How long does DNA last?
Human DNA has been recovered from a Neanderthal fossil 70,000 years old. That’s a record, but there may be plenty of DNA recoverable from a human body 10, 50 or even 150 years after death. The bodies of the Romanov royal family, executed during the Russian revolution, were identified from DNA comparison in the last decade. US scientists recently confirmed the death of the outlaw Jesse James after they exhumed a disputed corpse. Time, says Mark Thomas, a forensic anthropologist at University College London, is not really the problem, even in the tragic circumstances of the Indian Ocean tsunami. The technique of DNA sampling is less than 20 years old, but has become standard practice the world over. Standards, however, are not quite the same the world over, which may be why a Japanese forensic delegation has announced that it will re-examine all the bodies originally handled by Thai experts, why China has offered to collate the data, why a US team has announced that it will handle the sa
DNA is degraded in cells via DNAses which break the bonds in the DNA. DNAses require Mg (magnesium) as a co-factor in order to work so if there is no Mg available the DNAses cannot breakdown the DNA. Products like InstaGene are used to preserve DNA in this manner so the DNA can be used later. Other conditions, such as water availability, bleach and other chemicals, and desecation level will also damage DNA. Assuming none of these factors are present DNA could last a very long time (>1000 yrs), but it is very unlikely that this would occur.
