Stored DNA Research Articles

Escalating-dose HLA-mismatched DLI is safe for the treatment of leukaemia relapse following alemtuzumab-based myeloablative allo-SCT

Although the feasibility of using HLA-mismatched unrelated donors as an alternate graft source for haematopoietic SCT (HSCT) has been shown, little is known about the safety of HLA-mismatched DLI for the treatment of relapse. We examined the outcome of 58 consecutive leukaemia patients who received escalating-dose DLI for treatment of relapse after alemtuzumab-conditioned myeloablative unrelated donor HSCT at our institution. High-resolution HLA typing on stored DNA samples revealed mismatches in 28/58 patients who were considered HLA-matched at the time of transplantation. Following DLI from HLA-matched (10/10) (n=30) or -mismatched (7-9/10) (n=28) unrelated donors, we found no significant difference in the incidence of acute GVHD (17.2% versus 23.1%, P=0.59), probability of remission at 3 years (62.1% versus 63.9%, P=0.89) or 5-year OS (89.8% versus 77.7%, P=0.22). We conclude that escalating-dose DLI can be safely given to HLA-mismatched recipients following T-depleted myeloablative HSCT.

Questing Dermacentor reticulatus harbouring Babesia canis DNA associated with outbreaks of canine babesiosis in the Swiss Midlands

In 2011 and 2012, outbreaks of clinical canine babesiosis were observed in 2 areas of the Swiss Midlands that had no history of this disease so far. In one area, cases of canine babesiosis occurred over 2 consecutive tick seasons. The outbreaks involved 29 dogs, 4 of which died. All dogs were infected with large Babesia sp. as diagnosed in Giemsa-stained blood smears and/or PCR. These were identified as B. canis (formerly known as B. canis canis) by subsequent partial sequencing of the 18S rRNA gene of Babesia sp. Interestingly, the sequence indicated either a genotype with heterogeneity in the ssrRNA gene copies or double infection with different B. canis isolates. None of the dogs had a recent travel history, but one had frequently travelled to Hungary and had suffered twice from clinical babesiosis 18 and 24 months prior to the outbreak in autumn 2011. Retrospective sequencing of a stored blood DNA sample of this dog revealed B. canis, with an identical sequence to the Babesia involved in the outbreaks.For the first time in Switzerland, the partial 18S rRNA gene of B. canis could be amplified from DNA isolated from 19 out of 23 adult Dermacentor reticulatus ticks flagged in the same area. The sequence was identical to that found in the dogs. Furthermore, one affected dog carried a female D. reticulatus tick harbouring B. canis DNA. Our findings illustrate that, under favourable biogeographic and climatic conditions, the life-cycle of B. canis can relatively rapidly establish itself in previously non-endemic areas. Canine babesiosis should therefore always be a differential diagnosis when dogs with typical clinical signs are presented, regardless of known endemic areas.

Natural History, a Master Class

​ManyMany people think we're entering a golden age of genomics, with technological breakthroughs yielding an explosion of data along with unprecedented insights into the genes and molecules that underlie life. Personally, I find it all a bit dull and uninspiring. Perhaps this cynicism stems from a conversation I once had with a fanatical, eye-popping cladist who proudly told me, “We don't need to save those tropical forests, we've already got samples of most of their DNA in the museums!” This perspective is slowly giving rise to the significantly deranged belief that we don't need to worry about the loss of biodiversity: we'll simply recreate it from stored DNA. The current cult of genomics and its ominous trickle-down effects on high-school biology teaching means it's sometimes easy to lose sight of the biology that surrounds us. Even so, there's something about the natural world and its creatures that still sparks a deep fascination and likely inspired many of us to study biology in the first place. Field Notes on Science and Nature reminds us why we find nature so appealing and just how much fun getting into the field can be.

Child Abuse and Epigenetic Mechanisms of Disease Risk

Child abuse is highly prevalent and associated with increased risk for a range of health problems, including cancer, cardiovascular disease, diabetes, psychiatric disorders, and other health problems. Little is currently known about the mechanism by which early adversity confers risk for health problems later in life. To determine if there are epigenetic differences associated with child maltreatment that may help explain association between adverse childhood experiences and later health problems. As part of a study examining genetic and environmental factors associated with depression, saliva DNA specimens were collected on 96 maltreated children removed from their parents due to abuse or neglect and 96 demographically matched control children between 2003 and 2010. In 2011, the Illumina 450K BeadChip was used on stored DNA specimens and analyzed to examine whole-genome methylation differences between maltreated and control children. After controlling for multiple comparisons, maltreated and control children had significantly different methylation values at 2868 CpG sites (p<5.0 × 10(-7), all sites; average methylation difference per site=17%; range=1%-62%). The gene set contained numerous markers of diseases and biological processes related to the health problems associated with early childhood adversity. Although replication is required, this study suggests that epigenetic mechanisms may be associated with risk for health problems later in life in maltreated children. This study lays the groundwork for future studies examining health and methylation measures to further characterize the role of epigenetic mechanisms in conferring risk for medical problems in individuals with histories of early adversity.

Abstract IA03: New assays, old specimens: Telomere length and activity.

Abstract Telomeres are chromatin structures that cap chromosome ends and protect the genetic integrity of cells. They progressively shorten with every cell division, and cells will generally undergo apoptosis or senescence after their telomeres reach a critically short length. If these pathways are bypassed, cells can continue replicating with concomitant telomere shortening, resulting in crisis, in which there is rampant chromosomal instability and cell death. However, a very few cells may survive crisis, and become immortalized by activation of a telomere maintenance mechanism (usually, telomerase activation). This subset of cells with genomic instability and telomere maintenance could progress towards malignant transformation1. Telomere length is influenced by genetic, epigenetic, and environmental factors. Shorter telomere length is associated with increasing age, exposure to cigarette smoke, oxidative stress and male gender, and varies by genetic ancestry. After accounting for these factors, telomere length is still highly variable among individuals. Different chromosomes and chromosome arms of the same chromosome have varying telomere length. Telomere length also varies considerably between organ sites, likely due to the difference in cellular turnover rates. Global telomere length can be measured using a variety of assays, including: southern blotting, which requires a large amount of DNA and is considered to be the “gold standard”; quantitative fluorescence in situ hybridization (qFISH), which is used to assay cells from fresh blood or tissue but can also be used to assay paraffin-embedded samples when combined with immunofluorescence to identify specific cell types; and real-time quantitative PCR (qPCR), which is higher throughput and can be applied to stored DNA samples. The qPCR methods tend to suffer from high coefficients of variation, and several different approaches have been developed to address this limitation. Both qFISH and qPCR methods can be modified to measure chromosome arm-specific telomere length2. Shortened telomere length (for the most part, measured in peripheral blood) has been reported to be associated with increased risk of several cancer types. These associations are generally stronger in case-control studies than in prospective studies. Also, a growing number of publications are reporting that longer telomere length is associated with increased risk of cancer3. Questions remain about whether associations with telomere length can be explained by other factors. While telomerase is expressed in over 90% of cancers and in some precursor lesions, its expression is weak or undetectable in most normal cells other than germ cells, stem cells and activated T cells and monocytes. To date, it is unclear whether or not peripheral lymphocyte telomerase activity is associated with increased cancer risk. Nonetheless, multiple genetic variants in the TERT locus (which encodes telomerase) are clearly associated with a number of different cancer types. In summary, several lines of evidence support the possibility that telomere length and telomerase activity may be causally associated with risk of some types of cancer, but additional prospective studies are needed, with careful attention to the assays used. Citation Format: Jennifer Anne Doherty. New assays, old specimens: Telomere length and activity. [abstract]. In: Proceedings of the AACR Special Conference on Post-GWAS Horizons in Molecular Epidemiology: Digging Deeper into the Environment; 2012 Nov 11-14; Hollywood, FL. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2012;21(11 Suppl):Abstract nr IA03.

Association of Shorter Leukocyte Telomere Repeat Length With Dementia and Mortality

Shortening of chromosomal telomeres is a consequence of cell division and is a biological factor related to cellular aging and potentially to more rapid organismal biological aging. To determine whether shorter telomere length (TL), as measured in human blood samples, is associated with the development of Alzheimer disease and mortality. We studied available stored leukocyte DNA from a community-based study of aging using realtime polymerase chain reaction analysis to determine mean TL in our modification of a method measuring the ratio of telomere sequence to single-copy gene sequence. A multiethnic community-based study of aging and dementia. One thousand nine hundred eighty-three subjects 65 years or older. Mean (SD) age at blood draw was 78.3 (6.9) years; at death, 86.0 (7.4) years. Median follow-up for mortality was 9.3 years; 190 (9.6%) developed incident dementia. The TL was inversely related to age and shorter in men than women. Persons dying during follow-up had a shorter TL compared with survivors (mean [SD], 6218 [819] vs 6491 [881] base pairs [bp] [P.001]), even after adjustment for age, sex, education, and apolipoprotein E genotype. Individuals who developed dementia had significantly shorter TL (mean [SD], 6131 [798] bp for prevalent cases and 6315 [817] bp for incident cases) compared with those remaining dementia-free (6431 [864] bp). Cox-regression analyses showed that shorter TL was a risk for earlier onset of dementia (P=.05), but stratified analyses for sex showed that this association of age at onset of dementia with shorter TL was significant in women only. Our findings suggest that shortened leukocyte TL is associated with risks for dementia and mortality and may therefore be a marker of biological aging.

A Comparison of Two Methods of Eluting Insect Dna from Flinders Technology Associates Cards

Flinders Technology Associates (FTATM) cards contain chemicals that lyse cells and protect DNA from degradation for room-temperature storage (WhatmanTM, 2009). Consequently, DNA extrac tion takes less time and storage requires less en ergy and space than traditional methods requir ing lysis, purification, and -20 °C storage in tubes. These cards are also easy to transport and face fewer shipping restrictions and less opportunity for damage than mounted specimens or those stored in alcohol. DNA stored on FTATM cards pro duces a full allele compliment during genotyping after 11 yr (Kline, 2010) and the manufacturer re ports successful PCR with FTATM stored DNA for 17 yr and counting (WhatmanTM, 2009). Despite these benefits, this technology has been utilized infrequently with insects and other arthropods (Miller et al. 2012). Desloire et al. (2006) report ed mixed results obtaining successful PCR from mite DNA and Bujang et al. (2011) were unable to obtain successful PCR reactions from termite DNA when using the manufacturer's protocol. This lead to the development of an alternative method of preparing an FTATMarchived sample for successful PCR (Bujang et al. 2011). There may be several hurdles impeding broader use of the FTATM technology by arthropod research ers. First, the DNA quality and quantity of the washed, single-use, FTATM disc is untestable leading to uncertainty about the cause when PCR fails and second, the wash reagents are relatively expensive ($0.23-$0.36 for two 200uL FTATM puri fication reagent washes). Initial attempts to PCR amplify FTATM archived whitefly DNA using the manufacturer's protocol and the methods of Bu jang et al. (2011) yielded mixed results but PCR was successful when discs were boiled for 5 min in

Direct PCR by the AmpF lSTR NGM™ kit for database purpose

To fully maximize the utility of DNA databases for tracing the origins of criminal activity, the streamlining of database sample processing must also be accompanied by high performance chemistries. Blood and buccal samples are often used for convicted-felon DNA profile databases, as these samples are easy to obtain. The AmpF lSTR NGM™ (Next Generation Multiplex) kit provides enhanced performance on degraded and inhibited samples and tolerance to PCR inhibitors, so we tested the kit ability to amplify directly blood and buccal samples deposited on special collecting cards. The ability to amplify stored DNA directly would allow the lab to get results more efficiently by eliminating the DNA purification step, minimizing the possibility of contamination reducing costs and time accelerating testing by as much as 30% so that lab faster would send consistent results to national database.

Drug resistance prevalence and HIV-1 variant characterization in the naive and pretreated HIV-1-infected paediatric population in Madrid, Spain

Drug resistance mutations affect antiretroviral therapy (ART) effectiveness in HIV-1-infected children, compromising long-term therapy. HIV-1 variants and drug resistance mutations were identified in HIV-infected children from Madrid, Spain. Patients from the Madrid cohort of HIV-infected children (1993-2009) with available pol sequences or infected samples stored at the Spanish HIV-1 BioBank were selected. Specimens were used to perform new pol sequences when not available. HIV-1 variants were characterized by phylogenetic analysis. Resistance mutations were identified according to the International AIDS Society-USA list (2009). In 198 patients, pol sequences were recovered from routine resistance testing (n = 98) or newly performed using stored plasma, lymphocytes or DNA (n = 100). Patients were mostly Europeans (90%), with moderate to severe AIDS symptoms (65%), on ART (85%) when the specimen was sequenced and infected by subtype B (90%). Among the 19 HIV-1 non-B variants found, 58% were recombinants (8CRF02_AG, 1CRF08_BC, 1CRF12_BF and 1CRF13_cpx) and the rest were 'pure' non-B subtypes (1A2, 2C, 2D, 1F1, 1G and 1H). Transmitted drug resistance (TDR) mutations were detected in 13% of naive children; 4%, 7% and 10% for protease inhibitors (PIs), nucleoside reverse transcriptase inhibitors (NRTIs) and non-nucleoside reverse transcriptase inhibitors (NNRTIs), respectively. Global resistance prevalence was higher (66%) among ART-exposed children; 37% for PIs, 54% for NRTIs and 35% for NNRTIs. HIV-1 non-B variants infected 10% of the cohort during 1993-2009. Resistant viruses were present in 26.5% and 66% of naive and pretreated children, respectively. Our data suggest that TDR prevalence in children could be higher than that reported in adults in Spain. The provided data will help to improve clinical management of HIV-infected children in Spain.

Simplified Field Preservation of Tissues for Subsequent DNA Analyses*

Successful DNA-based identification of mass disaster victims depends on acquiring tissues that are not highly degraded. In this study, multiple protocols for field preservation of tissues for later DNA analysis were tested. Skin and muscle samples were collected from decaying pig carcasses. Tissues were preserved using cold storage, desiccation, or room temperature storage in preservative solutions for up to 6 months. DNA quality was assessed through amplification of successively larger segments of nuclear DNA. Solution-based storage, including a DMSO/NaCl/EDTA mixture, alcohols, and RNAlater preserved DNA of the highest quality, refrigeration was intermediate, and desiccation was least effective. Tissue type and extent of decomposition significantly affected stored DNA quality. Overall, the results indicate that any tissue preservation attempt is far superior to delaying or forgoing preservation efforts, and that simple, inexpensive methods can be highly effective in preserving DNA, thus should be initiated as quickly as possible.

Assessing a novel room temperature DNA storage medium for forensic biological samples

The ability to properly collect, analyze and preserve biological stains is important to preserving the integrity of forensic evidence. Stabilization of intact biological evidence in cells and the DNA extracts from them is particularly important since testing is generally not performed immediately following collection. Furthermore, retesting of stored DNA samples may be needed in casework for replicate testing, confirmation of results, and to accommodate future testing with new technologies. A novel room temperature DNA storage medium, SampleMatrix™ (SM; Biomatrica, Inc., San Diego, CA), was evaluated for stabilizing and protecting samples. Human genomic DNA samples at varying amounts (0.0625–200 ng) were stored dry in SM for 1 day to 1 year under varying conditions that included a typical ambient laboratory environment and also through successive freeze–thaw cycles (3 cycles). In addition, spiking of 1–4× SM into samples prior to analysis was performed to determine any inhibitory effects of SM. Quantification of recovered DNA following storage was determined by quantitative PCR or by agarose gel electrophoresis, and evaluation of quantitative peak height results from multiplex short tandem repeat (STR) analyses were performed to assess the efficacy of SM for preserving DNA. Results indicate no substantial differences between the quality of samples stored frozen in liquid and those samples maintained dry at ambient temperatures protected in SM. For long-term storage and the storage of low concentration samples, SM provided a significant advantage over freezer storage through higher DNA recovery. No detectable inhibition of amplification was observed at the recommended SM concentration and complete profiles were obtained from genomic DNA samples even in the presence of higher than recommended concentrations of the SM storage medium. The ability to stabilize and protect DNA from degradation at ambient temperatures for extended time periods could have tremendous impact in simplifying and improving sample storage conditions and requirements. The current work focuses on forensics analysis; however this technology is applicable to all endeavors requiring storage of DNA.

PTCH promoter methylation at low level in sporadic basal cell carcinoma analysed by three different approaches

Basal cell carcinoma (BCC) is the most common form of skin cancer. Mutations of the PTCH hallmark gene are detected in about 50-60% of BCCs, which raises the question whether other mechanisms such as promoter methylation can inactivate PTCH. Therefore, we performed methylation analysis of the PTCH promoter in a total of 56 BCCs. The sensitivity of three different methods, including direct bisulphite sequencing PCR, MethyLight and high-resolution melting (HRM), was applied and compared. We found that HRM analysis of DNA from fresh tissue [rather than formalin-fixed and paraffin-embedded tissue (FFPE)] was the most sensitive method to detect methylation. Low-level methylation of the PTCH promoter was detected in five out of 16 analysed BCCs (31%) on DNA from fresh tissue but only in two (13%) samples on short-time stored FFPE DNA from the very same tumors. In contrast, we were unable to detect methylation by HRM on long-time stored DNA in any of the remaining 40 BCC samples. Our data suggest that (i) HRM on DNA extracted from fresh tissue is the most sensitive method to detect methylation and (ii) methylation of the PTCH promoter may only play a minor role in BCC carcinogenesis.

Mycoplasma genitalium PCR: Does Freezing of Specimens Affect Sensitivity?

Mycoplasma genitalium is an established cause of sexually transmitted infections. Studies of disease associations are often performed on archived specimens, but little is known about the effect of storage of specimens on the detection of M. genitalium. Genital swab and first-void urine specimens submitted for detection of M. genitalium were tested on the day of receipt. Remnants of positive original specimens as well as DNA preparations were stored at -20°C for up to 18 months. A total of 361 M. genitalium-positive specimens were available. PCR after repeat DNA preparation was performed for 262 specimens. The sensitivity after repeat DNA preparation was 90%, and the median decrease in DNA load was 155 genome equivalents (geq) (P < 0.0001). For 327 specimens, PCR could be repeated on the primary DNA preparation. The sensitivity of PCR after storage was 95%, and the median decrease in DNA load was 13.5 geq (P < 0.0001). The specimens yielding negative results at repeat testing had a significantly lower median DNA load in the primary analysis than those with a repeat positive test (P < 0.0001). For 228 specimens, PCR could be performed both on the primary DNA preparation and after repeat DNA preparation. The median DNA load was lower after repeat DNA extraction than after repeat testing of the stored DNA extract (P < 0.0001). In conclusion, the M. genitalium DNA load as well as the detection rate decreased after storage. This was more pronounced in clinical specimens stored frozen than in stored DNA extracts, particularly in those with an initial low DNA load.

CCAAT/enhancer binding protein α, β and δ gene variants: associations with obesity related phenotypes in the Leeds Family Study

To identify novel polymorphisms in the genes encoding the transcription factors CCAAT/enhancer binding protein alpha, beta and delta ( CEBPA, CEBPB, CEBPD) and investigate associations between polymorphisms and obesity-related phenotypes. Denaturing high-performance liquid chromatography (HPLC) was used to screen for novel gene variants and polymorphisms were genotyped in stored DNA from participants of the Leeds Family Study (537 subjects from 89 families). Genotype and haplotype analyses were carried out in STATA and PBAT, respectively. Twenty-five polymorphisms were identified; 11 in CEBPA, 12 in CEBPB and 2 in CEBPD. Several allelic variants were associated at a nominal 5% level with waist-to-hip ratio (-919G>A in CEBPA, -412G>T and 646C>T in CEBPB), leptin (1558G>A in CEBPA, -1051A>G and 1383T>- in CEBPB) and adiponectin (1382G>T and 1903G>T in CEBPB). Effects of CEBPA and CEBPB allelic variants were independent, but variants within each gene were in linkage disequilibrium. Several associations were observed between other obesity-related traits and allelic variants in CEBPA and CEBPB, but not CEBPD. These findings suggest that common allelic variants in CEBPA and CEBPB could influence abdominal obesity and related metabolic abnormalities associated with type 2 diabetes and cardiovascular disease in healthy White Northern European families, although results require independent confirmation.

One Hundred Twenty-One Dystrophin Point Mutations Detected from Stored DNA Samples by Combinatorial Denaturing High-Performance Liquid Chromatography

Duchenne and Becker muscular dystrophies are caused by a large number of different mutations in the dystrophin gene. Outside of the deletion/duplication "hot spots," small mutations occur at unpredictable positions. These account for about 15 to 20% of cases, with the major group being premature stop codons. When the affected male is deceased, carrier testing for family members and prenatal diagnosis become difficult and expensive. We tailored a cost-effective and reliable strategy to discover point mutations from stored DNA samples in the absence of a muscle biopsy. Samples were amplified in combinatorial pools and tested by denaturing high-performance liquid chromatography analysis. An anomalous elution profile belonging to two different pools univocally addressed the allelic variation to an unambiguous sample. Mutations were then detected by sequencing. We identified 121 mutations of 99 different types. Fifty-six patients show stop codons that represent the 46.3% of all cases. Three non-obvious single amino acid mutations were considered as causative. Our data support combinatorial denaturing high-performance liquid chromatography analysis as a clear-cut strategy for time and cost-effective identification of small mutations when only DNA is available.

Risk factors for inhibitor formation in haemophilia: a prevalent case–control study

Inhibitor formation is a major complication of haemophilia treatment. In a prevalent case-control study, we evaluated blood product exposure, genotype and HLA type on haemophilia A inhibitor formation. Product exposure was extracted from medical records. Genotype was determined on stored DNA samples by detection of virtually all mutations-SSCP (DOVAM-S) and subcycling PCR. HLA typing was performed by PCR amplification and exonuclease-released fluorescence. Cases experienced higher intensity factor, 455 vs. 200 U per exposure, P < 0.005, more frequent central nervous system (CNS) bleeding, seven of 20 (35.0%) vs. one of 57 (1.7%), P = 0.001 and more commonly from inhibitor families, seven of 20 (35.0%) vs. zero of 57 (0%), P < 0.001, and African-American, 12 of 63 (19.0%) vs. six of 117 (5.1%), P = 0.015. Among the latter, CNS bleeding was more commonly the initial bleed, 60% vs. 0%, P < 0.001, and survival was shorter, 14 vs. 38 yr, P = 0.025. Inhibitor formation was uncommon in those with missense mutations, two of 65 (3.1%) vs. 31 of 119 (26.0%), P = 0.008, and unrelated to factor VIII immunogenic epitope, P = 0.388, or HLA type, P > 0.100. Genotype was not associated with race. Time to immune tolerance was shorter for titres <120 vs. > or = 120 BU/mL, six vs. 16 months, P < 0.01, but unaffected by tolerizing dose regimen, P > 0.50. Inhibitor formation is associated with high intensity product exposure, CNS bleeding, African-American race and low frequency of missense mutations. The ideal time to initiate prophylaxis to reduce CNS bleeding and inhibitor formation will require prospective studies.

JAK2V617F mutational status and allele burden have little influence on clinical phenotype and prognosis in patients with post-polycythemia vera and post-essential thrombocythemia myelofibrosis

JAK2V617F mutational status and allele burden have little influence on clinical phenotype and prognosis in patients with post-polycythemia vera and post-essential thrombocythemia myelofibrosis

The retention of forensic DNA samples: a socio-ethical evaluation of current practices in the EU

Since the mid-1990s most EU Member States have established a national forensic DNA database. These mass repositories of DNA profiles enable the police to identify DNA stains which are found...

Associations of the β-fibrinogen Hae III and factor XIII Val34Leu gene variants with venous thrombosis

Introduction The factor XIII Val34Leu (100 G → T) and β-fibrinogen Hae III (− 455 G → A) gene variants have been associated with reduced risk of venous thrombosis, but not in all studies. Methods We investigated the associations of these polymorphisms with risk of venous thrombosis in a prospective, population-based study of 21,680 men and women aged 45–100 years at enrollment. Factor XIII 100 G/T and β-fibrinogen − 455 G/A were analyzed on stored DNA from 511 thrombosis cases and 1028 control subjects without thrombosis during follow up. Results The β-fibrinogen A allele was present in 24.4% of cases and 32.3% of controls. Compared to GG subjects, the age, race, and sex adjusted odds ratio (OR) of venous thrombosis was 0.77 (95% CI 0.59–0.99) for GA subjects, and 0.60 (95% CI 0.31–1.16) for AA subjects. The adjusted OR of thrombosis associated with factor XIII 100 G/T was 1.01 (95% CI 0.81–1.26) for GT subjects and 0.45 (95% CI 0.44–1.19) for TT subjects, compared to GG. For both genotypes, ORs of thrombosis were similar in whites and non-whites, although there were no non-white fibrinogen AA cases. β-fibrinogen − 455 GA or AA attenuated the thrombosis risk associated with obesity (from 2.14 to 1.25) and factor V Leiden (from 3.89 to 2.36). Conclusions β-fibrinogen − 455 G/A, but not factor XIII 100 G/T, was associated with a lower risk of venous thrombosis in this general population sample. β-fibrinogen − 455 A may attenuate the increased thrombosis risk associated with obesity or factor V Leiden.

DNA‐based identification of preys from non‐destructive, total DNA extractions of predators using arthropod universal primers

AbstractHere, I show that prey sequences can be detected from DNA of tiger beetles of the genus Rivacindela using whole specimens, nondestructive methods, and universal cytochrome b primers for arthropods. BLAST searches of the obtained sequences against public databases revealed that the diet of Rivacindela is mostly composed of flies but also termites and other beetles. Accurate determination of order, family and even genus was achieved in most cases but rarely to species level. Results suggest that stored DNA samples extracted from whole predatory specimens could be an alternative to dissected gut contents as starting source for DNA‐based dietary studies.