[Comparison study of the HUMFGA and HTPO STR system in the Saxon and Czech population]

High variability of repetitive DNA in a non-coding region of human genome affords possibilities for vestige identification and determination of their origin. For analysis of DNA many a time obtained from decomposed material, usually in a very small amount and sometimes partially degraded, polymerase chain reaction is considered as optimal technique. For identification of individuals is used an Amplified Fragment Length Polymorphisms (AmpFLP), which present repetitions 10 to 70 base pairs long in an amplification products of 170 to 1200 bp. In legal medicine PCR systems using tetrameric repetition polymorphism are widely used. These systems are highly sensitive, but in comparison to AmpFLP systems, imperceptibly influenced by nucleic acid degradation in cases of old or partially degraded samples. Aim of our study was to compare frequency data for 2 STR-systems, FGA and HTPO, both after PCR amplification, on 200 samples of Czech and 228 of German population. In FGA system of Czech population 14 different alleles and 44 genotypes were determined, while German population provided 13 different alleles and 47 genotypes. Furthermore, frequency of alleles and heterozygosity rate were determined. Heterozygosity rate for Czech samples was 85%, for German ones 87.1%. Alleles 21 and 22 were most frequent (approx. 20%) between both Czech and German population, followed by alleles 20, 23 and 24 (14-12%). Besides these data, three different transient alleles were detected. In HTPO systems of both population groups 12 different genotypes, consisting of 5 alleles, were determined. Genotypes 8/8 and 8/11 observed in 30% were the most frequent ones in both population groups. Heterozygosity rate for Czech samples was 62.5%, for German ones 65%. Results were statistically analyzed. In both population groups, no significant difference from Hardy-Weinberg's balance was found. Additionally, statistic parameters for forensic effectivity evaluation were constructed. Comparison of both populations using homogeneity tests provided non-significant difference. FGA system provides extraordinary high forensic exploitativeness and therefore is fully acceptable for vestige identification and determining of their origin. For significant determination of transient alleles analysis of fluorescein-labelled fragments in denaturing gel system should follow, using automated laser detection of fluorescence. Polymorphism of HTPO-system is significantly lower compared to FGA-system, but relatively small PCR product required as well as simple detection and imperceptible influence of nucleic acid degradation allow the use of HTPO for analysis of highly degraded DNA.