Degradative factor analysis of ancient DNA preserved in human bones

    YANG Zhouª²Qi, ZHANG Huª²Qin,ZHANG Jin, ZHAO Wenª²Ming

    Key Laboratory of Biomedical Information Engineering of Ministry of Education, Bioinformatics Research Center, School of Life Science and Technology, Xi¬ðan Jiaotong University, Xi¬ðan 710049, China

    ¡¾Abstract¡¿ The ancient DNA (aDNA), the most important genetic information of ancient human, has been widely used in the studies of human origin, evolution, racial character, migration and diseases, and herefrom the molecular archaeology has developed rapidly. By virtue of its special structure and physical specialty, the bones have often been selected as the ideal aDNA samples. Effected by the outside physical and chemical factors, enzymes and microorganism, the aDNA preserved in human bones will get degraded into small fragments during a long buried or exposed time. By analyzing the structure and specialty of bones, we discussed the preservation of bone structure and the effects of environmental factors on its decomposition and investigated the adsorption effect of matrix framework formed by bone inorganic phase hydroxyapatite and collagen via calcium bridge on aDNA fragments. Based on the analysis of the characteristics and stability of DNA, we discussed the damages of hydrolyzation, oxidation, enzyme and microorganism to aDNA and studied the influences of the environmental factors inclusive of temperature, humidity, pH value and microorganism on aDNA degrading rate. In the end, the survival age limit and the favorable preservation conditions of aDNA were suggested to provide theoretical evidences for the extraction, preservation, sampling and authenticity evaluation of aDNA. ......