Development of an Italian RM Y-STR haplotype database: Results of the 2013 GEFI collaborative exercise.

Recently introduced rapidly mutating Y-chromosomal short tandem repeat (RM Y-STR) loci, displaying a multiple-fold higher mutation rate relative to any other Y-STRs, including those conventionally used in forensic casework, have been demonstrated to improve the resolution of male lineage differentiation and to allow male relative separation usually impossible with standard Y-STRs. However, large and geographically-detailed frequency haplotype databases are required to estimate the statistical weight of RM Y-STR haplotype matches if observed in forensic casework. With this in mind, the Italian Working Group (GEFI) of the International Society for Forensic Genetics launched a collaborative exercise aimed at generating an Italian quality controlled forensic RM Y-STR haplotype database. Overall 1509 male individuals from 13 regional populations covering northern, central and southern areas of the Italian peninsula plus Sicily were collected, including both "rural" and "urban" samples classified according to population density in the sampling area. A subset of individuals was additionally genotyped for Y-STR loci included in the Yfiler and PowerPlex Y23 (PPY23) systems (75% and 62%, respectively), allowing the comparison of RM and conventional Y-STRs. Considering the whole set of 13 RM Y-STRs, 1501 unique haplotypes were observed among the 1509 sampled Italian men with a haplotype diversity of 0.999996, largely superior to Yfiler and PPY23 with 0.999914 and 0.999950, respectively. AMOVA indicated that 99.996% of the haplotype variation was within populations, confirming that genetic-geographic structure is almost undetected by RM Y-STRs. Haplotype sharing among regional Italian populations was not observed at all with the complete set of 13 RM Y-STRs. Haplotype sharing within Italian populations was very rare (0.27% non-unique haplotypes), and lower in urban (0.22%) than rural (0.29%) areas. Additionally, 422 father-son pairs were investigated, and 20.1% of them could be discriminated by the whole set of 13 RM Y-STRs, which was very close to the theoretically expected estimate of 19.5% given the mutation rates of the markers used. Results obtained from a high-coverage Italian haplotype dataset confirm on the regional scale the exceptional ability of RM Y-STRs to resolve male lineages previously observed globally, and attest the unsurpassed value of RM Y-STRs for male-relative differentiation purposes.

Deletion of amelogenin Y-locus in forensics: literature revision and description of a novel method for sex confirmation.

Today, the molecular technique routinely for sex determination in forensics is based the detection of length variations in the X-Y homologous amelogenin gene (AMELX and AMELY). In humans, the amelogenin gene is a single-copy gene located on Xp22.1-Xp22.3 and Yp11.2; the simultaneous detection of the X and Y alleles using polymerase chain reaction (PCR) can lead to gender determination. Several studies have shown that normal males may be typed as females with this test: AMELY deletions may result in no product of amplification and normal males being typed as female as a result of the test (negative male). Considering the consequences of the result obtained using only the amelogenin marker, and the related potential difficulties in interpreting the results, the gender misinterpretation may be troublesome in clinical practice and in forensic casework. In this article, beginning with a review of the incidence of gender-testing failures among different populations, and with the different strategies proposed in the literature in case of doubt regarding the presence of deleted AMEL in the DNA profile, we propose a method for the identification of samples with deleted AMEL that can be applied, as an additional assay, in case of doubt regarding PCR results of sex determination.

Sex chromosome analysis in Turner Syndrome by a pentaplex PCR assay.

In this study, we describe a pentaplex PCR to determine the parental origin of the X chromosome and the presence of mosaicism, via amplification of four polymorphic markers located along the X chromosome (DXS10011, DXS6807, HUMARA, DXS101) and the X-Y amelogenin marker, in 41 families having a daughter with Turner Syndrome. Our results confirmed the cytogenetic findings and we found that the parental origin of the single X chromosome to be maternal in 84% of cases.

Role of metallothionein against oxidative stress in the mussel Mytilus galloprovincialis.

Metallothionein (MT) is a sulfhydryl-rich protein involved mainly in heavy metal homeostasis and detoxification. In this study, the use of the mussel as an experimental model allowed us to test MT antioxidant properties at the molecular, cellular, and organism level. MT induction was achieved by mussel exposure to Cd (200 microg/l) in aquaria for 7 days followed by detoxification in the sea for 28 days. Cd-preexposed and nonexposed mussels were then treated with Fe (300-600 microg/l) in aquaria for 3 days. Biochemical assays on digestive gland tissue showed that treatment with Fe led to a significant increase in oxyradical production and malondialdehyde level only in mussels not preexposed to Cd. The Cd-dependent resistance to oxidative stress was ascribed to MT induction, as Cd produced no significant variation of reduced glutathione and major antioxidant enzymes. Digital imaging of isolated digestive gland cells showed lower oxyradical rise and higher viability in cells from Cd-preexposed mussels after treatments with 0.5-5 mM H2O2. Analyses on whole organisms showed that anoxic survival was lowered in mussels that had been treated with Fe, but such an effect was less pronounced in Cd-preexposed mussels compared with nonpreexposed ones. In conclusion, data suggest an antioxidant role for MT, which seems to occur through oxyradical scavenging and is able to protect both isolated cells and the entire organism from oxidative stress.

Effects of free oxygen radicals on Ca2+ release mechanisms in the sarcoplasmic reticulum of scallop (Pecten jacobaeus) adductor muscle.

In vitro oxyradical effects on SR Ca2+ regulation were studied by using a SR-containing cell-free preparation from scallop (Pecten jacobaeus) adductor muscle. Ca2+ variations were fluorimetrically detected after incubation with Fluo-3 in the presence of ATP. Exposure to Fe3+/ascorbate produced dose-dependent Ca2+ release from SR vesicles, eventually leading to massive Ca2+ loss. Exposure to hypoxanthine/xanthine oxidase also caused Ca2+ release but at a much slower rate. Pre-incubations with catalase or with the hydroxyl radical scavenger KMBA led to a significant decrease in the Fe3+/ascorbate-induced Ca2+ release rate and to a delay of massive Ca2+ loss. Pre-incubations with GSH or DTT strongly reduced the Ca2+ release caused by Fe3+/ascorbate and, moreover, they prevented massive Ca2+ loss from SR vesicles. Addition of GSH or DTT after Fe3+/ascorbate promptly reduced the Ca2+ release rate and delayed massive Ca2+ release. Pre-incubation with the SR Ca2+ channel blocker ruthenium red strongly reduced the Ca2+ release caused by Fe3+/ascorbate, and also prevented massive Ca2+ loss. In the presence of ruthenium red, Fe3+/ascorbate treatments followed by Ca2+ addition revealed that Ca2+ uptake inhibition was slower than Ca2+ release. Taken together, data showed that free radicals and, in particular, hydroxyl radicals, affected the scallop SR Ca2+ regulation. This mainly occurred through Ca2+ channel opening, most likely triggered by sulfhydryl oxidation, which eventually led to massive Ca2+ release from SR vesicles. The demonstration of a specific effect of oxyradicals on SR Ca2+ channels is in line with their possible involvement in cell signaling.

Prenatal sexing and sex determination in infants with ambiguous genitalia by polymerase chain reaction.

Sex determination in both fetuses and infants with ambiguous external genitalia usually necessitates time-consuming and costly karyotyping. We propose a simple, rapid, and reliable method of prenatal and postnatal sex determination by means of the PCR, a technique currently used to identify gender for forensic purposes. DNA was extracted from 20 samples of whole blood from infants with ambiguous genitalia and from five samples of amniotic fluid. Three markers were amplified from each specimen: a Y chromosome alphoid repeat sequence and two homologous genes, amelogenin (AME) and zinc finger protein (ZFP). All three were detected in under 10 hr. A comparison of the results obtained with those of cytogenetic analysis of the same samples showed a perfect sex match, demonstrating that this PCR technique provides an accurate means of determining gender.

Type distribution and allele frequencies of three serum proteins in the Asiago Plateau population (northern Italy).

Historical studies on the Asiago Plateau have pointed to the peculiarity of its inhabitants in terms of their socio-cultural development marked by long periods of linguistic and cultural isolation. The present research on some serum protein markers (TF, GC and HP) aims to establish whether this isolation may have caused this population to become different from the others in terms of gene frequencies. For this purpose, transferrin (TF), group-specific component (GC) and human haptoglobin (HP) polymorphisms were studied in 435 subjects. GC and HP were found to be within the range of variation known for the Italian Peninsula.