Falca’s mouth. she has peggy canines, but otherwise good dentition.
She is a single-coated xolo-chihuahua and puff cross.
This post is going to be edited many times as I collect or link to photos of xolo mouths.
Xolo-mouth is due to the hairless gene that first showed up in Mexico about 3-4 thousand years ago. It is an incomplete dominant mutation I call Hh, not a recessive one, so it does not breed true. It is also unknown in the homozygous dominant form, HH which indicate that the pups with this double dose of this dominant mutation never develop to birth. At least no one has published it- if it has happened. the recessive in this case (hh) is the normal hairy coat. When you have a mixed dominant, then you will get statistically about 25% with the homozygous hh gene or, hairy pups. This can not be eliminated as one of the alleles HAS to be (h).
As I have read up on heterozygous dominant genes in general, It appears they do not always work the same way as the hairless gene, except that the double dominant dose is always lethal or seriously damaging to the pup who gets it.
In general, I know that the H gene affects development in the uterus. It works on the hair and teeth at a very early developmental stage and, more or less, keeps them from developing properly. This stage in the uterus only lasts a brief moment. Thus no Hh dog has perfectly normal dentition nor has the normal double coat, because the gene works in a time frame of development only. I also know that 60 plus years of trying to breed the hairy hairless guys out has not worked to do anything but reduce the gene pool. It only seems logical, extrapolating what I do know for sure, that the gene only affects the pups over a tiny stage of development, maybe a few hours at most, but is variable in that short range so that some pups are hairier and some are still naked as it kicks in. I have not found the exact correct words to say this yet, but I think it is a good enough possibility to be checked out.
I will photo Ruthie’s mouth, and just for fun, Ollie’s. Ollie has just about perfect dentition- straight incisors, perfect scissor bite, totally normal dentition, perfectly developed.