Disclaimer: I know pretty much nothing about genes, and am also running purely on Coca Cola and self-hatred as I write this, so idk how much of it actually makes sense. If I can be bothered, I'll probably do a bunch of research after I've had some sleep and edit/update this to make it more accurate, cause I'm a massive nerd and put wayyyy too much effort into these sorts of things

⚠️ Also!! Warning for a minor(?) Crimes of Grindelwald spoiler near the start of the third paragraph, in case any of y'all are still trying to avoid those for whatever reason ⚠️

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I honestly can't remember if this is canon or not, but ever since I first read the Harry Potter series, I've been under the impression that witches, wizards, and wixes (non-binary magic-wielding people) get their powers from a (dominant) magical gene. This is why one or two magical parents tend to produce a magical child rather than a Squib, and why the gene can still sometimes resurface in Muggle families generations down the line (since iirc, Muggleborns come from Muggle families where a Squib married in and had kids at some point).

As an extension of this, I personally think that it makes sense for 'unusual' inherited powers, such as Parseltongue and metamorphosis, to simply be mutations of the magical gene. This would explain why they're generally passed down through the family rather than appearing in random people, with some powers being more likely to mutate than others. Naturally, this also means that the longer a family has carried the magical gene, the more likely it is for them to develop one or more of these mutations, and the inbreeding that happens with extreme blood-purist families like the Blacks and the Lestranges would make said extremist families the most susceptible.

I Am Tired and I have no clue how to end this, so... yeet? Hope you liked my sleep-deprived ramblings? 🙃😂