Marilyn Menott-Raymond¹, Victor A. David², J. Claiborne Stephens¹, Leslie A. Lyons¹ and Stephen J. O’Brien^1
1 Laboratory of Viral Carcinogenesis, NCI-FCRDC, Frederick, MD
² Intramural Research Support Program, SAIC-Frederick, NCI-FCRDC, Frederick, MD

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Hairs of domestic animals are frequently associated with crime scenes; however, morphological examination generally results in identification largely at the species or breed level. We present a PCR based method of genetic individualization of domestic cats which has been applied to the forensic analysis of single hair specimens. Ten feline STR loci were selected from a subset of 400 dinucleotide (dC-dA)_n - (dG-dT)_n repeat loci isolated from genomic DNA of Felis catus which had been mapped in a 70 member pedigree. The STR loci were unlinked, demonstrated Mendelian inheritance, exhibited high heterozygosity and amplified with as little as one nanogram of DNA, generating strong, clean electrophoretogram profiles. A "match window" was empirically established for each STR locus based on determining the measurement precision of alleles know to be unambiguously identical by descent in the three generation pedigree. A genotype survey of two small population groups was performed which demonstrated that the 10 loci exhibit expectations consistent with Hardy-Weinberg equilibrium. We present a conservative approach to compute, for forensic consideration, the mathematical likelihood of a chance genotypic match between evidentiary and suspect composite STR genotypes for species or populations where an extensive population genotype database is not available.