Second, half-breeds exist. Magic-users can have children from giants, goblins, veela and, possibly, some other creatures. These half-breed can use magic, and there are two possibilities: they have MM genes or they have some m gene. m gene should be recessive gene, when appears with M gene, because according to HP wiki all known half-breeds can use magic. So half-breeds have MM or Mm genes.
Canon has Hagrid and Maxime (half-giant), Fleur and Gabrielle (one-quarter veela), and Filius Flitwick (part goblin). Veelas and goblins use forms of magic, but giants don't. That may be not because giants lack the genetic ability, but because they lack the attention or intelligence to learn how to make use of it, though. Goblins appear to have intelligence around human level, but use magic differently from witches and wizards.
Other species noted for using their own flavors of magic include house-elves and centaurs. There aren't any part-house-elf or part-centaur characters in canon or HPMoR, though.
I agree about giants, they may lack of training to use wizard's spells, but some of their abilities may be magic-based, for example, spell resistance, extra strength (comparing with non-magical creatures of the same size), maybe some regeneration ability.
Harry can make some broad study of non-human blood and find something interesting.
The next discussion thread is here.
This is a new thread to discuss Eliezer Yudkowsky’s Harry Potter and the Methods of Rationality and anything related to it. This thread is intended for discussing chapter 85. The previous thread has long passed 500 comments. Comment in the 15th thread until you read chapter 85.
There is now a site dedicated to the story at hpmor.com, which is now the place to go to find the authors notes and all sorts of other goodies. AdeleneDawner has kept an archive of Author’s Notes. (This goes up to the notes for chapter 76, and is now not updating. The authors notes from chapter 77 onwards are on hpmor.com.)
The first 5 discussion threads are on the main page under the harry_potter tag. Threads 6 and on (including this one) are in the discussion section using its separate tag system. Also: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15.
As a reminder, it’s often useful to start your comment by indicating which chapter you are commenting on.
Spoiler Warning: this thread is full of spoilers. With few exceptions, spoilers for MOR and canon are fair game to post, without warning or rot13. More specifically: