According to archaeological data, the territory of Mongolia was inhabited 700.000 years ago. It has been hypothesized that nomadic hunter-gatherer groups migrated across Mongolia, Siberia, Russian Far East, Southeast Asia and Middle Asia. A large number of ethnicities inhabited Mongolia since prehistoric times were mostly nomads who, from time to time, formed great confederations that rose to prominence. Human remains belonging to different historical periods of Mongolia have been studied. Based on the results obtained from craniofacial studies of prehistoric remains in Mongolia, scholars concluded that prehistoric populations of Mongolia reveal great heterogeneity of morphological traits. People with Caucasoid morphological features inhabited Western Mongolia while populations with developed Mongoloid traits occupied central and eastern Mongolia. However, the western Mongolian population of the Bronze Age exhibited more pronounced Mongoloid morphological features than seen in earlier times. It can be hypothesized that the Early Bronze Age was characterized by movements from eastern Mongolia to western Mongolia where intensive intermingling between local Caucasoid and Mongoloid populations took place.
Mongolian scholars carried out a comparative study of Neolithic, Bronze and Early Iron Age populations of Mongolia and Northeast Asia to clarify the historical and biological relationships between those populations in Asia. The results of the comparative analysis show that the ancient and contemporary populations of Mongolia are divided into two clusters. The first cluster includes all historical populations from east and central Mongolia, and it may indicate the genetic relations of those populations of Mongolia. However, the second cluster includes Neolithic, Bronze and Iron Age populations from western Mongolia. Comparative morphological analysis shows that the Neolithic populations in Asia are divided into two major clusters. The first cluster includes all populations from the Lake Baikal region, Eastern Siberia, the Amur River basin and Japan. However, the populations from western Mongolia and Altai occupy a separate position in this cluster. The second cluster includes populations from China and Korea. Surprisingly, the Neolithic populations from East Mongolia and Promor'e are distinct from other Asians.
Comparison of Asian Bronze and Early Iron Age populations shows that these populations are divided into five major clusters except for the population from Manchuria. The first cluster combines most of the populations from West Mongolia, the Altai mountain region, South Siberia, Korea and Japan (Yayoi period), but in turn the first cluster divides into three subclusters. The second cluster includes populations from Inner Mongolia, Central and Northwest China. The populations from Altai (Afanasevo culture), North Kazakhstan (Usunian culture) and South Siberia (Minusinsk culture) belong to the third cluster. The populations from the slab grave culture from East Mongolia and Karasuk culture from Central Tuva belong to the fourth cluster. The fifth cluster combines the populations from Cis-Baikalia (slab grave culture), Minusinsk (Okunevo culture) and West Mongolia (culture of graves with no inventory). The separation of Bronze Age populations from Northeast Asia into several clusters and subclusters may show intensive intermingling of the Caucasoid and Mongoloid populations during this historical period.