World Building: Mageborn and random rolling...

[hal]

As part of a project that I'm running elsewhere - I"m developing the tools necessary for myself to generate randomly generated mageborn. Fun thing is, what I have is already fully functional in the sense that I can generate all four attributes for the "Adult body" plus the magery level based upon the premise that Magery is bestowed in a 10:1 ratio.

Ie, Magery 0 people are 10x more common than Magery 1, and that Magery 1 people are 10x more common than Magery 2, and that Magery 2 is 10x more common than Magery 3.

But - I found too, that this kind of ratio based "planning" by the GM doesn't HAVE to follow the 10:1 ratio. If you wanted to get "Mystical" you could use the magic number 7 or even 3 for your assigned Ratios.

So, how does that work? If 2% of your entire population statistically have magery of any kind, then for every NPC in your population, there is a 2% chance they might be mageborn. If you want to say "those who have mageborn parents have 15x the chance of being mageborn while those who don't have magery blessed parents only have 1%" - that could be done as well. The point is, as GM, you could and should be able to generate information about those NPC mageborn at the single click of a button right?

But, here is the fun part.

What if you have it such that you know (because some yahoo created rules for the odds of twins being born to a given population) that a single person has magery, and that you hit the jackpot - you were born a twin.

Would you expect that the twin should also have magery? How might history unfold for those two children, one a mageborn, the other not?

So, what are your thoughts on the Mageborn with regards to twins?

Identical twins (both the same gender obviously)
Fraternal Twins (different genders)
Fraternal Twins (same gender)

Of course, the same that is said about twins can be said of triplets. Just asking for general thoughts here. :)

[Shuckster]

I feel like it comes down to weather or not magery is genetic in that setting, which given that magical parents make magery more likely, but not a sure thing implies recessive genes.

Using pundit squares and the assumption that the mage gene is recessive we get three types of people. Those who are not mages and cannot have mage children, Those who are not mages but might have mage children, and mages who might have mage children. Of these three types we get six possible couplings, and of those couplings there are four possible combinations of dna from each parent for that trait. Of these 24 possible children only 6 are mages and 9 are carriers, which is a 20% chance of magery and a 27.2727 chance of being a carrier of magery, but that assumes there is an equal number of all three types of people. Since we want only a 1-2% chance we will assume that the mage and mage-carrier populations are much, much smaller than the non-magical non-carriers.

On earth we have 7.8 Billion people, so using this ratio only 156 million people on our earth would be mages of any kind. With one hundred sixty-seven million three hundred forty-five thousand four hundred twelve of the remaining humans at least being carriers. This means that the remaining human population would be the non-magical non-carriers.

Non identical twins by definition do not have the same dna, so the odds of them being born magical are the same odds that their mage twin had with no increase.

According to a a study done in 2021 of 300 pairs of identical twins, only 38 had perfectly identical DNA, from this figure we can get a ratio of 38 identical pairs to 262 nearly identical ones, which is a 12.6667% chance of the twin having the exact same dna as the other twin. Still, having exactly the same dna isn't the actual requirement for the twin to also be magical, its just having the one gene in common.

With that in mind you need to take the parents in to account

The couplings which can result in mages include:
A mage and a carrier: 50% chance of magery
A mage and a mage: 100% chance of magery
anyone else: no mages possible.

The low population density could be caused by the fact that recessive traits naturally have lower numbers and the only way humans have forced the number of recessive traits in humans to increase has been through eugenics and inbreeding, both of which are harmful to the overall population in the long run, it could be that any attempts to create larger numbers of mages ended in failure or genetic defects, or have otherwise not been attempted for social reasons.

So basically of the 2% of the world thats mages, and in real life 3 or 4 in every 1,000 births are identical twins (according to wikipedia anyway). So of those 156 million mages, 4680-790 of them were born as identical twins. Of these only about 592-790 have a twin with the exact same dna as they have, and this is in a population of 7.8 billion. Unless we ignore the study.

if we ignore the recent study than:
Identical twins: both will be mages 100% of the time.
Semi-identical twins: both will be mages 75% of the time
fraternal twins: both will be mages 50% of the time, with that other 50% being when they are different sexes.

[StevenH]

As it is with all worldbuilding, it depends. If magery is genetic, then identical twins should either both be mages, or both nonmages. Fraternal twins only share half the genes, so it's a toss up. Same goes for triplets.

If an aspect of magery is caused by something outside of genetics (symbionts, god-given gift, being born close to the Well of Magic, initiation ritual, whatever) then again, it's a toss up.

I for one tend towards magery having a genetic component, for whatever reason (likening it to a science, maybe, or a desire to have a group of elites, I don't really know). Maybe I like the mix of predictable and unpredictable.

Although after reading some stuff on another thread, the manaparasite/symbiont is starting to grow on (in?) me. Especially since most of the magic I run is just part of the local physics, and if that is the case, then all of the lifeforms on the world would have a chance to access it in some way. And a mana-using life form that invades other life forms and shares its power as a way to get along with its host is a cool one.