Board Thread:General Grimm Discussion/@comment-26184732-20150309031541/@comment-69.91.87.55-20150309175257

The only beasts (Wesen) that I know of that look like deteriorted corpses are the Hexenbiests, right? I'll assume that for the time being.

Most Wesen are genetic chimeras - single organisms composed of genetically distinct cells (Season 1, Big Feet). Under normal circumstances, their animal nature is supressed and they appear as normal humans. When they become emotionally agitated, stress related hormones stimulate the expression of their animal characteristcs (the Woge.)  I suspect that in the early stages of Woge, the mechanisms that normally suppress these characteristics still predominate, and this sets up a  rapid oscillation between the two states which is subliminal to most humans. Grimms are able to percieive this early stage of Woge because they have more than 3 types of cone cells in the macula of their eyes. (Season 4, The Last Fight) Cone cells not only allow for color vision, they are also allow for the perception of finer detail and rapidly changing images. Normal humans are only able to percieve Wesen after the onset of the full Woge, which I surmise is a kind of phase transition in which the Wesen's normally suppressed animal nature becomes dominant over their human form.

As an aside, I imagine that Wesen also have this increased visual acuity, which is what allows them to percieve each other during the early stages of Woge. There is evidence that most mammals in the past possessed 4 types of cones but lost one or two due to a genetic change. So I suspect Wesen retain this enhanced visual ability along with their secondary animal characteristics, normal humans have completely lost this ability, and Grimms are sort of a "missing link," retaining the ability to precieve Wesen during the early stages of Woge but lacking a specific secondary animal nature themselves.

We don't really know but, I suspect that Hexenbiests are something slightly different. I've discussed this in detail elsewhere but, in a nutshell, my theory is that the Hexenbiest "phenotype" is the result of  elevated X chromosome activation. In normal female mammals, one X chromosome in each cell is suppressed early in development in a process known as X inactivation (or sometimes Lyonisation, after its discoverer.)  In Hexenbiests, both X chromosomes are active (in a least some cells) leading to enhanced neural activity (a large proportion of the genes located on the X chromosome code for brain function) which gives rise to their telekentic abilities. The appearance of decaying flesh is a secondary side effect arising from the overexpression of other, non-brain function related, X linked genes.

Just to be clear, unless a statement above is followed by a reference to a specific Grimm episode, this is all just idle speculation on my part. I really have no idea what the writers have in mind, other than that the existence of these beasts is somehow genetic in order. For anyone interested, most of the info on cone cells, etc, can be found on Wikipedia. I also recommend (hope this is alright) The Epigenetics Revolution by Nessa Carey for a very readable account of the latest discoveries concerning gene expression and inheritance.

Cheers!