[Personal identification using information from cranio-facial region].

Much of Forensic Odontology is concerned with personal identification, through examination of cranio-facial region. This paper describes several studies in which we worked with materials derived from cranio-facial region. The following topics are addressed : (1) Human saliva contains proteins specific to salivary glands, proteins which are highly polymorphic compared with those found in other body fluids. In particular, six genes for proline-rich proteins coded many proteins found in human saliva, and we found several of them. At least five kinds of cystatin are secreted in saliva. We constructed recombinant polymorphic proteins, cystatin SAl and SA2. Using these proteins, we compared effects of amino acid mutation on protease inhibitor activity, and demonstrated a novel function for type-2 cystatin cytokine-inducing activity. (2) Among autosomal STR loci, we identified the D12S67 locus as highly polymorphic, with a heterozygosity of 95%, by investigating differences in nucleotide repeat units. Highly polymorphic autosomal STR loci offer an effective forensic tool under certain conditions, in addition to multiplex PCR, and therefore merit further study in forensic practice. (3) Although digitalization is prevalent in photography, analog images are preferable in certain circumstances as they offer better resolution. (4) Usually, information on mtDNA polymorphisms from HV1 and HV2 in the control region is used in forensic practice. However, information from the coding region considerably increases the discrimination power of mtDNA polymorphisms. It is important to increase the volume of coding region information available with regard to mtDNA polymorphisms for future forensic practice. (5) Y-STR polymorphisms are closely associated with binary haplogroups, and it is possible to estimate a binary haplogroup from an STR haplotype. (6) Mitochondrial DNA and Y-chromosomal polymorphisms can be used to determine geographic origin in individuals from East Asia, something that was considered difficult in the past. (7) A Dental Scan was constructed for the preparation of dental records. It offers a superior method to the taking of pictures as is done in standard forensic odontology.