3 ms·
Why not two traits? One that determines if (Earth || !Earth) (call it the "Magic" gene) and one that determines (Pegasus || Unicorn) but only if the other gene
by a_t48 8y ago
Why not two traits? One that determines if (Earth || !Earth) (call it the "Magic" gene) and one that determines (Pegasus || Unicorn) but only if the other gene is active.
- gwern 8y agoI don't really like some of the mechanisms like dominance because it implies something for which we have no canon evidence: biases in discordant offspring towards particular types. And requires some rather specific patterns: in that case, it would require Mr and Mrs Cake to both have exactly 1 Earth/!Earth allele pair (so they become Earth but have a !Earth which can be passed on) and then each has a different Pegasus or Unicorn allele, which then also separately get passed on so they have two kids with !Earth/Pegasus and !Earth/Unicorn pairs. And it seems like if that were how it worked, you would expect way more discordant families to show up. (While polytomous threshold model can accommodate any level of rarity or stochasticness quite easily and naturally.)