[Possibilities of molecular genetic determination of age of an individual from biological traces].

Unlabelled: Application of molecular genetic methods during the examination of biological traces is irreplaceable for individual identification of their originators. However, this analysis does not provide any clues for further investigation without the possibility to compare the genetic profile of the examined trace with the profile of its potential originator. The age of a searched person represents an important entry for investigators. In this review, the recent methodical molecular genetic approaches are discussed with regards to their practical outputs leading to the estimation of biological age of an individual. The length of telomeric sequences and their attritions correlating with increasing age seemed to be very promising marker if they have been examined using Southern blot analysis. This method is not suitable for forensic casework due to the need of high amounts of DNA input. Recent methods based on quantitative polymerase chain reaction (qPCR) are applicable on samples with minimal DNA concentrations but they provide inconclusive results with regard to the age estimation based on the length of telomeres. Therefore novel methodical approaches were developed. Application of methods based on the examination of deletions in mitochondrial DNA, on the presence of transcripts of gamma hemoglobins or on the quantification of byproducts of somatic rearrangements of genes for T-cell receptors is restricted to special types of biological traces. The age dependent methylation of specific nucleotides in selected gene sequences seems to be the only promising universal marker.

Keywords: age estimation - molecular genetics - telomere attrition - qPCR - array technology - promoter methylation.