一项至今难以超越的古代中国科技成就（A technological achievement in ancient China that has so far been difficult to surpass）.docVIP

一项至今难以超越的古代中国科技成就（A technological achievement in ancient China that has so far been difficult to surpass） A mule is a hybrid of new varieties of biological science and the formation of. Horse and donkey are two different species in the genus of horse in animal taxonomy, and their relationship is remote. The hybridization between them is distant hybridization. According to the principle of genetics, it is difficult to produce individuals with normal vitality because of hybridization above the crossing degree, so hybridization is difficult to succeed. The horse and donkey although belong to distant relationship, but because of their genetic matrix with two kinds of animal reproductive cells generate new zygote ability of sperm egg binding to the normal zygotic division, and the absorption of nutrients in utero development to have the vitality of normal individuals. In China, the domestication of horses was completed six or seven years ago. About 6500 years ago the Banpo cultural relics unearthed a dent and horse bone. In Shandong, Henan, Tangyin Licheng chengziya, Jilin Bai Ying Chang Gang Zi, Gansu Fuyu North Yongjing Ma Wan, all these unearthed from about 4500 to 4000 years of cultural relics in the horse bone. This shows that to the late Longshan culture period, northern China has been domesticated horses. The ass tamed sooner than the horse. During the Longshan culture, there were donkeys in the domesticated animals of china. The distribution of the surface to surface than the donkey is much narrower. Ancient China was not only no donkeys in Guizhou, but also vast areas of central plains without donkeys. The domestication of donkeys was accomplished by minorities living in the Northwest territories. Horses and donkeys grow in the northwest. In the natural state, they have the opportunity to contact themselves and produce crossbred offspring - mules. Xie Zhaozhe in the Ming Dynasty, Five miscellanies about the mule said: North Hun, a science of travel, self interse