Old DNA, Bacteria, Proteins, and Soft Tissue? 1
DNA. When an animal or plant dies, its DNA begins decomposing (a). Before 1990, almost no one believed that DNA could last 10,000 years (b). This limit was based on measuring DNA disintegration rates in well-preserved specimens of known age such as Egyptian mummies. DNA has now been reported in supposedly 17-million-year-old magnolia leaves (c) and 11–425-million-year-old salt crystals (d). Dozens of plants and animals have left their DNA in sediments claimed to be 30,000–400,000 years old (e). DNA fragments have been found in the scales of a “200-million-year-old” fossilized fish (f) and possibly in a “80-million-year-old” dinosaur bones buried in a coal bed (g). DNA is frequently reported in insects and plants encased in amber, both assumed to be 25–120 million years old (h).
These discoveries have forced evolutionists to reexamine the 10,000-year limit (i). They now claim that DNA can be preserved longer if conditions are dryer, colder, and freer of oxygen, bacteria, and background radiation. However, measured disintegration rates of DNA, under these more ideal conditions, do not support this claim (j).
a. This natural process is driven by the continual thermal vibrations of atoms in DNA. Just as marbles in a vibrating container always try to find lower positions, vibrating atoms tend to reorganize into arrangements with lower energies. Thus, DNA tends to form less energetic compounds such as water and carbon dioxide.
b. Bryan Sykes, “The Past Comes Alive,”
Nature, Vol. 352, 1 August 1991, pp. 381–382.
“Many scientists still consider this idea [that DNA could last longer than 10,000 years]
far fetched, but Poinar points out that not long ago few people believed any ancient DNA could be sequenced. ‘When we started, we were told that we were crazy,’ he says.” Kathryn Hoppe, “Brushing the Dust off Ancient DNA,”
Science News, Vol. 142, 24 October 1992, p. 281.
c. Edward M. Golenberg et al., “Chloroplast DNA Sequence from a Miocene Magnolia Species,”
Nature, Vol. 344, 12 April 1990, pp. 656–658.
DNA disintegrates faster when it is in contact with water. In commenting on the remarkably old DNA in a supposedly 17-million-year-old magnolia leaf, Svante Pääbo remarked,
“The clay [in which the leaf was found]
was wet, however, and one wonders how DNA could have survived the damaging influence of water for so long.” Also see Svante Pääbo, “Ancient DNA,”
Scientific American, Vol. 269, November 1993, p. 92. [Maybe those magnolia leaves are not 17 million years old.]
“That DNA could survive for such a staggering length of time was totally unexpected—almost unbelievable.” Jeremy Cherfas, “Ancient DNA: Still Busy after Death,”
Science, Vol. 253, 20 September 1991, p. 1354.
d.
“Fragments of 16S ribosomal RNA genes were detected by polymerase chain reaction amplification of DNA extracted from halite [salt, NaCl]
samples ranging in age from 11 to 425 Myr (millions of years).” Steven A. Fish et al., “Recovery of 16S Ribosomal RNA Gene Fragments from Ancient Halite,”
Nature, Vol. 417, 23 May 2002, p. 432.
e. Eske Willerslev et al., “Diverse Plant and Animal
Genetic Records from Holocene and Pleistocene Sediments,”
Science, Vol. 300, 2 May 2003, pp. 791–795.
f. Hoppe, p. 281.
Virginia Morell, “30-Million-Year-Old DNA Boosts an Emerging Field,”
Science, Vol. 257, 25 September 1992, p. 1862.
g.
“Under physiological conditions, it would be extremely rare to find preserved DNA that was tens of thousands of years old.” Scott R. Woodward et al., “DNA Sequence from Cretaceous Period Bone Fragments,”
Science, Vol. 266, 18 November 1994, p. 1229.
Some have charged that the DNA Woodward recovered from a large Cretaceous bone in Utah was contaminated with human, or perhaps mammal, DNA. Several of their arguments are based on evolutionary presuppositions. Woodward rebuts those claims in “Detecting Dinosaur DNA,”
Science, Vol. 268, 26 May 1995, pp. 1191–1194.
h. Hendrick N. Poinar et al., “DNA from an Extinct Plant,”
Nature, Vol. 363, 24 June 1993, p. 677.
Rob DeSalle et al., “DNA Sequences from a Fossil Termite in Oligo-Miocene Amber and Their Phylogenetic Implications,”
Science, Vol. 257, 25 September 1992, pp. 1933–1936.
Raúl J. Cano et al., “Amplification and Sequencing of DNA from a 120–135-Million-Year-Old Weevil,”
Nature, Vol. 363, 10 June 1993, pp. 536–538.
i. Tomas Lindahl is a recognized expert on DNA and its rapid disintegration. He tried to solve this problem of “old” DNA by claiming that all such discoveries resulted from contamination and poor measurement techniques. He wrote,
“The apparent observation that fully hydrated plant DNA might be retained in high-molecular mass form for 20 million years is incompatible with the known properties of the chemical structure of DNA.” [See Tomas Lindahl, “Instability and Decay of the Primary Structure of DNA,”
Nature, Vol. 362, 22 April 1993, p. 714.] His claims of contamination are effectively rebutted in many of the papers listed above and by:
George O. Poinar Jr., in “Recovery of Antediluvian DNA,”
Nature, Vol. 365, 21 October 1993, p. 700. (The work of George Poinar and others was a major inspiration for the book and film,
Jurassic Park. )
Edward M. Golenberg, “Antediluvian DNA Research,”
Nature, Vol. 367, 24 February 1994, p. 692.
The measurement procedures of Poinar and others were far better controlled than Lindahl realized. That is, modern DNA did not contaminate the fossil. However, Lindahl is probably correct in saying that DNA cannot last much longer than 10,000 years. All points of view are consistent when one concludes that these old ages are wrong.
j. “We know from chemical experiments that it [DNA] degrades and how fast it degrades. After 25 million years, there shouldn’t be any DNA left at all.” Rebecca L. Cann, as quoted by Morell, p. 1862.
[From “In the Beginning” by Walt Brown]