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Monkey Brains Evolution -- A Response to the Union Tribune

By Mario A. Lopez

[Editor's Note: The following response was written by IDEA Center staff member Mario Lopez to the article in the Union Tribune entitled, "DNA slice key in human-chimpanzee split discovered," by Eric Berger, published on August 24, 2006]: What selective advantage could there be for larger brains? Well, None. This “holy grail” discovery of the ASPM (abnormal spindle-like microcephaly) gene back in 2001 has had Darwinists raving about another possible link between chimps and humans. What we have really discovered is simply the gene responsible for microcephaly, a condition which causes a drastic reduction in the size of the brain’s cerebral cortex. The idea here is that the rapid growth of this region, which is responsible for abstract reasoning, planning and language, must have conferred some selective advantage to what would otherwise be nothing more than monkey brains. However, the question as to what advantage a larger brain would bestow is highly speculative.

Having gained a larger clump of brain (probably cramped into a small cranium); selection would require a natural ability to use it. In other words, the novel neural infrastructure would be useless unless it could serve for meatloaf for subsequent generations, or perhaps find itself doing “abstract thinking” ex nihilo. Moreover, the gene (asp) which affects cell division required for either larger brains or novel neurons demonstrates yet another example of irreducible complexity. That is, an exponential increase in brain size requires a mechanism to promote an increase of genomic information—not a degradation of it. Therefore, we have an idea of which sequence is required to get a larger brain, but not how genetic entropy produced it in the first place.

It is also important to recognize that the so called 98.5% of genetic similarity between humans and chips is as reliable a number as wild guessing today’s Lotto numbers. For example, Dr Soojin Yi of the Georgia Institute of Technology says the similarity is more like 96%, while Roy J. Britten at the California Institute of Technology said it was 95%, and researchers at the University of California, Berkeley thought it was around 99%. Don’t be surprised if these estimates change again, after all, what are a few genes here and there, right?