Going of an old ask I read. If you have a group of cats that have been separated from the main group and have had little to no interaction (matings) from outsiders could they end up randomly getting some unusual genes to better match where they lived. Eh extra toes or water resistant fur or webbed toes on some that swim a lot. Like we see in spices that diverse or would that take hundreds of years to happen and not be something so fast? (Or end up with 90% of them having extra toes if in genes
Alright time to get to this ask from approximately forever ago. Thanks for being so patient! I knew it was gonna have to be a whole essay so it took me a bit to think about it.
The main thing to remember here, is that they are not going to randomly get genes (alleles, more technically) “to better match where they live”. That wouldn’t be random at all! The environment will affect how prevalent new mutations become, though.
For example, let’s say a cat got a new albinism mutation that is dominant, rather than recessive (this is very unlikely but we can talk about loss/gain of function another time). This cat is going to have a bit of a rough time due to light sensitivity and poor eyesight, but they still may survive, especially in a supportive environment like a clan. If they manage to pass on the gene, their offspring with albinism will have a significant disadvantage to surviving in the wild, so it is unlikely to become prevalent.
On the other hand, if a single cat ends up with webbed toes, that’s a pretty useful mutation if the cats are swimming, and some dogs and even humans have webbed toes, so it’s not too out there as a mutation. But this could become prevalent simply due to random chance as well - my dog is a lab mix with webbed toes, but he isn’t much of a swimmer. But they aren’t hurting him in any way, and they’re actually pretty difficult to notice since you have to physically stick your fingers between his toes (he is a good pup who doesn’t mind). So a desert clan could just as easily end up with lots of cats having webbed toes, just because that first webbed toes cat happened to be really hot.
In a population as small as a clan, the frequency of alleles can change quickly, due to natural selection or random chance. So it’s the frequency of mutations that you have to worry about. Mutations are very rare, which is a good thing! We wouldn’t want our DNA changing at the drop of a hat. Mutations that will actually have a visible effect that isn’t immediate death are even rarer. The trick to making them plausible is to pick something that can plausibly be a point mutation - that means just one gene has to fuck up for it to happen.
Good examples of this are fur mutations, polydactyly, bobtails, stuff like that. Something like significant changes to bone structure, feathers, etc. take multiple steps of mutations to achieve and would take a very long time for them to happen to line up conveniently. However, you can and should ignore this if you just wanna make cool mutant cats - use an excuse of radiation or something, it’s fine. Feathercats in particular are fun and I highly recommend making them, realism be damned.