Part Two: Common Phenotypes of the FOXI3 Hh combination.
I find the old books with pictures of the Xolo or alternatively, the Chinese Crested in which they look alike, to be fascinating. They lead me to speculate about their interconnections. They also had a wide range of hairiness on the Hh gene that is now ignored by all of the hairless AKC breed standards, which aspire to the ideal type. Nowadays you don’t see pictures of the Hh dogs in all their variations. If you see them at all, they are trimmed to resemble the Breed Club Standard’s ideal. When bred, these dogs too, express all kinds of Hh phenotypes including the ideal balance of pattern-baldness with enhanced hair, compared to the Xolo Phenotype, which just has wisps.
Cursory research into Chinese Cresteds has indicated that that there are at least 4 common coat phenotypes in those with the Hh gene. They start with the ones covered all over with a single coat. The second general phenotype is a pattern of baldness in some variation of an “H” pattern of hair on the otherwise naked body. This phenotype is the least favored one for looks. The third phenotype is the favored pattern of baldness in the Chinese Crested, a hairless body with a nice crest and sox and plumed tail tip. The fourth phenotype is the xolo baldness pattern- naked except for sparse hair on the head feet and tail tip.
There still appears to be a mystery about the range of expression of the Hh gene. there is a continuum from completely covered Hairy Hairless (HHL) to skimpy patches on the head, feet tail as preferred in the Xolo. The common phenotypes could be a series of alleles or another factor on the H part. Each Hh pup gets these factors/alleles, which together, choose the degree and pattern of hairlessness. A very easy to understand article on how alleles work here: http://www.hobart.k12.in.us/jkousen/Biology/multalle.htm
In the absence of formal knowledge on the increasing pattern baldness from scientists, I want to poke around with different ideas. If I am wrong about something, I guess I’ll find out sooner or later and add to my knowledge.