1. Y-STR POLYMORPHISMS IN FORENSIC CASEWORK Mgr. Jana Odlerová Institute of Forensic Science Slovak Police Corps

2. Y Chromosome -small ~60 Mb total DNA sequence (only chromosome 22 is smaller) - acrocentric - linear DNA - haploid - uniparental lineages - male-specific - genetic variation at multiple points along the Y chromosome is combined to form a Y haplotype for a sample

3. Y chY ch Ľudský X a Y chromozóm Human X a Y Chromosome ~ 2.5 Mb on tips recombine with X (pseudoautosomal regions) ~ homologous regions on human X and Y chromosome except pseudoautosomal regions

4. Why the Y Chromosome? Applications - forensic investigations (98% of violent crime by men) - genealogical purposes - evolutionary studies Advantages to Human Identity Testing - male component isolated without differential extraction - paternal lineages Needs - population studies to evaluate diversity of haplotypes - robust assay for accurate characterization of Y markers

5. Y Chromosome DNA Markers STRs (microsatellites) - DYS19, DYS385, etc. - mostly tetranucleotide repeats Bi-allelic markers (unique event polymorphisms--UEP) - SNPs (single nucleotide polymorphisms) - Y Alu polymorphism (YAP) or other insertions/deletions (“indels“) Minisatellites - MSY1 (DYF155S1) composed of 48-114 copies of a 25 bp repeat unit with 5 sequence variant repeat types - typed by MVR-PCR (minisatellite variant repeat)

6. Map of Y Chromosome STR Markers

7. Y-Plex™6 - include 6 Y-STRs (Reliagene Technologies, Inc.) Y-Plex™5 - include 5 Y-STRs (Reliagene Technologies, Inc.) PowerPlex™Y System - include 11 Y-STRs (Promega) Y-Plex™12 - include 11 Y-STRs + amelogenin (Reliagene Technologies, Inc.) AmpFLSTR Yfiler™ PCR Amplification Kit - 17 Y-STRs (Applied Biosystems) Current Forensic Y STR Multiplexes

9. Advantages of Using Y Chromosome in Forensic Casework - limited amount of biological material (optimal is 0,3 ng DNA) - partially degraded DNA - absence of consanguineous biological relatives – parents, children - mixtures of DNA in rape cases (15 pg male DNA:150 ng female DNA) - mixtures of DNA from three or more individuals (at least one man) - male DNA present at trace levels Disadvantage – individual identification

12. THANK YOU FOR ATTENTION