Wednesday, May 20, 2009

Where Darwin Went Wrong

Richard Dawkins talks with Paul Davies at the Origins symposium on a range of relevant topics, including Darwin and the Oxford climate (“I don't get to wear my Hawaiian print shirt at Oxford”). During the talk, Darwin emphasizes the shortcomings in Darwin’s understanding of evolution, notably, his failure to properly understand Mendelian heredity.

In a recent journal article, Jonathan Howard analyzes why Darwin failed to discover Mendel's laws of inheritance. After all, Mendel solved the puzzle from his monastery garden. Why couldn't Darwin? Howard argues that Darwin’s failure resulted from his commitment to the study of qualitative characteristics – height, weight, etc. – which provide a poor starting point for correctly analyzing heredity because their expression is controlled by multiple allelic systems as well as environmental factors.

Consequently, when Darwin published his theory of pangenesis, he completely missed the mark. In The Variation of Animals and Plants Under Domestication (1968), Darwin attributes the expression of phenotypes to the accumulation of “pangenes” from all over the body in the germ cells of the parents, which are then blended together during conception. On Darwin’s view, this accumulation is a continuous process, which constantly updates rather than a discontinuous one – hence, his notorious acceptance of the Lamarkian belief in the inheritance of acquired traits.

While Howard’s argument is interesting and potentially plausible, he downplays the importance of Darwin’s research motivations, namely, his overwhelming interest in the natural selection. In fairness, Howard does make moves towards this conclusion. He notes that in The Origin Darwin does rely on principles of heredity for his argument, for example, the recovery of the wild type from two, seemingly distinct recessive mutants, however, he brackets the question of the principles of heredity since his interest lies solely in proposing “atavism” as evidence for evolution. Nevertheless, Howard quickly passes over these examples as support for his thesis.

Cf. Howard et al. “Why Didn't Darwin Discover Mendel's Laws?”Journal of Biology, 2009; 8 (2): 15

Ben Picozzi

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