The common ancestor of hominoids is shown to have a minimum of 24 major chromosomal rearrangements from the presumed gibbon ancestor’s karyotype. To reach the common gibbon ancestor’s karyotype from today’s various living species of gibbons, it will require up to 28 additional rearrangements. Adding up, this implies that at least 52 major chromosomal rearrangements are needed to compare the common hominoid ancestor to today’s gibbons. No common specific sequence element in the independent rearrangements was found while 46% of the gibbon-human synteny breakpoints occur in segmental duplication regions. This is an indication that these major differences in humans and gibbons could have had a common source of plasticity or change. Researchers view this unusually high rate of chromosomal rearrangement that is specific in small apes like gibbons could potentially be due to factors that increase the rate of chromosomal breakage or factors that allow derivative chromosomes to be fixated in a homozygous state while mostly lost in other mammals.