Comment Reply to Comment on ‘‘Evolutionary Roots of Iodine and Thyroid Hormones in Cell–Cell

I thank Lars Björn for taking the time and effort to submit his comments on my paper, ‘‘Evolutionary roots of iodine and thyroid hormones in cell–cell singaling’ ’ (Integrative and Comparative Biololgy 2009 49:155–66). He found one error and offered a few criticisms. I welcome the opportunity to correct the error and clarify the contentious points. The error first. Indeed, montmorillonite is not a metal but a clay mineral (a nonmetal) with some metal-like catalytic properties. The essential point is that montmorillonite has been shown to be ‘‘an ef-ficient catalyst for the formation of RNA oligomers’’ (Ferris 2006:1781). This information was included to support my suggestion that iodine (I2), which is known to be a powerful catalyst, might have promot