Irreducible Complexity
Other examples of irreducible complexity abound, including aspects of protein transport, blood clotting, closed circular DNA, electron transport, the bacterial flagellum, telomeres, photosynthesis, transcription regulation, and much more. Examples of irreducible complexity can be found on virtually every page of a biochemistry textbook. But if these things cannot be ex- plained by Darwinian evolution, how has the scientific community regarded these phenomena of the past forty years?
A good place to look for an answer to that question is in the Journal of Molecular Evolution. JME is a journal that was begun specifically to deal with the topic of how evolution occurs on the molecular level. It has high scientific standards, and is edited by prominent figures in the field. In a re- cent issue of JME there were published eleven articles; of these, all eleven were concerned simply with the analysis of protein or DNA sequences. None of the papers discussed detailed models for intermediates in the de- velopment of complex biomolecular structures. In the past ten years JME has published 886 papers. Of these, 95 discussed the chemical synthesis of molecules thought to be necessary for the origin of life, 44 proposed mathe- matical models to improve sequence analysis, 20 concerned the evolution- ary implications of current structures and 719 were analyses of protein or polynucleotide sequences. However, there weren’t any papers discussing detailed models for intermediates in the development of complex biomole- cular structures. This is not a peculiarity of JME. No papers are to be found that discuss detailed models for intermediates in the development of com- plex biomolecular structures in the Proceedings of the National Academy of Sci- ence, Nature, Science, the Journal of Molecular Biology or, to my knowledge, any journal whatsoever.
Sequence comparisons overwhelmingly dominate the literature of molec- ular evolution. But sequence comparisons simply can’t account for the
Figure 20.3 Transport of a protein from the ER to the lysosome. Step I: A specific enzyme (gray oval) places a marker on the protein (black sphere). This takes place within the ER, which is de- limited by a barrier membrane (cross-hatched bar with ends curving to the left). Step II: The marker is specifically recognized by a receptor protein and the clathrin vesicle (hexagonal shape) begins to form. Step III: The clathrin vesicle is completed and buds off from the ER mem- brane. Step IV: The clathrin vesicle crosses the cytoplasm and attaches through another specific marker to a receptor protein (dark gray box) on the lysosomal membrane and releases its cargo.
