人基因组核小体DNA遗传标记筛选及其抗降解机制探究

The analysis of highly degraded DNA is always a major challenge for forensic genetics. Nucleosome is the subunits of all chromatins. There are some circumstantial evidence suggested that the protective capabilities of nucleosomes probably exist. And our preliminary experiments also confirmed the hypothesis. In this study, we want to explore the relative stability of the nucleosome positioning of human lgenome by increasing the number of high-throughput sequencing samples and cross matching; And to verify protective capabilities of the genetic markers in the core region in a large scale which could further complete our preliminary experimental conclusion that“the protective capabilities of nucleosomes core region is more than the linker region ”；Accurate screening of nucleosome genetic markers can provide a theoretical basis and data sources for degraded DNA analysis；we will also sequence the degraded samples and analyze the relationship between degraded DNA fragments and the preference of enzymes released by microorganisms，which could further reveal the mechanism of nucleosome core DNA resistant against degradation and to provide a new strategy and direction of degraded DNA analysis.

降解DNA的分型一直是法医DNA检验的难点。核小体作为真核染色质基本重复结构单元，有多方面证据表明与连接DNA相比，核心DNA更易抵抗降解。我们的前期实验也初步证实了这一假设。本研究通过增加高通量测序样本数量，进行交叉比对，确定相对稳定的核小体缠绕定位区域；并对所获核小体核心区域遗传标记进行验证，从而进一步完善“核小体核心DNA更易抵抗降解”这一结论；实现核小体遗传标记的精确筛选，为建立高效的降解检材分析遗传标记数据库奠定理论基础并提供准确的数据来源；提取陈旧自然降解检材DNA进行测序，分析自然降解检材DNA片段的序列规律与微生物释放的核酸酶作用偏好性之间的关系，深入探讨核小体核心DNA抵抗降解的机制。并为降解DNA的检验提供全新的技术手段及发展方向。