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YEC Best Evidence 10: DNA in ancient bacteria

This post is more than 6 years old.

Posted at 10:00 on 15 January 2018

Posts in this series:

  1. Sediment on the ocean floor
  2. Bent rock layers
  3. Soft tissue in dinosaur fossils
  4. The faint young sun paradox
  5. The earth's magnetic field
  6. Helium in radioactive rocks
  7. Carbon-14 in fossils, coals and diamonds
  8. Short-lived comets
  9. Salt concentration in the oceans
  10. DNA in ancient bacteria

We now come to the last of Answers in Genesis's top ten claims of evidence for a young earth. This one concerns the discovery of some still viable bacteria in 250 million year old salt crystals — a finding reported in Nature in 2000 by Vreeland, Rosenzweig and Powers.

The brief overview by Georgia Purdom gives very little detail about this discovery. However, Answers in Genesis has a more detailed technical article by Ewert van der Heide that gives some details and attempts an analysis to prove that the bacteria can not be as old as Vreeland et al suppose. The salt deposits, known as the Salado formation, come from the Delaware Basin (which, confusingly, is in Texas, not Delaware). Within these deposits, there are inclusions containing pockets of salt water, and it was in this salt water that the bacteria were found.

Naturally, the age of these bacteria has been greeted with a lot of scepticism by the scientific community as well. Responses by Hazen & Roedder (2001), Graur and Pupko (2001), Willerslev and Hebsgaard (2005), and Nickle et al (2001) among others, insist that the bacteria must be significantly younger than the deposits themselves. Purdom, of course, dismisses their response as "rescuing devices":

Some scientists have dismissed the finding and believe the Lazarus bacteria are contamination from modern bacteria. But the scientists who discovered the bacteria defend the rigorous procedures used to avoid contamination. They claim the old age is valid if the bacteria had longer generation times, different mutation rates, and/or similar selection pressures compared to modern bacteria. Of course these “rescuing devices” are only conjectures to make the data fit their worldview.

Are the crystals the same age as the deposits?

It's true that Vreeland et al took great care to eliminate contamination. They sterilised the salt crystal in concentrated hydrochloric acid and concentrated sodium hydroxide, and they reported no bacteria while they were drilling into the crystal, but only when they got to the salt inclusion. So at first glance, this one looks pretty convincing.

But the responses from other scientists aren't claiming modern contamination. They are proposing that the crystals themselves formed at a later date than the rest of the formation. This could have happened, for example, during a glacial maximum during the past 100,000 years, if water had seeped into the formation, causing some of the salt crystals to dissolve and then re-crystallise. Hazen and Roedder (2001) argued that the clarity of the crystal itself indicated that something along those lines was likely the case, and also pointed out that fluid samples from the Delaware basin vary widely in composition — a fact pointing to a mixture of both ancient and modern waters. Furthermore, as Nickle et al (2001) pointed out, Vreeland et al did not provide any tests to eliminate the possibility that the salt crystals might have subsequently re-formed in this manner:

It is not hard to imagine that water seeped into this formation (e.g., during a recent glacial maximum within the last 100,000 years), resulting in the formation of new salt crystals in an otherwise old geological formation. In contrast to their elaborate controls for contamination, they did not present any data to verify the age of the crystal from which they extracted the bacteria. Hazen and Roedder (2001) have argued that the clarity of the crystal from which they extracted strain 2-9-3 is consistent with this crystal being of a more recent origin. Hazen and Roedder also pointed out that the fluids in the Delaware Basin (the geological region from which Vreeland et al. obtained their sample) are extremely heterogeneous with respect to the “absolute concentration as well as the ratios of halogen, alkali and alkaline-earth ions,” suggesting that this region contains a mixture of ancient and modern waters, though Powers et al. (2001) have countered that such heterogeneity does not necessarily imply that these fluids are from different ages.

The fact remains that Vreeland et al have not managed to convince the scientific community that the bacteria were indeed deposited along with the halite 250 million years ago. There are other quite plausible mechanisms by which they could have been deposited at a later date.

The "rescuing devices" fallacy

Throughout these ten claims, we've seen a constant drumbeat refrain of perfectly reasonable old-earth explanations being dismissed out of hand as "rescuing devices." This reflects the YEC belief that long ages are nothing more nor less than an attempt to fudge things to accommodate the "evolutionary worldview."

But as I've repeatedly made it clear, long ages do not come from an "evolutionary worldview"; they come from measuring things. Remember that in order to build a case that the earth is young, you need to provide robust evidence that hundreds of thousands of high precision and extensively cross-checked measurements are consistently in error by factors of up to a million.

It is simply not sufficient to dismiss any explanations of the data that you don't like as "rescuing devices" or "only conjectures." You must provide evidence that rigorously and systematically falsifies them. In every single case that we've seen, YEC attempts to falsify these so-called "rescuing devices" have been inadequate at best, in some cases nonexistent, and in others even outright dishonest.

Before YECs can claim a slam dunk with this claim of ancient bacteria, they need to provide solid evidence that the crystals had not recently dissolved and re-formed. They must also provide evidence that the mutation rates really could not account for their great age, if that is what it turns out to be. Nickle et al proposed a couple of tests that could be carried out as a starting point to investigate the matter further. For example, they suggested carrying out a controlled study of mutation rates in this particular strain of bacteria under identical conditions, or testing the samples for the presence of carbon-14.

They will also need to provide other studies to corroborate this one. A single, disputed study is nowhere near sufficient to overturn vast swathes of high-precision, extensively cross-checked data.

Reproducibility is important in science.

This is important. The history of science is littered with extraordinary claims that fell by the wayside because they could not be replicated. One particularly well-known example of spurious results was Fleischmann & Pons's 1988 claim of having discovered cold nuclear fusion. Other teams were unable to replicate the experiment, and it is now regarded as spurious. A more recent example was the 2011 claim of the OPERA experiment to have discovered faster-than-light neutrinos: this turned out to be a hard to track down experimental error.

This being the case, findings, especially extraordinary ones such as this one, need to be replicated by multiple teams before they can be accepted as evidence. For what it's worth, this is the same as the Biblical principle that "every matter must be established on the evidence of two or three witnesses." (Deuteronomy 17:6; Deuteronomy 19:15; Matthew 18:16; 2 Corinthians 13:1.) If we could cite a single disputed study as evidence for anything, we would also be opening the doors to stuff and nonsense like homeopathy, and our hospital emergency departments would look like this:

[youtube https://www.youtube.com/watch?v=HMGIbOGu8q0&w=640&h=360]

The fact remains that there is simply not enough data to establish that the bacteria concerned really were the same age as the deposits in which they were found. This claim is yet another example of YECs drawing extraordinarily wide-ranging conclusions from extraordinarily slender evidence. It simply doesn't work.

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