Edda Ambach, Walther Parson and Richard Scheithaur
Institute for Forensic Medicine, University Innsbruck, Austria

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In the analysis of biological samples submitted to DNA laboratories, sex determination is a very important element in providing forensic evidence.

Sex determination has already been described by Gill using Southern blotting (1). We currently use the amelogenin gene for sex determination. It represents a very sensitive system, enabling easy sex determination in single donor samples as well as a male component in mixed samples. However, due to the fact that it shows no polymorphism, amelogenin cannot distinguish between different males in mixed samples.

In our population study, we used 2 STRs to analyze the variability of the Y-chromosome (DYS19 and DYS389) in an Austrian population sample (2,3). DNA was extracted from blood samples of 70 unrelated males in a West-Austrian population. In addition, the two STR loci were studied in 20 father-son pairs, in whom paternity had been previously confirmed by serology and RFLP analysis.

Amplification was carried out applying a hot-start PCR. Alleles were separated in a 6% denaturing polyacrylamide sequencing gel, detected by fluorescence with a 373 A Stretch Sequencer (ABI) and sized by an internal lane standard with the GeneScan 672 Software (ABI) using the Local Southern method for band size estimation.

The Y genotypes of the 70 unrelated males met the expected and previously reported distributions (4). No mutation was detected within the father-son pairs. As the estimated rate of the Y haplotypes is low, it provides a record of male-specific gene flow through many generations.

The PCR-based analysis of different Y-chromosomal STRs provides a simple and sensitive male identification system for forensic applications.

REFERENCES

1. Gill P. (1987) A new method for sex determination of the donor forensic samples using a recombinant DNA probe.

Electrophoresis 8:35-38.

2. Roewer L., Arnemann J., Spurr N.K., Grzeschik K.H. and Epplen J.T. (1989) Simple repeat sequences on the human Y chromosome and equally polymorphic as their autosomal counterparts. Hum. Genet. 89:389-394.
3. Santos F., Pena S. and Epplen J. (1993) Genetic and population study of a Y-linked tetranucleotide repeat DNA polymorphism with a simple non-isotopic technique. Hum. Genet. 90:655-656.
4. Roewer L., Kayser M., Nagy M. and Knijf P. (1996) Male identification using Y-chromosomal STR polymorphism. Adv. Forensic Haemogenet. 6:124-126.