In the West, the Yuezhi people are called the Tocharians, and have this definition: a branch of the primitive Indo-Europeans, originating from the Ural Mountains and southern Siberia, going south into the Tarim Basin, and finally East to the Hexi Corridor. During the Han Dynasty, the Yuezhi people were defeated by the Huns and moved westward, conquered Bactria and the Ganges River Basin, and established the Kushan Dynasty. The Y chromosome of the Tocharians is haplogroup R1a1a-M17.
A more detailed discussion is as follows: The Tocharians are one of the earliest ancient peoples to settle in the north and south of the Tianshan Mountains. Their traditional territory is in the Taklimakan Desert. To the north of the boundary is the Tianshan Mountains, to the south is the Kunlun Mountains, and the boundary is To the east is the Gobi Desert and to the west is the Pamir Plateau. The Kucha and Yanqi people in the southern foothills of the Tianshan Mountains, the Cheshi people in the Turpan Basin and the Loulan people in the eastern Tarim Basin are all Tocharians.
The Tocharians described in Chinese records are people with big beards, deep eye sockets and high nose bridges. They played an important role in the emergence and development of the civilization of the Western Regions and even the entire Chinese civilization. Wheat that originated in West Asia was introduced to China from the West by the Tocharians. The Loulan civilization with a thousand-year history of civilization, the Qiuci civilization that has had a significant impact on the history of Chinese Buddhism, and the Turpan civilization that integrates various cultural factors from the East and the West were also created by the Tocharians.
However, there are great differences in the understandings of Chinese and foreign scholars about the origin of the Yuezhi people. The theory that seems to be prevailing is that the Tocharians belong to an early branch of the Indo-European people, and are different from the later Iranians, Greeks, Latins and Germans.
As an early-dispersing Indo-European-speaking ethnic group, they migrated eastward and southward in large numbers during the last global spread of Indo-Europeans. The main direction is to enter northern India and western and remote areas of northern China.
There are also different voices, namely the theory of Chinese native origin. That is to say, the Yue clan is the "Yu clan" in "Yi Zhou Shu Wang Hui Jie" and the "Yu Zhi" or "Yu clan" in "The Biography of Emperor Mu". Regarding their ethnic origin, ancient Chinese books such as "Wei Lue" call them Qiang people, and "Old Tang Book" calls them Rong people. "Book of the Later Han·Biography of the Western Qiang" records that the Yuezhi's "clothing, food, and language are slightly the same as those of the Qiang", indicating that the language of the Yuezhi probably belongs to the Sino-Tibetan language family.
In addition, A.K. Narain, a professor at the University of Wisconsin in the United States, proposed in 1990 that the Indo-European language groups themselves were formed in today’s western China, because the Yuezhi people have lived there since ancient times. To the west of the Yellow River and in the western regions of China. Some Chinese scholars even believe that they originated in Shanxi, China.
These arguments are very good, at least it shows that before there was no concept of country, human beings had completed the integration of human races. Therefore, it is a mistake to apply the concept of country to ancient human races. Before there was a country, the yellow and white races were already spread across the East, and they appeared in a fusion manner. Therefore, when studying the identity issues of these people, we might as well look at their own attitudes after the emergence of the concept of nation.