Strengths and weaknesses associated with Y-STR genotyping

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Strengths and weaknesses associated with Y-STR
genotyping
Dan E. Krane Biological Sciences, Wright State
University, Dayton OH 45435

• Forensic Bioinformatics (www.bioforensics.com)
• help_at_bioforensics.com

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Y chromosome background

• A scanning electron micrograph of the human Y and
  X chromosomes in metaphase.

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Y chromosome details

• Hemizygosity first recognized in the 1920s
• 300 million years old
• Pseudoautosomal region is 1 to 2 different than
  X
• Intrachromosomal recombination
• 30 of 60 million base pairs sequenced

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X and Y chromosome genes

• Y contains at least 78 active genes (vs. 2,000 on
  X)
• 300 million years ago sex was environmentally
  determined
• Many male specific immigrants in the past 30 to
  50 million years

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Exclusive paternal inheritance
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Haplotype phylogeography
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High profile studies

• Thomas Jefferson and Sally Heming
• November, 1998 paper in Nature, accepted by the
  Jefferson foundation in 2000 then deemed not
  definitive in 2003.
• Europes ten men
• 8 Ys from 40,000 years ago and 2 from 8,000
• Cohanim are descendants of Moses brother
• 50 of Jewish priests (including the Lemba) have
  an unusual haplotype
• Adam (and Eve)
• Adam and Eve lived in Africa but probably never
  met (Nature Genetics, 2000)

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Commercialization genealogy
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Y-STR markers
Y-STR markers
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Italian Population Haplotypes
216 Unrelated Males
Y385
From Forensic Haemogenetic Laboratory Catholic
University of the Sacred Heart UCSC - ROME
http//www.mclink.it/personal/MD1696/data/
Y393
Y392
Y391
Y390
Y389II
Y389I
Y19
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Commercially available kits

• ReliaGene Y-PLEX6
• Tests DYS19, DYS385a/b, DYS389II, DYS390, DYS391
  and DYS393.
• ReliaGene Y-PLEX5
• Tests DYS389I, DYS389II, DYS392, DYS438 and
  DYS439.
• ReliaGenes Y-PLEX12
• Tests a total of 11 different loci (recommended
  by SWGDAM) including the 9 endorsed by the
  International Y-STR User Group plus amelogenin.

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Utility and Limitations of Y Chromosome STRs

• Utility for forensic applications
• 98 of violent crime by men
• Male component isolated without differential
  extraction
• Mixture deconvolution is simplified
• Limitations for forensic applications
• Paternal inheritance
• Limited resolving power
• Independence with autosomal loci?

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