Mitochondrial DNA sequencing of human hair shafts stored for long time

Mitochondrial DNA (mtDNA) sequencing is commonly used for forensic genetic identification of relation and personality identification based on analysis of tooth and skeletal rudiments. We demonstrated the possibility of DNA extraction and subsequent enzymatic amplification of fragments of a hypervariable segment I of mtDNA control region from hair shafts after long storage (up to 75 years). Shed hairs are the most common biological material evidence in forensic investigations. Low content of DNA and its possible degradation in hair shafts without bulbs may cause artifacts in polymerase chain reaction. However comparative analysis of amplified nucleotide sequences of amplified fragments from hair stored for 75 years was identical to the sequence from hairs cut immediately before experiment. This indicates high quality of the resultant matrices, stability of results, and hence, the possibility of using DNA extracted from hair shafts without bulbs stored for a long time for expert genetic analysis. Theoretical and methodological prospects of using mtDNA polymorphism analysis for forensic expert evaluations are discussed.     

Probability of default models of Russian banks

This paper presents results from an econometric analysis of Russian bank defaults during the period 1997–2003, focusing on the extent to which publicly available information from quarterly bank balance sheets is useful in predicting future defaults. Binary choice models are estimated to construct the probability of default model. In the first part of the paper we analyse bank survival over the financial crisis of 1998. We find that preliminary expert clustering or automatic clustering improves the predictive power of the models and incorporation of macrovariables into the models is useful. Heuristic criteria are suggested to help compare model performance from the perspectives of investors or banks supervision authorities. In the second part of the paper we use the probability of default models developed in the first part in rolling windows to analyse the Russian banking system trends after the crisis 1998.