LRRTM1 & bicameral mind theory
It seems that there is more data that may be taken as evidence for Julian Jaynes's bicameral mind theory. The gene LRRTM1, which increases the odds of a person being left-handed, is also apparently linked to increased odds of schizophrenia -- exactly as would be predicted by Jaynes's theory.
see also:
http://news.nationalgeographic.com/news/2007/08/070801-left-gene.html
http://anthropology.net/2007/08/01/lrrtm1-a-possible-gene-for-left-handedness/
http://www.nature.com/mp/journal/vaop/ncurrent/abs/4002053a.html