‘Oldest’ DNA—an exciting find!
DNA is the ‘molecule of heredity’ found in all living things—a complex, long-chain molecule on which is written a specific code. This code does not reside in the chemical properties of DNA, but must be ‘written’ on it by the sequence of ‘letters’ by which it is constructed. When the DNA specifications within any living organism are ‘translated’ by the machinery of living cells, this code specifies, like a blueprint or ‘recipe’, what the finished product (such as you) will be like.
The relentless tendency of complex molecules is to break down into simpler molecules. Because this is so well known and because it happens so quickly, scientists do not as a rule expect to find DNA (or other complex molecules, such as the proteins haemoglobin and collagen) in long-dead specimens. As mentioned in a previous Creation magazine (11(4):50), the opinion of a well-known forensic scientist is that traces of blood protein, for instance, left in damp soil would be gone within days, weeks or months at the most. This is due not only to normal chemical breakdown, but also to bacterial attack.
Under certain conditions, for example the chemistry of a peat bog, this breakdown is greatly retarded. Thus, it is no surprise to find humans who were buried in peat bogs, even centuries ago, to be beautifully, almost eerily preserved.
A peat bog specimen of human brain (assumed by evolutionists to be 7,000 years old, but certainly many centuries, perhaps even 1,000 to 2,000 years old) has yielded a fragment of DNA from which one can make copies, thus allowing one to study the details of its sequence. (Human ingenuity has been able to utilize some of the chemical techniques by which living cells make copies of DNA.)
A fragment of DNA from a now-extinct ground sloth is also known, but was too poorly preserved to analyse properly in this way. However, the ‘age bracket’ given for this sloth specimen (13,000 years) is very difficult to accept, given the biochemical facts of the rapid breakdown of DNA.
‘Fossil’ magnolia leaf DNA
There has been another discovery of a fragment of ‘fossil DNA’ in sufficiently good condition to be able to make copies from. Not in a peat bog, but an ordinary clay rock.1 Inside the rock was found a well-preserved, though crumbly, magnolia leaf, from which the DNA (about 820 bases long) was extracted. What makes the find so extraordinary is that, according to radiometric dating of surrounding sediments, the leaf is regarded as 17–20 million years old!
Think for a moment about traditional beliefs of fossils being formed by slow and gradual processes—in this case, a leaf falling into an ‘ancient lake bed’. It will, of course, most likely rot away unless rapidly covered. So the existence of countless billions of well-preserved fossils around the earth denies the very philosophical basis (slow and gradual) on which the whole age-dating and evolutionary scheme was initially constructed.
A much more satisfactory explanation is that such fossils were rapidly buried, either during the biblical Flood or by some subsequent catastrophe over succeeding centuries.
Great age denied
It is astonishing that ‘readable’ DNA would survive burial in (originally wet) clay after hundreds of years, but not entirely impossible if the subsequent hardening was rapid, the water perhaps kept sterile by happenstance chemical contents and the subsequent sealing off from the environment was hermetically perfect. Low oxygen concentration and low temperature would also help.
However, it seriously strains credulity, to put it mildly, to believe that such a complex, fragile chemical, with its relentless thermodynamic tendency to break down in the course of time without any outside interference, would last for 17 million years! This is so whether this fossil formed slowly or rapidly.
Since the alternative is to challenge the entire sacrosant edifice of the age-dating system that has been set up so laboriously, it is certain that this undoubted fact of ‘fossilized’ DNA will be henceforth presented as if its 17-million-year ‘age’ is also factual. The reality is, however, that the find itself speaks against great age. Other leaves found in this rock when cleaved open are still coloured green (though they rapidly darken and curl up thereafter).2
The fossil magnolia species from which the leaf came had previously been classified on the grounds of its appearance as a closely related, but distinct species compared to living magnolias. Comparing the DNA sequences confirmed this.
- Edward M. Golenberg, et al., ‘Chloroplast DNA sequence from a Miocene Magnolia species’, Nature, Vol. 344, pp. 656–658, 12 April 1990.
- Karl J. Niklas, ‘Turning over an old leaf’, Nature, Vol. 344, p. 587, 12 April 1990.