The Analysis Of Amelogenin Of Human 3000 Years Ago In Xi'an

With the continuous development of modern molecular biology and experimental technology, the studies of ancient DNA have been widely used in archeology, anthropology, biology, genetics, and many other fields. The aim of the study is to provide molecular biological evidence for identification of ancient human, migration of human, origin and evolution of creature, and heredity of disease.In the early stages of amelogenesis, enamel consists of 20~30% protein. Amelogenins are the most abundant protein constituents of the developing enamel, and during the first phases of mineral deposition may account for 60%~90% of the enamel matrix. In the process of enamel formation, enamel proteins, particularly amelogenins, may also play an important role in the formation of microstructural patterns and their evolution. Amelogenin has been seen as an important mark of species differentiation because it can be expressed in different species. Human amelogenin gene is a pair of alleles, which located at X and Y chromosomes. Study on the expression changes of amelogenin on the sex chromosomes has been an important method for sex identification. Our study established a convenient method for DNA extraction from ancient teeth. We extracted DNA from the teeth 3000 years ago and designing the specific primers of amelogenin to perform the sex typing. At the same time, we screened variations in the hypervariable region of human amelogenin 3000 years ago in the area of Xi'an and compared the frequency of different types of SNPs in amelogenin between 3000 years ago and modern man in the area of Xi'an.The main result of this study can be concluded as follows,1. The"Reverse-root-canal technique"and Chelex-100 were applied to extract DNA from the teeth samples, which were 3000 years ago in the area of Xi'an. The genomic DNA extracted from the samples had a high quality for PCR amplication and the teeth samples were low-destructive.2. The specific primers of amelogenin were designed and PCR method was used to perform the sex typing. Thirty samples obtained accurate results of sex identification in the study. Our results provide a convenient way for the future study.3. There were no variations in the hypervariable region of human amelogenin 3000 years ago in the area of Xi'an. This result is contrary to what was suspected from the evolutionary analysis.4. There were no significant differences of SNPs for rs6639060 and rs2106416 between 3000 years ago and modern in the area of Xi'an.In conclusion, the combination of"Reverse-root-canal technique"and Chelex-100 extraction is a reliable method for DNA extraction from ancient teeth, and the sex identification based on ancient DNA also shows the superiority of the traditional morphological identification methods. However, we need to perform further study on polymorphism in amelogenin of 3000 years ago in the area of Xi'an as well as the relationship between the structure and thickness of enamel and the polymorphism of amelogenin.