Then I realized:

Biology = Chemistry = Physics = Math

Keep in mind that if it hasn't appeared in a sanctioned publication it's not true. Also keep in mind that SR books are not meant to be medical texts, so in the interests of word count and approachability, they're not written like them.

There are two divergent theories associated with the DNA structures involved in metagenetics and magigenetics.

The first theory is that there is a third strand of the DNA helix which is entirely astral. That strand is what actually dictates metatype, magical ability, et al. In the presence of an adequate mana background count, this strand can be expressed. In its absence, it cannot. This theory obviously requires the presence of additional "proteins" and nuclear structures that exist only on the astral plane.

The second theory is that there are implicit features in an organism's aura that dictate the conformation of DNA tertiary structures allowing for expression of metagenes. In the presence of an adequate mana background count, these conformations are assumed. If the resultant tertiary structure allows for the expression of a gene, then it's expressed. In the absence of both the requisite mana background count and the resultant coding gene, they are not expressed.

It's possible that both of these theories are true, just that different metagenes are expressed through the two contrasting mechanisms. In the game world, there is ample evidence to support both of these. Of the identified metagenes, some were identified by techniques associated with each of these two theories.

BTW (and back on topic) I like the Detect [Metahuman] Spell as a diagnostic test. I would allow that for elves and dwarves for sure, particularly in later gestation and any trolls and orks that goblinize in utero.

I have always thought the astral chromosome or astral strand theory made the most sense. And if the astral component had the ability to materialize (like a spirt) during key points in embryonic development you would not need astral transcription machinery. The dual natured DNA could interact with the mundane cellular proteins.

Of coarse its wise for the writers not to endorse any one theory or explain everything. Being able to run a simple genetic screen for magical traits is verging dangerously close to the worst sci-fi idea ever created by man- midi-chlorians.

Just a quick reminder to everyone... Shadowrun is fiction, Magic isn't real, and Game Designers just make up whatever they think is "cool".

Just a quick reminder to everyone... Shadowrun is fiction, Magic isn't real, and Game Designers just make up whatever they think is "cool". Somehow, I suspect you're all overthinking this a little bit

Bull

As evidenced by this XKCD strip.

Yeah Freud was just an obsessive pervert who's idea probably would have been discarded if he hadn't lived in a the prudish climate of Victorian period. I think Carl Jung was a lot more badass.

It is impossible to fully separate the two due to their friendship and influence on each-other, particularly Freud's influence on Jung. I'm also afraid that Freud would defeat Jung in unarmed combat should such a battle ever occur.

Not if the fight took place between 1940 and 1961.

-Frank

Sorry, I just tend to like to understand stuff and have it make sense, even if it doesn't exist.

The first theory is that there is a third strand of the DNA helix which is entirely astral. That strand is what actually dictates metatype, magical ability, et al. In the presence of an adequate mana background count, this strand can be expressed. In its absence, it cannot. This theory obviously requires the presence of additional "proteins" and nuclear structures that exist only on the astral plane.