> 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
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.
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.
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)
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.
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...
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.
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.
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.
(though passwords aren't a great application)
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.
- Uh, oh. How am I going to see behind me, then?
https://en.wikipedia.org/wiki/Disjunctive_sequence#Rich_numb...
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.
(Part of me wishes to see this resurface as a bona fide religion, oblivious to the source material.)
(Sorry, I couldn’t resist)
Ah, science.
- 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.