Board Thread:Theories and Speculation/@comment-1512913-20161119171442/@comment-1512913-20161208153100

Same filler which states that Kekkei Tota users have affinity for 3 natures, also states that Kekkei Genkai users have affinity for 2 natures. In other words, you just can't find anyone and who has affinities for Fire, Earth, Wind and tech them Dust, because having more than 1 affinity is genetic, Kekkei Genkai.

With what Gaara Hiden says, then Kekkei Tota is indeed combination of several Kekkei Genkai.

So no @Actionman, it's certainly genetic. 3rd Kazekage was said to have taught the 4th Magnet Release as well, but that's only because 4th had necessary genetics which allowed him to learn it.