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Homology studies. A DNA strand 17 bp long is pretty distinct. If a strand that long or longer was found, we would gain a lot of information about the evolutio

Homology studies. A DNA strand 17 bp long is pretty distinct. If a strand that long or longer was found, we would gain a lot of information about the evolutionary history of dinosaurs that we could never get from fossils. However, the article isn't clear about what they found. It says DNA, then it says there may not be a recoverable sequence. In that case nucleic acids would be a better term than DNA. Without more info on what stain they used to identify the "DNA", the implications of this research are hard to figure out.

roywiggins 6y ago
"broken down components" reads like loose nucleic acids to me, rather than actual DNA fragments
- deleted 6y ago
  [deleted]
crimsonalucard 6y ago
I think by what "good does that do?" he means like what's the point if you can't use it to create dinosaur clones Jurassic Park style. I literally clicked on the link because that was the only thing on my mind. Not joking.
- Robotbeat 6y ago
  Even this amount of genetic material is a fantastic find, though. Maybe there's hope of some future technique being able to recover short sequences somehow.
- roywiggins 6y ago
  I mean that a soup of loose nucleic acids can't be sequenced even if we wanted to, we can't learn anything about their genome unless there's actual intact lengths of DNA. That quote implied the former to me, so- there's not much to be learned from just nucleic acid soup
burtonator 6y ago
There was a paper not long ago saying that the DNA half life is about 500k years or so and that most of the DNA would be degraded. The issue I had with this is why can't we reassemble chunks of DNA like we can with a puzzle. I'm certain specialized algorithms exist within DNA analysis for this reason. This isn't my field and there are already algorithms that exist on the top of my head that could solve this issue. The main issue is that you'd have to find a LOT of DNA to build one complete strand and you wouldn't have one strand from one specific animal. ... but you'd have a rough picture.
- daemonk 6y ago
  That's pretty much how modern genome assemblies work. We currently do not have a reliable or accurate way of sequencing DNA longer than ~200 bases. So we fragment the DNA into small pieces, sequence them and then put it all back together. It's not a completely solved problem as there are features of genomes that can make this process difficult or complicated (repetitive regions, highly heterozygous organisms, etc). Especially with short sequences. We have technology right now that can allow us to sequence long fragments, but at lower quality and accuracy. There are a lot of tools out there that uses the longer, but lower quality sequences to scaffold the shorter, higher quality sequencing data.
  - haihaibye 6y ago
    Illumina sequencers (highest throughput per $) have a (paired end total) read length of 300 but we can sequence much longer with other tech. Ie Pacbio - 10-15kb Sanger sequencing, used for the human genome project 20 years ago is over 500 bases
- jessriedel 6y ago
  That's the halflife of each bond between nucleotides. After one tenth of a half life you're left with strands of average length ~20 nucleotides. After a full half life they are of length ~2, i.e., mostly just scattered GCs, ATs, etc. After several half-lives, it's almostly completely single nucleotides, and the chance that there are any surviving strands longer than a given length N falls exponentially in time and N.
bosswipe 6y ago
What they found is structures that looked like cells under a microscope: https://academic.oup.com/view-large/figure/200008005/nwz206fig1.jpg https://academic.oup.com/view-large/figure/200008005/nwz206f... Section C shows cell-like structures and D shows the hypothesised DNA-like structure. They compare with a modern Emu's microstructures in section G. They also applied a stain to the fossil and compared it to a stained emu bone here https://academic.oup.com/view-large/figure/200008014/nwz206fig2.jpg https://academic.oup.com/view-large/figure/200008014/nwz206f...

roywiggins 6y ago

"broken down components" reads like loose nucleic acids to me, rather than actual DNA fragments

deleted 6y ago
[deleted]

crimsonalucard 6y ago

I think by what "good does that do?" he means like what's the point if you can't use it to create dinosaur clones Jurassic Park style. I literally clicked on the link because that was the only thing on my mind. Not joking.

Robotbeat 6y ago
Even this amount of genetic material is a fantastic find, though. Maybe there's hope of some future technique being able to recover short sequences somehow.
roywiggins 6y ago
I mean that a soup of loose nucleic acids can't be sequenced even if we wanted to, we can't learn anything about their genome unless there's actual intact lengths of DNA. That quote implied the former to me, so- there's not much to be learned from just nucleic acid soup

burtonator 6y ago

There was a paper not long ago saying that the DNA half life is about 500k years or so and that most of the DNA would be degraded. The issue I had with this is why can't we reassemble chunks of DNA like we can with a puzzle. I'm certain specialized algorithms exist within DNA analysis for this reason. This isn't my field and there are already algorithms that exist on the top of my head that could solve this issue. The main issue is that you'd have to find a LOT of DNA to build one complete strand and you wouldn't have one strand from one specific animal. ... but you'd have a rough picture.

daemonk 6y ago
That's pretty much how modern genome assemblies work. We currently do not have a reliable or accurate way of sequencing DNA longer than ~200 bases. So we fragment the DNA into small pieces, sequence them and then put it all back together. It's not a completely solved problem as there are features of genomes that can make this process difficult or complicated (repetitive regions, highly heterozygous organisms, etc). Especially with short sequences. We have technology right now that can allow us to sequence long fragments, but at lower quality and accuracy. There are a lot of tools out there that uses the longer, but lower quality sequences to scaffold the shorter, higher quality sequencing data.
- haihaibye 6y ago
  Illumina sequencers (highest throughput per $) have a (paired end total) read length of 300 but we can sequence much longer with other tech. Ie Pacbio - 10-15kb Sanger sequencing, used for the human genome project 20 years ago is over 500 bases
jessriedel 6y ago
That's the halflife of each bond between nucleotides. After one tenth of a half life you're left with strands of average length ~20 nucleotides. After a full half life they are of length ~2, i.e., mostly just scattered GCs, ATs, etc. After several half-lives, it's almostly completely single nucleotides, and the chance that there are any surviving strands longer than a given length N falls exponentially in time and N.

bosswipe 6y ago

What they found is structures that looked like cells under a microscope: https://academic.oup.com/view-large/figure/200008005/nwz206fig1.jpg https://academic.oup.com/view-large/figure/200008005/nwz206f... Section C shows cell-like structures and D shows the hypothesised DNA-like structure. They compare with a modern Emu's microstructures in section G. They also applied a stain to the fossil and compared it to a stained emu bone here https://academic.oup.com/view-large/figure/200008014/nwz206fig2.jpg https://academic.oup.com/view-large/figure/200008014/nwz206f...