A quick post about the K locus in the game, now that it's exposed in the Pack Info wolf bio in the public beta for 1.0.8l. If you don't know what the K locus is, watch this devblog before reading the rest of this post.
Research by Yellowstone biologists (including one of our advisors, Dan Stahler) into wolf genetics revealed that wolves with KK alleles were greatly underrepresented in the Yellowstone wolf population, presumably because KK wolves are more vulnerable to disease. Biologists don't really know when KK mortality happens -- is it mostly in utero, or when the pups are young, or sometime later before adulthood? So in the game, we spread it out, with some KK pups dying in utero (leading to smaller litters), and some being born but quite vulnerable to sickness and thus most are likely to die.
However, there is some chance of KK pups surviving. In their survey of Yellowstone wolves between 1998 and 2009, biologists found this distribution:
kk: 54%
Kk: 41%
KK: 5%
The game reproduces this (somewhat roughly) with pups, but also with adult wolves. We use this distribution to set the odds of dispersal wolves being kk, Kk, or KK. Furthermore, if you create a wolf with a black coat, it will have the same odds: 90% chance of being Kk and 10% chance of being KK. So your wolf can (unknowingly until now) be KK.
There was a quirk in the Wolf Customization functionality: Each time you click the Modify Wolf button, these kK/KK odds were rerolled, even if you didn't change the coat or tint. We've now fixed that (in 1.0.8l beta 41), so the odds are rerolled only if you change either of those things.