Submitted by Memer9456 t3_yucg54 in askscience
I wasn't sure whether to mark this as chemistry, biology, or paleontology.
Comments
reddit455 t1_iw98l6v wrote
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frozen mammoth tissue.
https://en.wikipedia.org/wiki/Yuka_(mammoth)
Yuka is the best-preserved woolly mammoth (Mammuthus primigenius) carcass ever found. It was discovered by local Siberian tusk hunters in August 2010.[2][3][4]
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dodos didn't live anywhere near ice (cold part of earth).. bugs ate all the dead ones.
https://en.wikipedia.org/wiki/Dodo
The dodo (Raphus cucullatus) is an extinct flightless bird that was endemic to the island of Mauritius, which is east of Madagascar in the Indian Ocean.
Dimako98 t1_iw98s5z wrote
Are you sure that's what they're asking? Pretty sure they mean how do we have more wooly mammoth DNA than dodo DNA as in, how do we know more of their genetic code?
In which case it's as issue of preservation, since wooly mammoth remains are often frozen in the tundra, whereas dodo birds lived in a tropical climate which does not lead to good preservation of organic remains.
deadmeatsandwich t1_iw99axc wrote
I think the OP means just the DNA samples of the species alone, and not contained within a human genome.
It’s not just when the two species died, it’s also a factor of where/how they died. Mammoths are from cold arctic regions, and many of them died and have been encased in permafrost, which is essentially a natural freezer which helps preserve any samples.
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Fluapaveggen t1_iw9asn8 wrote
Because a lot of whole wolly mammuts have been preserved in tundra. Not only are they frozen and thus won't decompose, but the dense clay they're ofte covered with prevents oxidation aswell as preventing them from drying out. They are basically frozen solid and then vacuum packed.
The dodos lived in relatively hot areas and thus would decompose within months.
[deleted] t1_iw9d62o wrote
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rsc2 t1_iw9qh99 wrote
What about museum specimens?
EngFarm t1_iw9rzuv wrote
Supposed stuffed dodos seen in museums around the world today have in fact been made from feathers of other birds, many of the older ones by the British taxidermist Rowland Ward's company.[107]
deadmeatsandwich t1_iw9shli wrote
Any specimen that is going to be for display, is pretty much just skin and feathers on a stuffed framework. It will have likely been treated with harsh chemicals in order to preserve it, which will destroy any DNA beyond use.
PM_Me_Ur_Fanboiz t1_iwaa05u wrote
Oxygen. Specimens trapped in ice or tar or are quickly engulfed in a muddy river bank are sealed in an airtight tomb where things that would decay them can’t reach. Namely oxygen to fuel bugs. So, they sit.
Things that die in a warm/wet climate crawling with trillions of insects and scavengers won’t last a few hours.
We know so much about the past largely because bad things happened a lot. There were at least five mass extinction events that nearly killed everything. Those are easy to find if you dig in the right spot. Harder to identify and locate are the isolated events of mudslides and flash floods and so on. With that in mind, when digging, you want to locate the layer of dirt relative to your timeframe and root around in it. If you’re looking for a needle in a haystack, you’ll rarely find it. If you’re looking for a planet killing event, you’ll find that layer easily, AND the specimens trapped under it. So, paleontologists spend a lot of their very valuable time digging easy and well known places like the black hills, or riverbanks in Canada. Because of all that, we have lots of fossils from specific eras and almost nothing from others.
[deleted] t1_iwait1w wrote
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a_weak_child t1_iwao0n3 wrote
Most the comments on here are misunderstanding your question. To actually answer your question: it’s because wooly mammoths are much closer to us on a phylogenetic tree than dodos are. Dodos are birds, a closer ancestor to them is the dinosaurs. Wooly mammoths are mammals, and all mammals share a TON of DNA in common. This is why we find so many mammals so cute too :). Look up the phylogenetic tree!
[deleted] t1_iwaobaq wrote
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akeean t1_iwapdsu wrote
You'd need ~500x the museum specimen of dodos to get even remotely close to a single mammoth find in mass.
akeean t1_iwapfy3 wrote
Dodos were small & Mammoths were huge.
Then with size also comes benefits on how much impact surface decay has, not to mention that Mammoth carcasses can be found in vast areas with climate and geology that helped to conserve it near indefinely (though not for long anymore, thanks to global warming), while the other lived in a small area with climate&conditions awful for conservation.
waylandsmith t1_iwat4ne wrote
I'm pretty sure you've misunderstood. I can see there being some ambiguity from the wording of the question, but the topic flair on the question is "paleontology", not "genetics" or "biology". I think it's safe to say they're asking about "having" DNA in the sense of having samples from it, not "having" DNA as in sharing DNA with those species.
LearnedGuy t1_iwayskr wrote
And dodos don't have teeth as a DNA source.
Admetus t1_iwazhnj wrote
Could all damaged DNA be sort of correlated to find the correct DNA sequence? Or did the chemicals break DNA chains to a point beyond recognition?
Ooh found the DNA 🧬 emoticon lol
[deleted] t1_iwazl1u wrote
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bellyflop111 t1_iwb2p0z wrote
How long ago a species went extinct has nothing to do with DNA it’s all to do with adaptability. When the ice age came to an end mammoths couldn’t adapt to the new environment and went extinct. Just like how Neanderthals went extinct but we share more DNA with them than chimps or bonobos.
[deleted] t1_iwb8bmf wrote
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EntangledPhoton82 t1_iwb8cw4 wrote
Suppose you found pieces a c t g… How could you know if the correct order is actg, atcg, agct,… ? It would be virtually impossible.
cowbirdy t1_iwbhtjp wrote
This is true of old bird study skins which often used arsenic to prevent bugs from eating them, but modern study skins don't use any harsh chemicals in the preservation process - just cotton and sunlight. Sometimes dawn dish soap will be used if the skin is particularly dirty.
Also even historical bird skins don't tend to have large amounts of arsenic on the foot pads which is where DNA is often sampled from due to its thickness and its remarkably successful compared to other taxa. Though the addition of arsenic does inhibit PCR success,its not found at a particularly high volume on the feet of historical study skins.
Here's a link to one reference, but I'm also just speaking from experience preparing study skins and picking up info from there.
This isn't to contradict the fact that there is less dodo DNA than mammoth - but preserved bird skins are some of the easiest to extract DNA from, compared to ethanol preserved specimens (common for herps and insects) and mammalian taxidermy.
I think your point from another comment about how mammoths were essentially frozen is the primary reason that there is more usable DNA.
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Fuzzylogic1977 t1_iwbqapa wrote
Dodos were apparently delicious. They were easy to hunt and they were hunted and eaten to extinction. The very few specimens left (3 according to a previous commenter) are of poor quality. Mammoth carcasses have been frozen in ice or “bogs” and in those cold low oxygen environments the specimens have been able to be very well preserved.
Tuga_Lissabon t1_iwbs39d wrote
Whooly mammoths were considerate enough to die in tundras. They froze and got covered up in ice. Many are being taken out of the ice entire, with meat attached. You can now even get a mammoth steak if you could stomach it.
The Dodos were captured by passing ships, eaten, and ended up buried at sea after a sailor took a dump over the railing.
Chickengilly t1_iwbtxuh wrote
Oops. Sorry. I thought you were asking why our dna is composed of more… yada yadda
The13thReservoirDog t1_iwbvmvd wrote
Dodo’s were a small population found only on a 1 single tropical island where its too hot for corpses to be preserved
mammoths were widespread and their habitat was mostly cold frozen tundra for most of the year
perfect for preserving remains
mrlazyboy t1_iwbwx04 wrote
There’s so much frozen mammoth that you can actually buy mammoth tusk for reasonable prices
Hotarg t1_iwc0mx8 wrote
Take a newspaper, put it in a blender, run it on smoothie for a minute. Now tell me the sports scores.
mrbananas t1_iwc146g wrote
The last dodo specimen was thrown into a furnace. Only the head and foot were saved before completely being burned
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atomfullerene t1_iwcnb5t wrote
Until recently, museums weren't particularly trying to preserve DNA. Sometimes you can get DNA from museum specimens, but they aren't specifically great for it (still better than nothing, though).
But for dodos specifically, there are only 2 or 3 specimins in the world that were collected when the species was alive, and only one of those has any soft tissue
https://blogs.ucl.ac.uk/museums/2013/09/19/the-best-natural-history-specimen-in-the-world/
lookmeat t1_iwcr0ks wrote
Yup, the thing is, even with preserved you still have to contend with the natural decay of DNA. It's a half life of 521 years. This doesn't mean half the DNA is gone, but half the bonds. So after a couple centuries all you'd see are a bunch of pieces of DNA that you have to, somehow, assemble in the right order, that's a puzzle on a different level. The only way to slow down there process is to freeze which, Uber right conditions, can extend the half life by thousands of years.
Also wooly mammoths are not that old. The pyramids where built when there where still mammoths. But that depends what mammoth we are talking about.
And that's the other reason. When we talk about mammoths, we are talking about many species, that lived across all the north of America and Eurasia for around 5 million years. When we talk about dodos, it's a species that only lived in an island (not Madagascar but way smaller Mauritius) over who knows how long (their branch splits 25 million years ago, but they are so different from their closest relative species that it's hard to define when the actual dodo, vs predecessor species, evolves) but it may not be that much. So the chances that you have pieces of dodos that happened to be in a place that preserve them well enough is much lower than that of any mammoths'.
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MansfromDaVinci t1_iwdauqh wrote
mammoth ivory has been a major source for centuries, there's so much frozen mammoth people used to eat it as a delicacy
mrlazyboy t1_iwdh8mr wrote
I actually got a custom chefs knife made and the handle is mammoth tusk
Traditional_Bend_225 t1_iwdhcw1 wrote
Birds have a lot more lighter, fragile skeletons that dont usually hold up over centuries. We have much larger fossil records for animals with bigger, thicker, skeletons because they can survive the elements over time.
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MegavirusOfDoom t1_iwtcjgb wrote
Warm-bodied ties between mammals and birds diverged 300mn years ago. When your mummy was still in the womb :)
December 13, 2021
University of Queensland
The evolutionary origin of endothermy (the ability to maintain a warm body and higher energy levels than reptiles), currently believed to have originated separately in birds and mammals, could have occurred nearly 300 million years ago. Share:
FULL STORY
Rodents and elephans split 130mn yra ago. Elephants and dogs split 110 million... mammals and dodos split 250 300 million years ago.
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