Wednesday, July 20, 2016

Kai'us Racial Genetics

This is the last of series of posts regarding Kai'us culture (for now).
The first bit was a five-part series last month going into the Kai'us creation myths.
Earlier this month I also talked about the system Kai'us' use to prevent inbreeding.

This post will talk about how interracial Kai'us pairings work on an over-simplistic genetic level.
Kai'us races are different from Human races.  What we consider different "races" are just regional and ethnic variations.  Any human can successfully produce viable offspring with any other human.  In short: every "race" of humanity can interbreed.

When I refer to "race" in regards to Kai'us', I'm actually referring to different sub-species.  The seven genetically-unique Kai'us races can successfully interbreed and produce fertile offspring, but the racial genetic markers do not hybridize and it's possible (easy actually) to "breed out" specific genetic markers.

This hasn't always been the case however.  When their world goes through its periods of great geological instability, everyone's DNA becomes unstable and hybridization occurs much more freely.  During the time period I'm working in though (Post-Second Cataclysm onward), Kai'us DNA is incredibly stable to the point where chromosomal abnormalities are practically unheard of.  Even identical twins are incredibly rare (though fraternal twins are actually more common than among humans).

Before I go into the details though, let's refresh ourselves on basic genetics.  Remember that every person typically has two genes for any particular trait: one gene they get from their mother and the other they get from their father.  Using that Punnett Square I mentioned in the last post, let's do an easy one and lay out the probability of parents producing a boy or a girl child.  (Genetic) gender in humans is determined by the x- and y-chromosomes.  If you have two x-chromosomes, you're genetically female.  An x- and a y- together makes you genetically male.

Let's step it up a notch and pretend a person's height is determined by one of only two genes: "T" would produce tall people, "s" would produce short people, and a combination of the two would produce a person of medium height.

Okay, so now that you've recovered from flashbacks of Biology class, let's apply these principles to Kai'us'.  As mentioned before, I'm going to over-simplify the following explanation significantly since no one gene determines all of a Kai'us' racial characteristics, but to make both our lives easier, let's just say that Kai'us race is determined by either a dominant (D) or a recessive (r) gene.

Pairings made from the same race can produce viable offspring no matter what combination of genes are expressed (DD, rr, or Dr would all be viable combinations).

When you start blending races however things get tricky: to produce viable (live) offspring, one parent must provide a dominate racial gene, and the other parent must contribute a recessive racial gene.  Two dominate genes or two recessives will not produce live young.  Interestingly enough, when interracial pairings do occur, people are often more drawn to each other when they're genetically compatible.

Another nice thing is that any children produced with the requisite dominate and recessive genes will be fully fertile and able to produce offspring of their own.

For our first hypothetical pairing, let's put together a Spider Kai'us (represented by a "$" for dominate, and an "s" for recessive), and a Cave Kai'us (C for dominate, and ¢ for recessive) as this would be the most probable pairing, especially among the Ka-Kiu.

Spider Kai'us' are a tall, desert-dwelling race with four arms.  Red/orange mane colors are not uncommon among them, but various shades of brown are the norm (running more to the lighter end of the spectrum).  Brown eyes are by far the most common, but other shades pop up here and there and run strongly in families when they do appear.

Cave Kai'us' bear the "basic" Kai'us form (two arms, two legs, and average build).  For mane colors, nearly every shade of brown can be found among them, though the extremes (blond at one end and black at the other) are very rare.  Like most races, brown eyes are what you're most likely to find, but Cave Kai'us' are the most likely to have dark blue or dark green eyes of any other race.

Obviously this isn't the only combination that will produce viable offspring.  A $s Spider Kai'us parent could have children with a ¢¢ Cave Kai'us (with a 50% success rate; all children would have four arms), or even a CC Cave Kai'us (50% as well; with two-armed children).

A $$ parent could have children with a C¢ person (with 50% success; all children would have four arms), as well as a ¢¢ person (100% success; all children would have four arms as well).

A ss parent could also have children with a C¢ person (also with a 50% chance of success; all children would have two arms though).  Mating with a CC person would provide a 100% chance of Cave Kai'us hybrids.

Even though statistically there's a 50/50 chance of a genetic mismatch with most combinations; nearly every attempt at conception will produce a viable baby.  This is because Kai'us' tend to only mate six times in their entire life. (The reasons are many) and Nature will do everything in its power to ensure the right genes match up to produce live offspring.

Now let's pair up a few hybrids and see the interesting combination that get produced:

For chuckles and giggles, let's introduce a third race.  Though this is rare, even among the Ka-Kiu, let's put together a Cave and a Spider hybrid that both carry the racially recessive genes for Mountain Kai'us' (represented with an "m").

The Mountain People have a heavier build than the other races. They're known for their physical strength; and they have thick, bristly hair that runs down the backs of their arms and legs the same color as their mane.  Both their mane and eyes colors are consistently darker than the other races, almost always dark brown or black. 

From this combination, you can see there's a 25% chance of no viable offspring, a 25% chance of a Cave/Mountain hybrid, a 25% of a Spider/Mountain hybrid, but a 25% of a genetically pure Mountain Kai'us.

And so there's the long and the short of Kai'us racial genetics.
I hope you've enjoyed this peek into the science end of Kai'us'.
If you liked what you've read these past two months, be sure to bug me periodically to get the book finished so you can read a whole novel about these fascinating creatures!

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