Slominsky P.A., Shadrina M.I., Shulskaya M.A,
Institute of molecular genetics RAS, Moscow.
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MOLECULAR-GENETIC ANALYSIS OF PALEODNA IN THE STUDY OF THE OICUMENE SETTLEMENT HISTORY: POTENTIAL AND LIMITATIONS.*
*The study was partially financed with the RFPF-YNAO grant 16-44-890212.
Recent developments in the humans' genetic studies made possible establishing the degrees of genetic kinship between the modern ethnic groups and identify the possible routes for the formation of the gene pool of the modern population of the Oicumene. The results of such studies have been based on the analysis of DNA of the currently living people. For their verification purposes it was extremely important to be able to perform a comparative study of the DNA of the modern people and the previous populations obtained from different tissues (primarily from the bone tissue). This analysis will allow monitoring certain ethnic groups' gene pool dynamics in the course of history, trace the relationship between the gene structure of the ancient populations and certain cultural specifics, identify the changes in the genetic traits of the population of a particular territory in an historical perspective.
Any study of ancient DNA (aDNA) obtained in the course of archaeological excavations of biological remains is based on the DNA extraction method which allows obtaining the maximum aDNA quantity with the minimum risk of its contamination with the modern DNA. The selection of a particular extraction method depends on the type and the nature of the biological material. We have performed a comparative analysis of a number of aDNA extraction methods from the mummified soft tissues of the Ob Ugrians discovered in the course of archaeological excavations of Zeleny Yar site. As a result we have developed a complex method with a combination of nucleic acid extraction with a phenol/chloroform mixture and the subsequent purification and concentration of aDNA with the use of microcolumns. So far we have succeeded in extraction of aDNA from one of the mummies and perform its amplification with primers into the mitochondrial and the genome DNA. A successful amplification was obtained only for the short amplicons (not more than 150 bps) both for the mitochondrial and the genome DNA. The DNA yield turned out to be quite low - not more than 5-10 ng of DNA per 100 mg of tissue. The low yield may be the result of low acidity of the soil in the place of burial and the use of birch bark for wrapping of the body prior to deposition. It is possible that with time a triterpene compound betulin is extracted from the bark in acid environment, which may affect the chemical reaction or block the amplification process. At the same time the extracted DNA substances contained the PCR blocking low-molecular compounds, therefore for the successful amplification reaction the DNA must be diluted to concentrations of at least 0.1 ng/mcl.