R. E. Gaensslen

A PCR-based strategy for ABO genotype determination.

The ABO blood group system has been widely used in forensic serology. Several techniques have been developed which detect ABH antigens. To overcome the problems associated with conventional methods such as bacterial contamination, extreme environmental conditions, antigen activity, non-secretor issues, and non-specific absorption, several new strategies have been employed to detect ABO genotypes by PCR. We have developed improved amplimers for the glycosyl transferase locus on chromosome 9 and examined the suitability of PCR-based ABO genotyping for forensic identification. We show that the ABO system is primate specific and that DNA extracted from various tissues commonly encountered in criminal cases can be quickly and reliably typed by ABO-PCR. The results indicate that ABO genotyping by PCR and restriction enzyme digestion of the amplified product is a useful procedure for forensic analysis that can provide additional discriminating power compared to conventional immunological methods.

Distributions of genetic markers in United States populations: III. Serum group systems and hemoglobin variants.

All published and unpublished population frequency data that could be located for U.S. populations are tabulated and presented for the serum group systems haptoglobin (alpha-chain), group specific component, and transferrin and for the common beta-chain variants of hemoglobin. Results obtained by combining data for comparable racial/ethnic groups are also presented. Some evidence is presented to indicate that the results obtained from the combined data may give better information on frequencies for the U.S. population at large than is obtainable from studies conducted in restricted geographic areas.

ABH Antigen Typing in Bone Tissue

Results obtained from the ABH grouping of bone tissues by the absorption-elution procedure and by a recently described two-dimensional absorption-inhibition procedure are reported. Neither the elution nor the inhibition procedure alone yielded uniformly correct results. A combination procedure consisting of the use of both absorption-elution and two-dimensional absorption-inhibition is proposed for bone ABH grouping. When elution and inhibition were used in combination, specimens yielding concordant results with both techniques were correctly grouped.

Distributions of Genetic Markers in United States Populations: I. Blood Group and Secretor Systems

All published and unpublished population frequency data that could be located for U.S. populations are tabulated and presented for the blood group and secretor systems. Results obtained by combining data for comparable racial/ethnic groups are also presented. The results obtained with combined data may give better information on frequencies for the U.S. population at large than is obtainable from studies conducted in restricted geographic areas.

Two-Dimensional Absorption-Inhibition

A novel inhibition procedure, called two-dimensional absorption-inhibition, is described. The theory underlying this technique is developed based on a review of and comparison with existing inhibition methods. Two-dimensional inhibition takes advantage of the best features of inhibition-titration and titration-inhibition, and is shown to be more sensitive than either of them. Results obtained using all the inhibition methods on secretor saliva, semen, urine, urine stain, and perspiration stain specimens show that the new technique is especially powerful in correctly determining the ABH antigens in secretor body fluids having lower concentrations of soluble blood group antigens. A two-stage version of the two-dimensional procedure that makes it a practical casework method is described as well.

Evaluation of antisera for bloodstain grouping. II. Ss, Kell, Duffy, Kidd, and Gm/Km.

Thirty-one different examples of commercially available blood grouping antisera specific for the S, s, K, k, Fya, Fyb, Jka, and Jkb antigens and anti-human globulin sera were serologically evaluated with red cells and in absorption-elution tests to determine their applicability to bloodstain antigen determinations. Nineteen examples of commercially available antisera specific for various Gm and Km antigens and their corresponding anti-D reagents were likewise evaluated in inhibition tests with sera and bloodstains. Elution tests with the blood grouping antisera and inhibition tests with the Gm/Km antisera on a series of aging bloodstains on cotton cloth, and on bloodstains on a number of different substrata, demonstrated that properly evaluated commercial antisera are useful reagents for bloodstain grouping in forensic serology.

Evaluation of Antisera for Bloodstain Grouping I. ABH, MN, and Rh

Sixty-eight different commercially available blood grouping antisera and lectins with ABH, MN, and Rh D, C, E, c, and e specificities were serologically evaluated for their applicability to bloodstain antigen determination. The characteristics of the antisera were determined with red cells, with fresh bloodstains, and with series of aging bloodstains. The Rh antisera were tested under a variety of serological conditions and with bloodstains on various substrata. Additionally, studies on optimization of absorption-elution procedure variables were carried out, and some data on the storage characteristics of red cells and blood grouping antisera were gathered.

Regional Cooperation and Regional Centers Among Forensic Science Programs in the United States

Various types of cooperative arrangements between the forensic science programs of colleges and universities are discussed as possible means of increasing student exposure to faculty expertise in specialized subject areas and of using more effectively the comparatively scarce resources of individual programs.

Genetic Markers in Human Bone: II. Studies on ABO (and IGH) Grouping

A combination absorption-elution, two-dimensional absorption-inhibition procedure was used to determine the ABH antigen composition of a series of human bone specimens of known ABO type that had been aged up to nine months under dry and humid conditions at ambient temperature, 37 degrees C, and 56 degrees C; at ambient temperature in dry and wet soil; and buried in soil outdoors. Grouping data for the separate elution and inhibition testing, as well as for the combination procedure, are given. The combination method was found to be a highly reliable procedure for bone tissue ABH typing. Some data on microbial contaminants of human bone specimens aging in soil, and their effects on ABH typing results, are presented. No direct correlation between the properties of microbial contaminants and specific changes in the ABH antigenic composition of aging bone tissue specimens could be ascertained. Data on IGH antigen determination and on the quantitation of immunoglobulin G (IgG) in human bone tissue extracts indicated that immunoglobulin levels were typically too low to expect routinely successful Gm antigen testing results. However, these factors can sometimes be determined in fresh bone tissue extracts, particularly if the extracts are concentrated.

Enzyme Assays for the Identification of Gastric Fluid

Simple, reliable procedures for the assay of pepsin and rennin-like enzyme activities are described as a means of identifying gastric fluid-containing samples in forensic science laboratories. These samples are usually vomitus, or stomach contents originating from wounds that perforate the stomach. They may be encountered at scenes or on articles submitted for examination, in fresh form or as dried stains. The pepsin activity assay is based on proteolytic activity with bovine albumin as substrate and the rennin-like activity assay is based on the coagulation of milk protein.