Genes Attack the Trees
Evolutionary tree-building (11/14/2005) is a tangled business. Now that scientists can compare genomes of diverse animals, they can compare the resulting molecular evolutionary trees with traditional ones – those produced by inferring relationships based on outward (morphological) characteristics of living or fossil organisms. What happens when the trees don’t match?
Two recent studies, both reported by Science Daily, have demonstrated that molecular-based trees, to be believed, require uprooting long-standing morphologically-based evolutionary trees.
- Iguanas Promoted: A “radical reorganization” of the tree of reptiles was reported by Science Daily based on work by two Penn State biologists. Iguanas, for instance, had long been placed near the bottom of the tree due to their “primitive” appearance. Now, the molecular tree graduates them to the top. The new study compared 19 genomes from all the major reptile lineages. So many anomalies were found, the researchers had to invent entirely new categories of classification. In addition, most of the branches appeared to start early and remain relatively unchanged over vast periods of time. Toxic venom, for example, was thought to be a recent innovation, but now appears rooted at the time of the earliest dinosaurs. Reptiles with two egg teeth appear to precede those with one egg tooth – a step toward simplicity, not complexity. These and other findings are inverting a family tree of reptiles accepted by evolutionary biologists for over a century. One of the team members said, “If this new tree is correct, all the morphological characters that traditionally have been used to identify similarities between species will need to be reevaluated to understand how these traits evolved” (emphasis added in all quotes).
- Slow Humans: Another startling finding reported in Science Daily started with the title, “Early Animals Had Human-Like Genes.” If humans are the late-comers, why and how did early-Cambrian roundworms produce innovations that would persist unchanged for hundreds of millions of years? The team compared human and fruit-fly introns with those of a roundworm thought to be 600 million years old, close to the period of the very first multicellular organisms. Contrary to earlier expectations, introns – those spacers in the DNA cut out by the transcription machinery – were already present in the worms and have persisted all the way to the human line, while other branches, like insects, lost many of them quickly. To save the evolutionary tree, researchers are speaking of “fast-evolving” and “slow-evolving” branches. “The worm’s genes are very similar to human genes,” said one. “That’s a much different picture than we’ve seen from the quickly-evolving species that have been studied so far.” Another remarked, “Now we have direct evidence that genes were already quite complex in the first animals, and many invertebrates have reduced part of this complexity.” Not only were the introns the same, but their positions within the genome “have been preserved over the last half a billion years.”
Overall, the picture looks opposite what evolutionary biologists have expected: “this has shown us is that evolution is not always about gain; the loss of complexity can equally be an important player in evolution.”
What’s most amazing about both these stories is not the genes. It is the psychology of Darwinists. They can hang on to a theory no matter how much contrary evidence comes to light. Invented terms like “conserved genes” and “slow-evolving species” mask their desperation. They are clinging to a dogmatic evolutionary position in spite of evidence that looks like creation: abrupt appearance, stasis, and loss of original complexity. Simultaneously, they accuse creationists of accepting their view on “faith” while bluffing that “there is no controversy among scientists about evolution.” Yet how would an impartial jury rule, based on the empirical evidence alone, with no evolutionary presuppositions?