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barathvaj barathvaj
wrote...
Posts: 239
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12 years ago
If a body is buried before 3000 years ? Can make Dna samples?
if a body is burned , there is any chance of getting the DNa samples?

explain how and from what source it can b taken?
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6 Replies
~Bv ram~I'm a student for all those who teaches
Replies
wrote...
Educator
12 years ago
If a body is buried before 3000 years ? Can make Dna samples?

Yes, but only if the source of the DNA (such as the animal flesh, for instance) has been preserved (is frozen, or has been submerged in ice since it died).

if a body is burned , there is any chance of getting the DNa samples?

No, DNA is a delicate molecule that doesn't require must heat to get destroyed.

Hope this successfully answers your questions, barathvaj.
barathvaj Author
wrote...
12 years ago
Yes!,But i heard DNA samples can be taken from bones?
And if body is burned using teeth ,DNA samples can be made? this is fake or true?
~Bv ram~I'm a student for all those who teaches
wrote...
Educator
12 years ago
But i heard DNA samples can be taken from bones?

Very difficult to do such a thing because fossilized both are often poor quality, and their DNA is contaminated.

Freezing provides the ideal preservation conditions. The most widely accepted oldest DNA yet isolated comes from 400,000-year-old plants found in ice in Siberia. But most specimens are not excavated from such places.

An improved technique for retrieving DNA from fossil bone, just published in the journal Proceedings of the National Academy of Sciences (PNAS), may help.

Dr Michal Salamon, from the Weizmann Institute of Science in Rehovot, Israel, and colleagues, showed that "crystal aggregates", small mineral pockets formed during fossilisation, can preserve DNA better than the rest of the bone.

They compared DNA extracted from these crystal aggregates with genetic material taken from untreated, whole-bone powder. The samples were taken from eight different modern and fossil bones.

They found better preserved, less contaminated DNA could be recovered from the isolated crystals.

This approach, "significantly improves the chances of obtaining authentic ancient DNA sequences, especially from human bones", they told PNAS.

Commenting on the latest research, Dr Michael Hofreiter, from the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, who helped decode 40,000-year-old nuclear DNA from a cave bear earlier this year, said: "It's possible; but there need to be more studies on more samples, and they need to show that you don't get human contamination of animal bones.
barathvaj Author
wrote...
12 years ago
Crystal pockets are made by nature during fossilisation which preserves the DNA ,right?

Did You know anything about what that mineral pocket is composed of and how it works in preserving DNA?

Is it same when teeth is preferred for taking DNA sample?.I mean if teeth is also fossilized by mineral pockets, DNA sample is possible?
~Bv ram~I'm a student for all those who teaches
wrote...
12 years ago
bio man: quite confusing answers!?!

If a body is buried before 3000 years? Can make Dna samples? Answer is definitively YES, but the success depends on many factors. These are e.g. surrounding temperature, pH of soil, moisture (water), microorganism infestation, body part/tissue you are sampling, type of DNA (mt or nuclear)... Based on theoretical and empirical data the time limit today is about 1 mil. years. Please forget dinosaur DNA or something like that (hope you know that).   
if a body is burned, there is any chance of getting the DNa samples? YES, there are quite a lot of cases. DNA can be obtained from bones and also teeth. BUT!!! with increasing duration time and temperature the amount of retrievable DNA is rapidly decreasing. it is quite challenging even in forensic cases and archaeological samples are even more tricky. But cooked bones can be very good source of DNA.
If you are not an ancient DNA specialist forget the work of Salamon (and it is not "just published", it is from 2005!). That method is not in wider use and it can be counterproductive (losing a lot of DNA molecules)
Prefering teeth to bones can be also tricky (esp. in archaeological samples), sometimes it is better to sample normal compact bone.
Answer accepted by topic starter
bio_manbio_man
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12 years ago
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