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Half-Life of DNA is 521 Years, Jurassic Park Impossible After All
another random user writes with this quote from Nature News:
"Few researchers have given credence to claims that samples of dinosaur DNA have survived to the present day, but no one knew just how long it would take for genetic material to fall apart. Now, a study of fossils found in New Zealand is laying the matter to rest — and putting paid to hopes of cloning a Tyrannosaurus rex (abstract). After cell death, enzymes start to break down the bonds between the nucleotides that form the backbone of DNA, and micro-organisms speed the decay. In the long run, however, reactions with water are thought to be responsible for most bond degradation. Groundwater is almost ubiquitous, so DNA in buried bone samples should, in theory, degrade at a set rate. Determining that rate has been difficult because it is rare to find large sets of DNA-containing fossils with which to make meaningful comparisons. To make matters worse, variable environmental conditions such as temperature, degree of microbial attack and oxygenation alter the speed of the decay process. By comparing the specimens' ages and degrees of DNA degradation, the researchers calculated that DNA has a half-life of 521 years. That means that after 521 years, half of the bonds between nucleotides in the backbone of a sample would have broken; after another 521 years half of the remaining bonds would have gone; and so on."
So in amber, or some other similar impermeable substance, the chemical reactions requiring water or air might well be prevented or dramatically slowed, thus the degradation of DNA might be substantially slower than the 521 years described in the summary.
Not necessarily the end of the Jurassic Park idea.
If the Government becomes a lawbreaker, it breeds contempt for law;
If the half-life of DNA is 521 years how are scientists able to sequence 30.000 year old Neanderthal DNA? Presumably this applies to regular DNA, did Svante Pääbo and his team sequence mtDNA?
Only to idiots, are orders laws.
-- Henning von Tresckow
Cryogenics would pretty much stop most of the reactions that break the bonds, so half-life would be hugely increased, especially if material is properly dried first. Seeds can last for many decades and still grow if dried to 5% moisture content and frozen at -80. Not sure about animal embryos, but sperm and eggs also.
Korma: Good
If you don't pay for your putting, you can't have any meat. How can you have any meat if you don't pay for your putting?
Why do they need to know? 10,000 years is roughly 20 half-life periods, so they should expect roughly 1-millionth of the DNA to remain.
Since the wooly mammoth genome is approximately 4.7 billion in 58 chromosomes, for an average of 81 million base pairs per chromosome, the DNA fragments would be, on average 81 base pairs long, which should be enough to figure out the original sequence after duplicating and matching. So a full reconstructed mammoth genome should be possible.
He meant frogs not "frog's". Dino DNA is of course really large (Were talking a T-Rex afterall), so all they have to do is inject a whole frog directly in sequence. AAAATSAATTTTS(frog)AAA
Heck, 81 base pairs would save you a lot of time chopping strands for PCR, you would already have the pieces. :)
Seriously though, given those numbers are for a single cell, how many do you have with a mammoth carcass? More than 1, in fact more than 1 million. If you can find a lab blender big enough to stuff a mammoth carcass in to, the rest should be trivial. I would also venture that after a while, the fact that a dinosaur bone didn't degrade to dust means that it is better preserved than your average thing stuffed in to the ground so the half life would, after a point, extend.
Given a few dinosaur samples, you could probably get enough to reassemble most of the genome. With some not all that complex math, you can compare it to a few key reptile sequences and likely get some strong hints or even direct sequences that are missing. Some things change a lot over time, others do not or can not.
And yes, I did do this in college. No, not on dinosaurs though, that would have been a bit more fun to talk about at the bars.
-Charlie
Something must be wrong with the 521 years. 65 million years / 521 years = 124.760 half lifes.
That means only 1 / (2^124.760) = 1 / (3,1787695069134767997232294562089e+37556) of the original DNA should be available for analysis today. Those guys would be lucky to find a single base pair that has not decayed. Hardly a sufficient basis to make a quantitative analysis ;-)
C - the footgun of programming languages
The half-life of unusual British phrases in the US is less than 18 years.
Even more importantly, this ignores a previous published article on "DNA Sequence from Cretaceous Period Bone Fragments" -- Science 266 (5188) 1229-1232, here is a PDF of the article in Science. Either 80 mya (Cretaceous) is horribly wrong, the 521 year half-live of DNA is horribly wrong, Woodruff, et al were horrible deceived (or frauds) or some combination of these.
You would hope evidence would be the deciding factor, but scientists are human too, and the interpretation of evidence is often more important than the actual evidence -- it is very hard to upset to prevailing opinion (as it should be when the opinion is well founded)
521 years should be enough for anybody.