Genus (music) the other hand, also has twelve pitches to the octave, but the semitones are all of the same size. In contrast, the ancient Greek chromatic scale had seven tones to the octave (assuming alternating conjunct and disjunct tetrachords), and had incomposite minor thirds as well as semitones and whole tones. The (Dorian) scale generated from the chromatic genus is composed of two chromatic tetrachords: whereas in modern music theory, a chromatic scale is: The number and nature of the shades of the chromatic genus vary amongst the Greek theorists. The major division is between the Aristoxenians and the Pythagoreans. Aristoxenus
Steps and skips step will always be a movement of 1 or 2 semitones, and a skip a movement of 3 or more semitones. In other scales an augmented second—an incomposite step equivalent to 3 semitones—and/or a diminished third—a skip of 2 semitones—may be possible. Melody may be characterized by its degree and type of conjunct and disjunct motion. For example, Medieval plainchant melodies are generally characterized by conjunct motion with occasional thirds, fourths, and generally ascending fifths while larger intervals are quite rare though octave leaps may occur between two separate phrases. Renaissance melodies are generally characterized by conjunct motion, with only