A fan asked me how Darrendrakar genetics work. Well, it’s more complicated than *I* can understand completely, but let me at least tell you a few things.
If you’ve read my young adult Unexpected Heroes fantasy series, set on the world of Kaiatan, you’ll know that the shapeshifters in the country of Darrendra have one alternate form that is as natural to them as their two-legger form. (You can’t call them human. “Human” is a Terran species, and “humans” can’t change shape, sorry. Darrendrakar do go by “man, woman, or person,” though.)
In book one, Wind of Choice, the shapeshifter we get to know the most is Ludik. His alternate form is a black jaguar. (Trivia: any of the big cats, when black, can be called panthers.) He comes from the kindred (tribe) of cats, called Felid. Furthermore, he comes from the sub-group of “big” cats, which includes lions, tigers, jaguars, leopards, and the makarodonts that include such lovely specimens as sabre-tooth tigers (although the Darrendrakar call them something else).
In Darrendra, any of the big cats are cross-fertile, as is evident from Ludik’s mother being a tiger and his father being a lion. This is different from Terra (our Earth), where you almost never get that sort of thing, except for mules. (But sometimes… http://ligerworld.com/shasta-the-first-ever-liger-in-America.html ) On the rare occasion you get a cross on Earth, the child is not fertile. In Darrendra, they are. In fact, you can get all sorts of results, depending on what genes run in the family. The Darrendrakar don’t have “mixed” children, like ligers. The genes will fall out on one side or the other, or select from other ancestral genes. Ludik has two brothers that are lions, a brother and sister that are tigers (one orange, one golden), and a sister that is a jaguar (but spotted instead of black).
Oddly, Ludik’s identical-as-two-legger brother is a lion (not a jaguar) when he changes shape. Why they look so similar as people and so different as cats is one of the mysteries of Darrendran biology that I can’t explain. And if you ask a Darrendrakar, he’ll just shrug and ask why not.
What you DON’T get in Darrendra is the big cats crossing with the small cats (not housecats, but cheetahs, mountain lions, ocelots, etc). Well, they could mate, but they either wouldn’t have children (most likely), or their children would be sterile. (Within the small cats, they are cross-fertile between types, just as the big cats are within their own group.)
The same difficulty works across Darrendrakar kindreds. Sure, a Felid and a Canid could marry, but they wouldn’t have children. Add in the typical uneasy peace between kindreds, and an interkindred marriage would be pretty difficult. Even without being “forbidden,” that kind of reality tends to discourage most interkindred romances.
This is also why you hardly ever see marriages between the four different peoples on Kaiatan. The winged Iojif, the shapechanging Darrendrakar, the gilled Nokai, and the solar-powered Iskri almost always marry someone from their own kind. And you never, never see an avian with gills or a solar-powered shapeshifter. The genes do not mix that way.
So, what did I leave out that you want to know? Leave a question in the comments, and I’ll do my best to answer it!