Regional Italian allele frequencies at nine short tandem repeat loci

Allele frequencies for nine STR loci (D3S1358, vWA, FGA, D8S1179, D21S11, D18S51, D5S818, D13S317, D7S820) in the Italian population

Genotype and allele frequencies for STR loci D3S1358, vWA, FGA, D8S1179, D21S11, D18S51, D5S818, D13S317, D7S820 were investigated in 289 unrelated Italian Caucasian individuals from the North and South regions. After co-amplification by polymerase chain reaction, automatic DNA profiling of these nine STR loci was performed by ABI PRISM((R)) 310 DNA Genetic Analyzer. For each locus, statistical parameters for forensic and paternity purposes were then calculated; the combined power of discrimination and the combined power of exclusion of all nine loci were 0.9999999999917 and 0.99992 for the Northern population and 0.9999999999921 and 0.99991 for the Southern population.

Validation of a large Italian Database of 15 STR loci

Results from a collaborative exercise with proficiency testing conducted by 20 Italian laboratories on the 15 loci included in the Identifiler kit were analyzed by allele sharing methods and by standard population genetics tests. The validated database, including about 1500 subjects, was merged with that of a previous exercise conducted on nine loci, and the resulting allele frequencies, subdivided by Italian region, were published on-line.

Typing of 20 Y-chromosome STRs in the Italian population

The aim of the present study is to appraise the increase of the discrimination power of the Y-specific haplotype allowed by 20 STR markers in a sample of the Italian population. The set of Y STR markers analyzed includes the European "extended haplotype" DYS19, DYS385, DYS389I/II, DYS390, DYS391, DYS392, DYS393 and YCAII a/b and in addition the DYS437, DYS438, DYS439, DYS447, DYS448, DYS388, DYS426, DYS460 (Y-GATA-A7.1) and Y-H4 loci.

Demonstration of a Gastric Bioptic Specimen Mix-up by Laser Capture Microdissection (LCM) and DNA Fingerprinting

We demonstrate here the successful use of laser capture microdissection (LCM) and DNA fingerprinting in the identification of a case of gastric bioptic specimen mix-up. A 70-year-old man, suffering from chronic atrophic gastritis, underwent to a gastric biopsy and received a diagnosis of gastric cancer. In the absence of any clinical evidence of gastric cancer, a specimen mix-up was suspected. LCM was used to retrieve gastric cells from the histologic slide, classified as gastric carcinoma, and suspected to be mislabelled. DNA was extracted from microdissected cells, and a total of 16 different genetic loci were analyzed, using an identity test. Comparison of the results with those obtained using DNA extracted from a control slide, and from patient's saliva, demonstrated a distinct DNA fingerprint pattern in all genetic markers examined, clearly indicating the occurrence of a specimen mix-up. The combined use of LCM and DNA fingerprinting represents the most accurate and sophisticated method available for the identification of specimen mix-up, especially when only the tissue on the suspected slide is available.

DNA identification of sperm cells collected and sorted by flow cytometry

In cases of rape, obtaining enough biologic material for DNA identification of the attacker is often difficult because the methods for distinguishing and separating sperm cells from vaginal cells are not sufficiently efficacious. This article describes a new, innovative method for spermatic DNA extraction from the vaginal washing fluid by means of flow cytometry. The high specificity and sensitivity of the flow-cytometric sorting method provides enough sperm cells for DNA typing. The ease of execution of this method, involving vaginal washing with physiologic solution and flow-cytometric reading of the fresh sample, substantially increases its cost-benefit ratio.

Allele sharing in first-degree and unrelated pairs of individuals in the Ge F I AmpFlSTR Profiler Plus database

Eleven Italian forensic laboratories participated in a population study based on the AB Profiler Plus loci with proficiency testing. The validated database, including 1340 individuals, is available on-line. Tests for Hardy-Weinberg equilibrium, gametic unbalance, and heterogeneity of gene frequency were generally not significant. Gene frequencies at each locus were consistent with those of two previously published Italian studies, but different from a third. Individuals of each subsample were paired, and the total number of alleles shared across the nine loci was determined in each pair. The analysis was replicated over the total sample. In addition, two samples of mother-child pairs (N=315) and full-sib pairs (N=91) were subjected to allele sharing analysis. The resulting distributions were sufficiently distinct from the sample of unrelated pairs as to be of practical usefulness.

Population variation at the CODIS core short tandem repeat loci in Europeans

Substantial STR population data exist to estimate F(ST) (or theta) values across Europeans. Eleven populations across Europe were analyzed, and the estimate over all 13 CODIS core STR loci is 0.0028. This value is much less than the conservative estimate of 0.01 advocated by the second National Research Council Report in 1996. Because of the low value for theta, whether independence is assumed or an adjustment for substructure is employed, there is little practical consequence for forensic purposes for estimating the frequency of a multiple locus DNA profile. If theta is used, a value of 0.01 is very conservative for Europeans. The same STR population data can be used for evolutionary studies on Europeans, and the calculated genetic distances are consistent with the ethnohistory of the populations.