If its an exponential decay process, as it supposedly is, then its more of a statistical game where the median helix would have cracked into 1 base pair at 6.8Myr.
That would really suck if you only had one single helix to work with. However I'd think theoretically given an infinite amount of genetic data (unlikely) you could analyze every molecule in the sample separately and then put it back together.
There's a radiation analogy... if you've got a speck of Co-60 of a certain almost infinitely small size, its not too hard to do the math to prove that after 1M years theres less than one atom left of Co-60. Say you want a 1 Kg pile of Co-60 thats 1M years old. Yes, indeed, it is very true that if you start with exactly and only one speck of Co-60 the odds exceed 50% chance that there will be less than one atom left. The solution is simple, start with a bigger piece than an infinitely small speck and use a lot more than one speck.
This isn't a silver bullet, being exponential, if I were not so lazy I could work out that if you wanted the DNA from the first known life on the planet, you'd need a multiple of the entire mass of the universe as a starting sample size or something crazy like that.
Just saying if you want 6.80001 Myr DNA its not impossible its just going to be a huge expensive PITA compared to existing techniques for stuff merely 100 years old.
The guy who divided 6.8e6/521 I think is trying to tell you how many base pairs long an average DNA helix probably would be, I think, sorta? So the average 1/2 life of a base pair is 521 years, and half of an entire helix is 6.8M years.
"Just saying if you want 6.80001 Myr DNA its not impossible its just going to be a huge expensive PITA compared to existing techniques for stuff merely 100 years old."
That's kind of an interesting problem. I wonder how much material you'd need to get decent coverage of a averaged sized organism (few gigabases) given the decay rates they calculated.
That would really suck if you only had one single helix to work with. However I'd think theoretically given an infinite amount of genetic data (unlikely) you could analyze every molecule in the sample separately and then put it back together.
There's a radiation analogy... if you've got a speck of Co-60 of a certain almost infinitely small size, its not too hard to do the math to prove that after 1M years theres less than one atom left of Co-60. Say you want a 1 Kg pile of Co-60 thats 1M years old. Yes, indeed, it is very true that if you start with exactly and only one speck of Co-60 the odds exceed 50% chance that there will be less than one atom left. The solution is simple, start with a bigger piece than an infinitely small speck and use a lot more than one speck.
This isn't a silver bullet, being exponential, if I were not so lazy I could work out that if you wanted the DNA from the first known life on the planet, you'd need a multiple of the entire mass of the universe as a starting sample size or something crazy like that.
Just saying if you want 6.80001 Myr DNA its not impossible its just going to be a huge expensive PITA compared to existing techniques for stuff merely 100 years old.
The guy who divided 6.8e6/521 I think is trying to tell you how many base pairs long an average DNA helix probably would be, I think, sorta? So the average 1/2 life of a base pair is 521 years, and half of an entire helix is 6.8M years.