is there a specific gene that makes dilute calicos?
dilute calicos are just recessive colors, meaning their parents were either recessive (gray, cream, fawn, lilac etc) or they both carried the recessive gene instead of having complete dominance.
BB + BB = dominant color kit (black, red)
Bb + Bb = dominant color OR recessive color kit (black, red OR blue, cream)
bb + bb = recessive color kit (blue, cream etc)