Several years ago a breeding loan was arranged between a couple of Vivid River Road females and a wild male River Road from the "Big Hill" on FM170. The resulting offspring exhibited aggressively busy and varied patterns, but fell mostly within the normal range of variation for the locality. Eventually, after various pairings of these offspring over the years, the Chaos trait revealed itself. The genetic component from the wild Big Hill male, the component that drives variability, appears to be prepotent. The baseline range of variation in the natural population of River Road alterna is notoriously high and teasing out what was going on with this group was difficult, especially in the very early days of the project. Creating a playbook that captures the Mendelian gene behavior that controls specific color and pattern elements is going to take a bit (a lot) more work, hopefully with other, brighter minds applying their efforts to the puzzle. For the time being I am only comfortable stating that the Chaos gene(s) is inheritable - details to be worked out.
The Chaos Factor
So what does a Chaos River Road alterna look like? It's not an easy question to answer because the Chaos animals seen thus far have had few diagnostic pattern or color indicators. They are visually recognizable by having pattern/color elements that are extraordinary, often in disarray, over-the-top, beautiful and fundamentally . . . chaotic. Some of the pattern and color types we have seen in the Chaos Rivers include:
* severely asymmetrical patterns
* unusual pattern symmetry (though seemingly at odds with the previous trait - the reality is that there doesn't seem to be much
middle ground with regard to Chaos pattern symmetry)
* smeared orange (not confined to saddles)
* grid type speckling layout
* more or less solid gray/charcoal/black - merged speckling
* orange striping - one to ten scales wide
* severely shotgunned orange saddles
* deep, tomato red "orange" on complete orange bands
* high reaching, black and white, lateral, vertically oriented tiger striping (sidewalls)
* very symmetrical, orange diamonds - mixed with speckling
* solid black "head caps" (rostral to parietals ) of the type usually seen in the eastern alterna populations, i.e., Devil's River
An additional diagnostic feature that seems to turn up in about 50% of Chaos specimens is an irregularly shaped "birthmark" - patches of dark, lithium gray that can reside anywhere on the body but appear most commonly on the anterior 1/3. The birthmark, when present, can be as small as just a few scales or it can cover most of the dorsal surface. The lithium birthmark is easy to see on light phase specimens, more difficult to discern on darker specimens and impossible to discern on the mostly charcoal/black specimens.
Another interesting feature that may prove out as a bonafide trait is the extra length of many Chaos animals. We have not attempted to qualify this phenomena but many of the juveniles do seem to grow extra long and wiry, gaining mass as they approach maturity but still remaining relatively long as adults. If real, this could be a welcomed trait, possibly indicating a better assimilation of the far from natural captive diet of lab mice. From an evolutionary perspective, this type of mutation seems ideally suited for sparking a "punctuated equilibrium" event, given the right set of environmental conditions.