Examination of microchromosomes in birds has led to the hypotheses that they may have originated as conserved fragments of ancestral macrochromosomes, and conversely that macrochromosomes could have arisen as aggregates of microchromosomes.
O estudo dos microcromosomas das aves levou a formular a hipótese de que se puideron orixinar como fragmentos conservados de macrocromosomas ancestrais, e inversamente que algúns macrocromosomas puideron orixinarse como agregados de microcromosomas.