South American tapir
The Malayan tapir, the species most isolated geographically and genetically, has a significantly smaller number of chromosomes and has been found to share fewer homologies with the three types of American tapirs. A number of conserved autosomes (13 between karyotypes of Baird's tapir and the South American tapir, and 15 between Baird's and the mountain tapir) have also been found in the American species that are not found in the Asian animal. However, geographic proximity is not an absolute predictor of genetic similarity; for instance, G-banded preparations have revealed Malayan, Baird's and South American tapirs have identical X chromosomes, while mountain tapirs are separated by a heterochromatic addition/deletion.