-day human populations²⁶ using ƒ3-statistics and D-statistics²⁷,²⁸ show high affinities to Native Americans (Extended Data Fig. 5). When projected into a principal component analysis with other ancient human individuals (Fig. 3c), DCP1 falls within a group of Ancient North Eurasian individuals from further east in Siberia, which includes the approximately 24 ka Mal’ta 1 and the approximately 17 ka Afontova Gora 3 individuals²⁹,³⁰. Both of these individuals are genetically closer to DCP1 than non-Ancient North Eurasian individuals when tested with D-statistics (Extended Data Fig. 6b), and all three show similar affinities to ancient Siberians and Native Americans with ƒ3-statistics and D-statistics
3 billion bases long[...]we were able to recover roughly 70 per cent
It's impressive how resilient DNA is as a data storage medium. That's the equivalent of ~500MB of raw data they've recovered, if my calculations are correct.
They didn't sequence the whole human genome (~3 billion bases) for multiple reasons. I am not an expert on ancient DNA but I will try to explain the paper as best I can:
1. Contamination with other flora and fauna DNA 2. Relative low proportions of human DNA 3. The DNA is usually highly degraded, which limits the analyses to short read sequencing (in this case they used 76 bp reads). The halflife of human DNA is ~521 years.
To mitigate these problems they used multiple targeted approaches including one to isolate mitochondrial DNA, where they managed to sequence the whole ~16kb human mtDNA, where each base was covered by 62 sequencing reads on average (62x coverage).
They used another to isolate specific regions containing single nucleotide polymorphisms (SNPs), which are DNA mismatches known to be related to ancient human DNA and humans. They targeted 470,724 single nucleotide polymorphisms of which 70% (336,429) were recovered.
They did perform shotgun sequencing on all of the DNA isolated, but due to species assignment issues they again focused on fragments that contain diagnostic SNPs in these cases they only recovered a small number of SNPs per sample, again due to the relatively low proportion of human DNA and its degradation (20,526, 3,734, 124,862, 85,901, 34,756, 41,632, 34,677 and 72,992) as per the legend in figure 3.
That analysis makes me think of matching more than recovery.
"matching" is exactly how we do DNA sequencing right now. The current technology is called next generation sequencing (NGS), we multiply the DNA and perform matching digitally to construct the full DNA.
It's quite fascinating. It's like if order to figure out the shape of a teacup, we generate thousands of identical copies, smash them all to rather small bits, and then try to count the different types of shards as a first step to piecing together one full copy. Impressive that it works.
> It's like if order to figure out the shape of a teacup, we generate thousands of identical copies, smash them all to rather small bits, and then try to count the different types of shards as a first step to piecing together one full copy. Impressive that it works.
Yes, but you've got the order wrong.
The teacup is smashed before all of the identical copies are created.
(I wrote DNA analysis software for 6.5 years)
It's not fascinating; it's an endless source of trouble. We only do it because we don't have sequencers that produce extremely long (chromosome length) high quality reads, especially in sequences that contain a lot of repetition. This has been a source of errors and ambiguity for as long as we've used shotgun.
This is a great analogy. One small change is that there are two ways to reassemble it. One is to try to blindly put the pieces together and fork a teacup (read assembly) vs trying to use a picture of the teacup to figure out where the pieces go (read alignment / mapping)
Would it be possible to clone an ancient human being from DNA?
Probably not, not nearly enough material remained to make an accurate clone. The article mentions 70% recovery rate; according to the internet, humans share 98% of DNA with chimpanzees (and 35% with daffodils), so unless you have 100% or 99.9999% of the DNA, the clone will be imperfect at best and a Thing That Should Not Be at worst.
I think your ethical board would probably stop you first.
Keep in mind that this is survivorship bias. The vast majority of DNA from this period has lots. Sure, there is tons that exists but we haven't found but without a doubt almost all of it has been lost.
This is DNA that happened to be the right conditions to survive. It isn't so much that the medium is resilient but that if stored in the correct conditions it can survive.
It makes me think about how many ancient ruins don't exist simply because the people nearby didn't see reason not to reuse all that convenient unowned pre-quarried rock.
Even today, it's not a very compelling plea: "No, don't tear down the recently-abandoned building, it would look cool several hundred years after you die."
So too on the microscopic label, if there are convenient molecules nobody else is using...
"Spolia" is a fun architectural term for this sort of material reuse, particularly with the more interesting decorative pieces. Many of those stones taken from ancient buildings have become notable newer ancient buildings in their own right.
https://en.wikipedia.org/wiki/Spolia
> It makes me think about how many ancient ruins don't exist simply because the people nearby didn't see reason not to reuse all that convenient unowned pre-quarried rock.
In the case of Ostia near Rome, they mined it for building material until it became a malaria swamp. It wasn't drained until the 20th century. Around 20% of the workers draining the swap contracted malaria.
So this is how I should be storing family photos.
In a sense your DNA is your family photo.
I was going to say... except without that mole on your arm. But then I thought, it probably has all kinds of battle scars with disease and other adversity coded in it, making a mole inconsequential.
Thinking on how to save things long term is a fun exercise. If I were super rich and felt that highly of myself, I would totally build a monument to myself built to last the ages; elevated (against flooding), tonnes of erosion resistant rock, a library of all human knowledge in many different formats, sealed off. But with an exact copy near it for tourists.
You'd find yourself in company with many religious organizations. The Mormon Church has a couple of records vault carved into the granite outside SLC, while the church of Scientology has 3 geographically separated primary vaults dug into the mountains (Petrolia and Creston CA, and a place in the desert outside Albuquerque).
You’ve gotta have a series of timed vaults that give access to precious metals every few generations.
It’s even more impressive when you compare it to rna, which “lives” minutes. Take away the pair strand, add a hydroxyl group and a uracil, and it’s a totally different thing.
Im fascinated, any noob friendly reading material?
Honestly, scientific papers. The pain of jargon will be less than the pain of a popsci book. Especially with all the tools to rewrite/summarize/search these days.
Yes, but which ones? There are so many out there... It seems like you're educated on the subject, so you may be able to recommend good ones.
A good start would be the review articles listed here: https://scholar.google.com/scholar?q=rna+half-life&hl=en&as_.... If there's a paywall, use sci-hub or check the lab's page for a pdf. I should caveat that there is no one rna half life, some live much longer
It's ok if you don't have recommendations, but sending a google link is a bit out of pocket :(
Ha! I'm sorry. not trying to be cagey/dismissive. There's no paper that must be read: they're all nodes in a network. All I can do is point you to a cluster, w/ the right filter and jargon search terms. Apologies if I came off out of pocket.
Check out the review articles in the “Nature Reviews” journals, like “Nature Reviews Genetics”. These articles are written by experts but designed for a non-specialist audience (with undergraduate science education).
I think of the error correction codes used by CDs.
But for DNA, the data is needed to literally stay alive as replication occurs constantly through our bodies. And this has been refined over maybe billions of years.
When can I start storing passwords in mine?
You can order DNA sequences from all sorts of companies. IDT is by far one of the most popular, using classical biochemical means:
https://www.idtdna.com/pages/products/genes-and-gene-fragmen...
https://www.idtdna.com/pages/products/custom-dna-rna/dna-oli...
And a newer player that uses tech from integrated circuit manufacturing (I think?) is Twist Biosciences:
https://www.twistbioscience.com/twist-ordering-platform
Retrieval of information has a bit of latency, however.
Sooner than you'd think! https://wyss.harvard.edu/technology/dna-data-storage/
(though passwords aren't a great application)
Oh great when i get into old age not only will I forget my password but my DNA will have mutated to the point that it technically isn't my password any longer
lol
Why do you have all those eyeballs on your arm?
Oh, that... yeah, they said I had a lot of special characters in my LinkedIn password, and this is the best way to encode those.
You could likely store them in the junk DNA without much risk, as long as you avoid encoding sequences that are the start of coding regions. That said, if you managed to inject them into every cell of your body, this would be the biological equivalent of dropping pamphlets containing your passwords everywhere you go.
They require at least one emoji and an uppercase character
- Your password has expired. You must choose a new one.
- Uh, oh. How am I going to see behind me, then?
Might be a poor idea if anyone who can collect and sequence your DNA gets your passwords.
Yeah, you'd be vulnerable to pepper shakers and divulging all your passwords in a sneeze.
All of my passwords are encoded in pi…somewhere
Well, probably! But it hasn't actually been proven yet that pi is a "normal number" [0], though most mathematicians think it must be.
[0] https://en.wikipedia.org/wiki/Normal_number#
That's a stronger claim anyhow. We'd merely need Pi to be a rich number, ... which hasn't been proven either.
https://en.wikipedia.org/wiki/Disjunctive_sequence#Rich_numb...
It's not necessary that pi be normal in order for it to contain every possible sequence. Sufficient, but not necessary.
If the OP is anything like me, then they have no trust in number theory researchers and deliberately choose passwords like "141592" so they can be sure
I enjoy thinking about this. Not only is a sequence of digits encoding the complete works of Shakespeare in there somewhere, it's in there again. And again, an infinite number of times.
In my encoding I represent the works of Shakespeare by the digit 0, anything else by the digit 1 followed by its ASCII representation.
> The cool and dry conditions in the cave have made it possible for scientists to recover preserved DNA left behind by ancient Denisovans, Neanderthals and humans, all of whom occupied the cave at different times over 40,000 years.
That's a long time to have people live in a particular area generally, and a particular "home" in particular.
AIUI, some of the oldest writing we have dates to Ur III at 2000 BC, so that's 'only' 4000 years ago, or perhaps the Uruk period, which at 3500 BC, is 5500 years old:
* https://en.wikipedia.org/wiki/List_of_oldest_documents
* https://www.sfu.ca/~poitras/jesho_UR_14.pdf
So the oldest document(s) we have are only about 1/10th how long this cave was occupied.
Some of these time scales are mind-boggling.
Send that to a consumer DNA analysis company and find her closest living relatives!
It's basically everyone!
Or, it could be no one at all!
If you go back far enough (and I don't know if this is) isn't the answer always everyone or no one but never "some".
I know that person!
this is just the begining of DNA as a tool in archiology. Earlier work with densovian dna, showed not only a genetic profile,of indivuals, it showed a familial relationship, father/daughter. The implication is that we will start to get a clearer look into human migration patterns ,including tribal, and familial groups, which while interesting, will also be prone to every kind of abuse in the forwarding of various agendas,...racial,ethnic,religios, nationalistic. Makes me want to stir the pot sometimes, and feed back in a lurid interpretation of ancient DNA, proving, i dont know, how about our ancestors throwing off our alien overlords, but now the death star has activated and is beaming alien DNA data right into us from the 5G, but, but, (marketing angle), ....eating , "product xx" or product xy, strengthens your imune system and prevents the alien download from finishing. The real issue in my blathering, is that fiction is fighting an uphill battle, to be stranger than reality.
I thought that it was already established that we're descendant of the ancient astronauts from the 12 Colonies of Kobol, and that the "mitochondrial Eve" was a child of a human and a Cylon.
(Part of me wishes to see this resurface as a bona fide religion, oblivious to the source material.)
All of this has happened before, and all of it will happen again.
How did they know to explore this cave in particular? Blows my mind. Or was it by accident?
Denisova cave has been known for about 150 years or so. Back in the 1970s, the Soviet Union sent some archaeologists out to see what was in the cave. They found some upper paleolithic stuff (e.g. like what the article is about), as well as some mousterian stuff (very weird this far north and east). They did excavations over the next couple of decades and eventually, some of the dating/sequencing technology improved to the point where it could actually be used on the cave artifacts. That's when they discovered denisovans and immediately made the cave one of the most important archaeological sites on the planet. There's been no lack of funding since.
...and also showed that she had antlers.
(Sorry, I couldn’t resist)
[flagged]
It says a lot about the state of discourse and gender science that I can't tell if you genuinely don't understand or if you are being facetious.
But assuming you are being genuine: your sex (faka gender) is encoded in your DNA on the 23rd chromosomal pair. If you have two X chromosomes (XX), you are a female human (woman). If you have one X and one Y (XY), you are male human (man). These chromosomes dictate your sexual development (organs/hormones/etc). There are some people (estimated at 1-2% of the human population) who are "intersex", in that they don't have an XX or XY pair, but some variation thereof (XXY, XYY, etc). However even these variations generally fall under one or the other umbrella of male or female. e.g. Klinefelter syndrome (XXY) is generally going to present as male (albeit frequently with poorly developed testicles and other complications). Genes are complicated so this is a bit of an oversimplification.
To make this more about sex itself (since humans are a sexually reproducing species and that is why we are having this conversation at all), there are effectively three options for all humans: you produce small gametes (sperm / male) or you produce large gametes (eggs / female), or you produce neither due to some complication and therefore cannot participate in procreation. This is dictated almost wholly by your DNA.
So, back to the article: they know the DNA in the deer tooth was from a woman because (presumably) the 23rd chromosome was an XX pair.
Just to add one more wrinkle to the link between DNA and the presentation of sex, there is also androgen insensitivity syndrome, in which the person has a Y chromosome, but the developing body does not react to the testosterone produced by the testes.
The result is someone who may appear to be female, have female genitals, but has testes where ovaries would be expected. It's often not discovered until puberty doesn't happen as expected, and they discover they can't have children.
Like all these conditions, this is on something of a spectrum depending on how total it is.
As you say, genes are complicated. So much more so than is often implied in reporting of discoveries of "a gene for X".
DNA has a very strong signal for man, woman, and everyone in between.
I was a little blithe with my reply here, and feel bad about the scientific inaccuracy I'm perpetuating. The "everyone in between" spectrum often has strong signals, but sometimes it's not very strong straight from DNA alone! And it's also incredibly complex, far far more complex than doing mutation calls, to the point that automating it is quite difficult. Sure, finding XX, XY, XXY, and the many other combinations of sex chromosomes as they appear in nature is easy. Finding subtle inactivations of the genes on the Y chromosome is much harder. In fact analysis of genomes of intersex people is a common use of consumer whole genome and whole exome sequencing, so any consumer sequencing company that simply reports XX as female and XY as male is laughably amateurish, and your customer support lines will be swamped with extremely knowledgeable self-educated intersex people that will being providing tons of information for the company to up their game.
> so any consumer sequencing company that simply reports XX as female and XY as male is laughably amateurish
To my knowledge there is no XX person who can produce sperm and there is no XY person who can produce eggs. So while "XX is female" is over-simplified, "XX is not male" seems fairly clear.
> your customer support lines will be swamped with extremely knowledgeable self-educated
In no other field this combination (self-educated, actually knowledgeable, and calling customer support) seems to exist, so that alone might be worth further study.
They are highly motivated people trying to understand the genetic basis of themselves better, and have usually been seeing doctors throughout their lives towards that end, and usually they'll know more than their doctors because of the rarity of their phenotypes. I have tons of respect for that.
> "It was clear that a human handled it…”
Ah, science.
My first thought, after reading the headine, was that the deer bit her.
We have vastly different experiences with deer I suppose.
It's like IT, gotta make sure you have the basics right like whether it's plugged in before you start with more advanced stuff.
There actually was human DNA in it so I don't know why we're scoffing as successful methods as if they're unreasonable.
The article says that it belonged to a species of deer called “wapiti”. Since I never heard of it, I looked it up and it’s just an elk. Why didn’t the article just say “elk” which is the much more common term?
Two reasons:
- Elk is ambiguous. There's an Elk/Wapiti in North America, Central Asia, and East Asia, and another species of deer referred to as an "Elk" by people in Eurasia, but which is known as a "Moose" in North America.
- Because journalists these days don't have time to look these kinds of things up. The original paper only refers to it as wapiti/cervus canadensis/deer. If the whoever wrote that article knew it refers to an elk, they'd have pointed that out for the reader.
Elk is pretty ambiguous — it refers to different species depending on the context (in Europe, ‘elk’ refers to what in north America is called a moose. Wapiti is a name for what ‘elk’ refers to in North America). You get a similar problem with the words ‘hawk’ and ‘buzzard’
And badger -- In Europe they are small adorable members of the Meles genus. In the Americas, Africa, and Asia the word refers to larger and more aggressive animals in the Taxidea and Mellivora genera that just look superficially like Meles.
The wapiti is the animal on the reverse of the Canadian 25 cent definitive coin. Perhaps the folks who write the article are just educated and worldly.