Feature Article - September 2007
by Do-While Jones

Ultraconserved DNA

Evolutionary bias drives terminology, and terminology drives thinking.

You may have heard the term, “ultraconserved DNA.”

Ultraconserved DNA was first described in May 2004, when a group led by David Haussler at the University of California, Santa Cruz, reported the existence of 481 stretches of DNA more than 200 base pairs long with completely identical sequences in mice, rats and humans. 1

The paper in question focuses on segments of 'ultraconserved' DNA — sections that have stayed exactly the same throughout recent vertebrate evolution, and are identical in humans, rats and mice (see page 10). The available evidence suggests that this extreme example of DNA conservation is no accident: the sequence stays because there is a strong selective force weeding out mutations in it. In other words, it is likely to be important to its host. 2

The basic assumption behind the term is that some parts of a creature’s DNA have not changed much over millions of years of evolution. That is, its DNA sequence has been “conserved.” If it hasn’t changed at all, then it is “ultraconserved.”

This terminology is based on the assumption that all DNA sequences are the result of random mutations filtered by natural selection, rather than design. Since the ultraconserved DNA segments are presumed to be the same because they have not changed during millions of years of evolution in different creatures, the existence of ultraconserved regions cannot be used to prove that these regions have not changed for millions of years. That would be circular logic.

An Amusing Waste of Time

Certainly there is value in examining DNA sequences, and attempting to correlate DNA sequences to functional results. Comparing DNA from various creatures is useful because it advances science in theoretical ways (basic understanding of life) and practical ways (medical breakthroughs).

Unfortunately, evolutionary scientists tend to get distracted in a futile attempt to reconstruct evolutionary history. DNA analysis can never establish the way in which creatures evolved if they are not really the result of evolution. It is an analysis that is doomed to fail, which wastes time, talent, and resources. It only results in some amusing conclusions. Here is one:

Only a single ultraconserved element has so far revealed its origins. By scanning genome data, Haussler's group found that one human ultraconserved element is 80% similar to a piece of DNA found in a 400-million-year-old class of ancient fish that includes the coelacanth. The element had been shuttled into the fish genome by a genetic invader called a retroposon, but mammals have now co-opted it to boost expression of a brain-development gene called ISL1. 3

Unbelievable! They found one segment of fish DNA that is 80% similar to human DNA, and jumped to the conclusion that humans got it by a “genetic invader” and co-opted it to do something other than what it does in a fish. This is simply fanciful speculation, but it somehow got through the peer review process and was reported as scientific fact in a prestigious scientific journal.

Facts Foul Up the Theory

Unfortunately for evolutionists, ultraconserved DNA presents a difficult problem for evolutionists. Remember, these regions are supposedly conserved because they are critical to the life of the organism. Scientists intentionally damaged some of these ultraconserved regions in some mice, expecting them to die. The cause of death would show what function these ultraconserved regions performed. When they did the experiment, they got surprising results.

A colony of mice whose very existence defies logic could rewrite our understanding of human evolution, health and disease, researchers say.

[Nadav] Ahituv [a human geneticist at the University of California, San Francisco] made four mouse 'knock-outs', each one lacking a stretch of DNA between 222 and 731 base pairs long. These same stretches of DNA exist in human genomes, base pair for base pair. This 'ultraconserved' DNA is exactly the same across the long evolutionary distance between humans and mice and rats. So why the mice lived could answer fundamental questions about evolution. 4

If it is really true that these segments of DNA have remained absolutely unchanged over millions of years of evolution because any change would make the creature unfit for survival, then changing them should kill the creature. But experiments have shown that mice can live without them. Apparently, there must be some sort of redundancy in the DNA code that allows the creature to function despite damage to these “critical” regions. It is almost as if the DNA code was designed to be robust enough to withstand some damage. But if that were the case, and if mutations in DNA have been going on for millions of years at the rate evolutionists believe, then these apparently redundant regions would have showed some mutations by now.

Our Rat Relatives

Finally, we cannot help commenting on “the long evolutionary distance between humans and mice and rats.” Evolutionary distance is said to be long or short, depending upon what suits evolutionists the best. The reason has to do with Animal Rights and Evolution, which just happens to be the topic of this month’s Evolution in the News.

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Footnotes:

1 Erika Check, Nature, 6 September 2007, “Crashing DNA's ultraconservative party” pages 10-11.
2 Nature, 6 September 2007, “Life as we know it”, p 1.
3 Erika Check, Nature, 6 September 2007, “Crashing DNA's ultraconservative party” pages 10-11.
4 ibid.