Forensic DNA identification of animal-derived trace evidence: tools for linking victims and suspects.
OBJECTIVE
To evaluate the population substructure of purebred dogs and cats in order to estimate the true significance of a microsatellite-based DNA match for use as evidence in legal proceedings. The high frequency of animal hair as a forensic evidence submission necessitates the development of mitochondrial analysis tools as well.


METHODS
Random samples from a large convenience collection of veterinary diagnostic submissions from the western USA were used, as well as contributed samples of unrelated purebred cats and dogs. Dogs (n=558) were profiled with 17 microsatellites and the data evaluated for Hardy Weinberg and linkage equilibrium. The mitochondrial control region (D loop) of dogs (n=348) and cats (n=167) was sequenced to determine the haplotype distribution.


RESULTS
Domestic dogs in the western United States showed significant population substructure with marked associations within loci but no disequilibrium between loci. A population substructure coefficient Theta=0.11 is recommended for calculating genotype frequencies. Mitochondrial haplotypes in cats and dogs show less variation than human haplotypes.


CONCLUSIONS
Although population substructure occurs in domestic dogs (and can be inferred in cats), the discriminatory power of microsatellite analysis is dramatic with even partial DNA types, strongly supporting the prosecution of perpetrators in five discussed cases. Mitochondrial analysis, while less powerful, adds a layer of evidence in four discussed cases.
Halverson
Joy L
JL
QuestGen Forensics, 29280 Mace Blvd., Davis, CA 95616, USA. questgen@zoogen.biz
Basten
Christopher
C
D000818:Animals; D002415:Cats / Q000235:genetics*; D019548:Crime Victims; D003418:Criminology / Q000379:methods; D004247:DNA / Q000235:genetics*; D004285:Dogs / Q000235:genetics*; D005554:Forensic Medicine; D014481:United States
D004247:DNA