Self-Indulgent Zelda/Bio Combo Post

Searching around recently for an award-winning premise to a sensual-love-novel, I was guided towards the Gerudo, a band of all-female thieves from the game Legend of Zelda: Ocarina of Time. Legend states that they give birth to a male Gerudo only once every hundred years and it's strongly implied that they spend the rest of the time propagating themselves through breeding with Hylian men. While this does make for a fine premise, it doesn't make a lot of sense biologically.

For comparison:
A Hylian

A Gerudo

As you can see, Gerudo are distinguished from the Hylian race by the traits of red hair, rounded ears, large noses, and tanned skin. Which raises the question, if they're only able to reproduce with Hylians how has the Gerudo gene pool not been watered down to extinction by Hylian genes within a handful of generations?

On top of that, why are male Gerudo so rare? And how did this state of affairs come to be in the first place?

Not one to pen an erotic novel unless it's built on a foundation of hardcore science, I tried to create a couple of explanatory theories.

Theory one - the Gerudo females only mate with the Gerudo male
It's never explicitly stated that they mate with Hylians, only that they take them as boyfriends. Assuming they only bear offspring to the Gerudo male, the gene pool would be preserved, though the implications of such extensive and repeated inbreeding (they'd all be half-siblings) would likely be severe.

This theory also relies on the Gerudo being extremely long-lived, an idea that's not entirely unfounded. Ganondorf has been present in Zelda games often set hundreds of years apart, and Koume and Kotake are quoted as being 400 and 380 years-old respectively upon their deaths; the counter-argument to this being that all three of them channel some serious voodoo magic that may have life-extending properties.

However, even if we assume that the Gerudo are immortal, this is an extremely risky means of reproducing. If that one male Gerudo dies, through accident or injury, during the hundred year gap between male births - which is extremely probable considering the Gerudo's warlike nature and harsh, desert environment - then there'll be nobody around to conceive the next male, and obviously the result would be extinction.

This theory also fails to address the rarity of the male.

Theory two - the maternal chromosomes are static
This allows the Gerudo to reproduce with Hylians under the requirement that all the genes necessary to create Gerudo characteristics are present on the maternal chromosomes, which are passed on from the mother to the daughter unchanged and in their entirety. No crossing over occurs during meiosis and the chromosomes are non-randomly segregated, effectively making each generation a series of half-clones.

While feasibly able to continue indefinitely without loss of genetic material, the health repercussions would be considerable. A survivable level of genetic diversity would be maintained by the constantly changing paternal chromosomes, but the maternal ones would gradually accumulate deleterious mutations that they'd be unable to shake through the reshuffling that normally occurs during meiosis.

Again, the end result would likely be extinction.

Theory three - sex-linked Gerudo-ness
My personal favourite theory is that the genes that code for Gerudo traits are located entirely on a single sex-chromosome, unique from both the X and Y. This hypothetical chromosome, tentatively named the Z chromosome, would resemble the Y in being devoid of all vital genes, coding only for the traits of red hair, large noses, rounded ears, tanned skin, and perhaps a propensity towards violence and kleptomania, all of which would be controlled by a hormone also encoded on the Z chromosome, tentatively named gerudosterone.

This would sortof make them more of a sub-species or third sex rather than a race.

Because very little crossing-over occurs between sex-chromosomes, the Gerudo genotype is secure no matter how extensively they outbreed with Hylians, and the Gerudo phenotype is fine so long as the Gerudo alleles for hair colour, nose size, rounded ears, and skin colouration are dominant over all of their Hylian counterparts.

Under this theory, the reason that Gerudo males are so rare is because they're completely non-viable. A male Gerudo zygote with karyotype 46,YZ would lack the genes on the X chromosome necessary for cell survival. The only way that a male could be viable is if he had aneuploidy, an extra chromosome. Through a fluke of meiosis, one of the gametes could be sporting both sex-chromosomes, resulting in a zygote with a karyotype 47,XYZ. The rarity of the male Gerudo is simply a result of the statistic unlikelihood of this disorder occurring.

The combined effects of testosterone and gerudosterone on the individual would potentially result in violent tendencies and a predisposition towards pure evil-

- though the psychological effects of being an infertile and hypogonadotrophic lone male in a fortress of women should not be overlooked as a cause of mental instability.

Origin
Considering the origin of sexual reproduction is still something of a mystery, it would be difficult for me to theorize what would cause a third sex to evolve into existence, so for the time being I'm going to cop-out and say that magic did it.

The origin story of Hyrule goes that it was created by three Goddesses - Din, Nayru, and Farore. Of the trio, Din most strongly resembles the Gerudo - being associated with themes of power, earth and fire (they live in a desert), and the colour red.

So I'm going to go ahead and say that the Gerudo are a genetic abnormality created by Din in the image of Din, based on that little evidence.

And also the fact that GERUDOS is an anagram of U R GODES.

Which even I'll accept is a stretch.

GODES doesn't even sound like Goddess.

And text speak barely existed in 1998.