Orks are thus genetically engineered to be muscular, aggressive, and none too bright; their technology is maintained by a caste of Oddboyz who possess genetically-implanted dispositions and technical knowledge that grant them unusual skill with maintaining and developing technology.
However, this skill is an unconscious one preserved through genetic memories hard-wired into the Oddboyz's DNA by the Brain Boyz millions of standard years ago.
Indeed, the Brain Boyz were apparently able to encode information on how to build simple machinery into the genomes of all Orks; thus Mekboyz require very little training in their function within Ork "kultur," since they understand mechanical principles at a fully instinctive level.