Radium-223 in the Treatment of Metastatic Castrate-Resistant Prostate Cancer.

Background Radium 223 (Ra-223) has been successfully utilised for the treatment of men with metastatic castrate resistant prostate cancer (mCRPC). To date, no real world outcomes from its use in the Irish population have been described. Methods All men referred to our institution for Ra-223 from September 2016 to March 2019 were included. Patient demographics, treatments received, toxicities and outcomes were recorded. Overall survival (OS) and progression free survival (PFS) were analysed using the Kaplan-Meier method. Results Complete data was available for 54 men. Median age was 75 years (range 61-86 years). The median number of prior systemic treatments for mCRPC was 2 (range 0-4). Median ECOG performance status was 1 at the start of treatment and 2 at completion. The median number of Ra-223 cycles received was 4 with 37%(n=20) completing all 6 planned cycles. The most common treatment-related toxicity was fatigue seen in 52% of patients ( n=28). Improved pain scores were documented in 76% of men requiring opioid analgesia at the start of treatment. The median OS was 7 months. A good ECOG performance status, fewer than 6 bone metastases, normal alkaline phosphatase level at start of treatment and chemotherapy naivety were associated with improved OS. Conclusions Ra-223 is a moderately well tolerated palliative treatment amongst Irish men with mCRPC.

Ancestry and phenotype predictions from touch DNA using massively parallel sequencing.

Direct PCR can be used to successfully generate full STR profiles from DNA present on the surface of objects. STR profiles are only of use in cases where a potential donor profile is available for comparison, and DNA is of sufficient DNA quality and quantity to generate a reliable profile. Often, no donor information is available and only trace DNA is present on items. As a result, alternative techniques are required to generate genetic data that can provide investigative leads. Massively parallel sequencing (MPS) offers the ability to detect trace levels of DNA and improve DNA analysis success from touched items. Here, we present the first application of direct PCR coupled with MPS to generate forensic intelligence SNP data from latent DNA. The panels assessed are (1) the HIrisplex System that targets 24 SNPs to simultaneously predict hair and eye, and (2) the Precision ID Ancestry Panel that targets 165 autosomal SNPs indicative of biogeographic ancestry. For each panel, we analysed 60 touched samples across five individuals and four substrates (glass slide, fuse, zip-lock bag and wire) using Ion AmpliSeq Library Preparation Kit on the automated Ion Chef System and Ion Torrent PGM. We examine the SNP recovery, concordance with reference samples and the genotype reproducibility from different substrates and donors. The results demonstrate the application of this approach for obtaining informative genetic from trace amounts of DNA.

Increased expression and phosphorylation of 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase isoforms in urinary exosomes in pre-eclampsia.

BACKGROUND: Glycolysis is altered in various kidney diseases, but little is known about glycolysis in pre-eclampsia, a multi-system disorder with major pathological effects on the kidney. Urinary exosomes provide a non-invasive alternative for studying changes in kidney metabolism. This study aims to characterise the expression and phosphorylation of isozymes of the key glycolytic regulatory protein, 6-phosphofructokinase-2-kinase/fructose-2,6-bisphosphatase (PFK-2/FBPase-2), in urinary exosomes of subjects with pre-eclampsia (PE), compared to normotensive non-pregnant (NC) and normotensive pregnant (NP) controls. METHODS: A cross-sectional study of NC (n = 19), NP (n = 23) and PE (n = 29) subjects was performed. Exosomes were isolated from urine samples by differential ultracentrifugation, and then analyzed by Western blot and densitometry for expression of PFK-2/FBPase-2 isozymes (PFKFB2, PFKFB3 and PFKFB4) and phosphorylation of PFKFB2 at residues Ser483 and Ser466 and PFKFB3 at Ser461. RESULTS: PFKFB2 expression was increased 4.7-fold in PE compared to NP (p < 0.001). PFKFB2 phosphorylation at Ser483 was increased 2.6-fold in PE compared to NP (p = 0.002). Expression of phosphorylated PFKFB2/PFKFB3 at Ser466/Ser461 was increased in PE, being present in 77.4% (95% CI 59.9-88.9%) of PE and 8.3% (95% CI 1.2-27.0%) of NP samples (p < 0.001). PFKFB3 was more commonly expressed in PE, detected in 90.3% (95% CI 74.3-97.4%) of PE and 8.3% (95% CI 1.2-27.0%) of NP samples (p < 0.001). PFKFB4 had a 7.2-fold increase in expression in PE compared to NP (p < 0.001). No significant differences between NP and NC groups were observed. CONCLUSION: Regulatory proteins that increase glycolysis are increased in the urinary exosomes of subjects with pre-eclampsia, suggesting that renal glycolysis may be increased in this condition.

A Survey of Colorectal Cancer Surveillance Practices In Ireland, And Implementation of A Survivorship Care Plan Pilot Programme

Aims The number of colorectal cancer (CRC) survivors in Ireland is rising. We aimed to survey current surveillance practices and pilot the use of survivorship care plans (SCPs) in the clinic. Methods An online survey was issued to medical oncologists (MOs) in designated cancer centres (DCC) and satellite centres. The SCP was piloted in CRC patients and a follow-up questionnaire assessing their views was issued. Results Responses from 8 DCC and satellite centres were obtained (n=13). Routine surveillance is practiced by 77% (n=10) and 69% (n=9) believe that the MO clinic is inappropriate for follow-up. Most think that the SCP is useful and that ANP-led surveillance clinics should be introduced. Of 16 patients who replied to the survey, most felt that the SCP was bene􀂡cial. Sixty-two percent (n=10) were agreeable to GP follow-up using the SCP. Conclusion Surveillance practices in Ireland are heterogeneous. The SCP may be useful for streamlining follow-up practices nationally.

Vertebrate SLRP family evolution and the subfunctionalization of osteoglycin gene duplicates in teleost fish.

BACKGROUND: Osteoglycin (OGN, a.k.a. mimecan) belongs to cluster III of the small leucine-rich proteoglycans (SLRP) of the extracellular matrix (ECM). In vertebrates OGN is a characteristic ECM protein of bone. In the present study we explore the evolution of SLRP III and OGN in teleosts that have a skeleton adapted to an aquatic environment. RESULTS: The SLRP gene family has been conserved since the separation of chondrichthyes and osteichthyes. Few gene duplicates of the SLRP III family exist even in the teleosts that experienced a specific whole genome duplication. One exception is ogn for which duplicate copies were identified in fish genomes. The ogn promoter sequence and in vitro mesenchymal stem cell (MSC) cultures suggest the duplicate ogn genes acquired divergent functions. In gilthead sea bream (Sparus aurata) ogn1 was up-regulated during osteoblast and myocyte differentiation in vitro, while ogn2 was severely down-regulated during bone-derived MSCs differentiation into adipocytes in vitro. CONCLUSIONS: Overall, the phylogenetic analysis indicates that the SLRP III family in vertebrates has been under conservative evolutionary pressure. The retention of the ogn gene duplicates in teleosts was linked with the acquisition of different functions. The acquisition by OGN of functions other than that of a bone ECM protein occurred early in the vertebrate lineage.

A review of 10 years of scapula injuries sustained by UK military personnel on operations.

BACKGROUND: Scapula fractures are relatively uncommon injuries, mostly occurring due to the effects of high-energy trauma. Rates of scapula fractures are unknown in the military setting. The aim of this study is to analyse the incidence, aetiology, associated injuries, treatment and complications of these fractures occurring in deployed military personnel. METHODS: All UK military personnel returning with upper limb injuries from Afghanistan and Iraq were retrospectively reviewed using the Royal Centre for Defence Medicine database and case notes (2004-2014). RESULTS: Forty-four scapula fractures out of 572 upper limb fractures (7.7%) were sustained over 10 years. Blast and gunshot wounds (GSW) were leading causative factors in 85%. Over half were open fractures (54%), with open blast fractures often having significant bone and soft tissue loss requiring extensive reconstruction. Multiple injuries were noted including lung, head, vascular and nerve injuries. Injury Severity Scores (ISS) were significantly higher than the average upper limb injury without a scapula fracture (p<0.0001). Brachial plexus injuries occurred in 17%. While military personnel with GSW have a favourable chance of nerve recovery, 75% of brachial plexus injuries that are associated with blast have poorer outcomes. Fixation occurred with either glenoid fractures or floating shoulders (10%); these were as a result of high velocity GSW or mounted blast ejections. There were no cases of deep soft tissue infection or osteomyelitis and all scapula fractures united. CONCLUSION: Scapula fractures have a 20 times higher incidence in military personnel compared with the civilian population, occurring predominantly as a result of blast and GSW, and a higher than average ISS. These fractures are often associated with multiple injuries, including brachial plexus injuries, where those sustained from blast have less favourable outcome. High rates of union following fixation and low rates of infection are expected despite significant contamination and soft tissue loss.

Duplication of Dio3 genes in teleost fish and their divergent expression in skin during flatfish metamorphosis.

Deiodinase 3 (Dio3) plays an essential role during early development in vertebrates by controlling tissue thyroid hormone (TH) availability. The Atlantic halibut (Hippoglossus hippoglossus) possesses duplicate dio3 genes (dio3a and dio3b). Expression analysis indicates that dio3b levels change in abocular skin during metamorphosis and this suggests that this enzyme is associated with the divergent development of larval skin to the juvenile phenotype. In larvae exposed to MMI, a chemical that inhibits TH production, expression of dio3b in ocular skin is significantly up-regulated suggesting that THs normally modulate this genes expression during this developmental event. The molecular basis for divergent dio3a and dio3b expression and responsiveness to MMI treatment is explained by the multiple conserved TREs in the proximal promoter region of teleost dio3b and their absence from the promoter of dio3a. We propose that the divergent expression of dio3 in ocular and abocular skin during halibut metamorphosis contributes to the asymmetric pigment development in response to THs.

Thyroid function of steatitis-affected Mozambique tilapia Oreochromis mossambicus from a sub-tropical African reservoir.

Thyroid function and nutritional indicators were measured in obese, steatitis-affected Mozambique tilapia Oreochromis mossambicus from Loskop Reservoir (LR), South Africa. Plasma thyroid hormones (especially T3) and thyroid follicle histomorphology revealed high levels of activity in every aspect of the thyroid cascade measured in fish from LR compared to a reference population of steatitis-free fish. Concurrent measurements of nutritional state including plasma lipids, liver lipid content and hepatocyte size showed that fish from LR had significant energy stores indicative of abundant nutritional intake. There were distinct sex and seasonal differences, with the highest plasma lipids and T3 levels observed in steatitis-affected females during spring and summer. Positive correlations were observed between plasma lipids (especially cholesterol) and T3 concentrations in fish from both populations, indicating a link between lipid metabolism and thyroid function. There was no direct evidence of thyroid disruption, but this cannot be ruled out until further research determines the factors that underlie the homeostatic shift leading to elevated plasma and liver lipids and T3 levels in steatitis-affected tilapia.

Characterization of the peripheral thyroid system of gilthead seabream acclimated to different ambient salinities.

Thyroid hormones are involved in many developmental and physiological processes, including osmoregulation. The regulation of the thyroid system by environmental salinity in the euryhaline gilthead seabream (Sparus aurata) is still poorly characterized. To this end seabreams were exposed to four different environmental salinities (5, 15, 40 and 55ppt) for 14days, and plasma free thyroid hormones (fT3, fT4), outer ring deiodination and Na+/K+-ATPase activities in gills and kidney, as well as other osmoregulatory and metabolic parameters were measured. Low salinity conditions (5ppt) elicited a significant increase in fT3 (29%) and fT4 (184%) plasma concentrations compared to control animals (acclimated to 40ppt, natural salinity conditions in the Bay of Cádiz, Spain), while the amount of pituitary thyroid stimulating hormone subunit ß (tshb) transcript abundance remained unchanged. In addition, plasma fT4 levels were positively correlated to renal and branchial deiodinase type 2 (dio2) mRNA expression. Gill and kidney T4-outer ring deiodination activities correlated positively with dio2 mRNA expression and the highest values were observed in fish acclimated to low salinities (5 and 15ppt). The high salinity (55ppt) exposure caused a significant increase in tshb expression (65%), but deiodinase gene expression (dio1 and dio2) and activity did not change and were similar to controls (40ppt). In conclusion, acclimation to different salinities led to changes in the peripheral regulation of thyroid hormone metabolism in seabream. Therefore, thyroid hormones are involved in the regulation of ion transport and osmoregulatory physiology in this species. The conclusions derived from this study may also allow aquaculturists to modulate thyroid metabolism in seabream by adjusting culture salinity.

Post-Chemotherapy Retroperitoneal Lymph Node Dissection in Patients with Non-Seminomatous Germ Cell Tumour (NSGCT).

Diabetic retinopathy is a significant complication of diabetes, and the most common cause of blindness in people under the age of 65. The National Diabetic Retinal Screening Programme (Diabetic RetinaScreen) was established to detect sight threatening retinopathies. The purpose of this cross-sectional study is to determine the barriers to the uptake of Diabetic RetinaScreen, to investigate discrepancies in attendance, if any, between patients whose diabetes care is delivered in a large tertiary referral hospital out-patient setting or in general practice, and to evaluate general practitioner's satisfaction with the service. Older age (OR 1.023, 95% CI 1.001 to 1.046) and complications of diabetes, excluding ocular complications, (OR 2.741, 95% CI 1.158 to 6.489) were associated with increased attendance at Diabetic RetinaScreen. Online referral is now available and the preferred method of referral. Efforts to encourage younger patients who do not yet have complications of diabetes may be beneficial.

Is there a role for the development of a supra-regional network for the management of penile cancer in the Republic of Ireland?

INTRODUCTION: There is an average of 25 cases of penile cancer in the Republic of Ireland each year. Due to the low volume of cases, the National Institute for Clinical Excellence recommends that treatment is centralised to allow the best standardised treatment for primary tumours and nodal disease. OBJECTIVES: To determine whether outcomes for patients with penile cancer differed significantly between secondary and tertiary referral centres in the Republic of Ireland. METHODS: Between 2001 and 2014, 36 patients were treated in the Mercy University Hospital (MUH) with penile cancer. Twenty patients were treated primarily in MUH and 16 patients underwent initial management in a secondary referral centre (SRC) with subsequent referral to the MUH. A retrospective matched case-control study was performed on this patient cohort. RESULTS: There were no significant differences in length of follow-up or risk factors for the development of penile cancer between both groups (p = 0.6 and p = 0.5 respectively) Ultimately, the incidence of high risk disease, nodal metasases, high grade disease and pelvic lymph node dissection were significantly greater in patients that were initially managed in a SRC (p = 0.02, p = 0.03, p = 0.004 and p = 0.028 respectively). Patients undergoing initial treatment in a SRC had a non-significantly reduced rate of cancer specific survival (88 Vs 66%, MUH Vs SRCs, p = 0.495) and recurrence free survival (85 Vs 46%, MUH Vs SRCs, p = 0.24). CONCLUSION: Our findings suggest that managing penile cancer in special interest centres may improve oncological outcome.

Assessing the alignment of sexual and natural selection using radiomutagenized seed beetles.

A major unsolved question in evolutionary biology concerns the relationship between natural and sexual selection. Sexual selection might augment natural selection, for example if mutations that harm female fecundity also reduce male mating success. Conversely, sexual selection might favour traits that impair naturally selected fitness components. We induced detrimental mutations in Callosobruchus maculatus beetles using X-ray irradiation and then experimentally measured the effect of precopulatory sexual selection on offspring number and survival rate. Sexual selection treatment had a negative effect on egg-to-adult survivorship, although the number of progeny reaching adulthood was unaffected, perhaps because eggs and juveniles that failed to develop lessened competition on the survivors. We hypothesize that the negative effect of sexual selection arose because sexually competitive males transmitted a smaller nuptial gift or carried alleles that conferred reduced survival. Although we found no evidence that sexual selection on males can purge alleles that are detrimental to naturally selected fitness components, such benefits might exist in other environmental or genetic contexts.

Radiation exposure from diagnostic imaging in young patients with testicular cancer.

OBJECTIVES: Risks associated with high cumulative effective dose (CED) from radiation are greater when imaging is performed on younger patients. Testicular cancer affects young patients and has a good prognosis. Regular imaging is standard for follow-up. This study quantifies CED from diagnostic imaging in these patients. METHODS: Radiological imaging of patients aged 18-39 years, diagnosed with testicular cancer between 2001 and 2011 in two tertiary care centres was examined. Age at diagnosis, cancer type, dose-length product (DLP), imaging type, and frequency were recorded. CED was calculated from DLP using conversion factors. Statistical analysis was performed with SPSS. RESULTS: In total, 120 patients with a mean age of 30.7 ± 5.2 years at diagnosis had 1,410 radiological investigations. Median (IQR) surveillance was 4.37 years (2.0-5.5). Median (IQR) CED was 125.1 mSv (81.3-177.5). Computed tomography accounted for 65.3 % of imaging studies and 98.3 % of CED. We found that 77.5 % (93/120) of patients received high CED (>75 mSv). Surveillance time was associated with high CED (OR 2.1, CI 1.5-2.8). CONCLUSIONS: Survivors of testicular cancer frequently receive high CED from diagnostic imaging, mainly CT. Dose management software for accurate real-time monitoring of CED and low-dose CT protocols with maintained image quality should be used by specialist centres for surveillance imaging. KEY POINTS: • CT accounted for 98.3 % of CED in patients with testicular cancer. • Median CED in patients with testicular cancer was 125.1 mSv • High CED (>75 mSv) was observed in 77.5 % (93/120) of patients. • Dose tracking and development of low-dose CT protocols are recommended.

Orchestrating change: The thyroid hormones and GI-tract development in flatfish metamorphosis.

Metamorphosis in flatfish (Pleuronectiformes) is a late post-embryonic developmental event that prepares the organism for the larval-to-juvenile transition. Thyroid hormones (THs) play a central role in flatfish metamorphosis and the basic elements that constitute the thyroid axis in vertebrates are all present at this stage. The advantage of using flatfish to study the larval-to-juvenile transition is the profound change in external morphology that accompanies metamorphosis making it easy to track progression to climax. This important lifecycle transition is underpinned by molecular, cellular, structural and functional modifications of organs and tissues that prepare larvae for a successful transition to the adult habitat and lifestyle. Understanding the role of THs in the maturation of organs and tissues with diverse functions during metamorphosis is a major challenge. The change in diet that accompanies the transition from a pelagic larvae to a benthic juvenile in flatfish is associated with structural and functional modifications in the gastrointestinal tract (GI-tract). The present review will focus on the maturation of the GI-tract during metamorphosis giving particular attention to organogenesis of the stomach a TH triggered event. Gene transcripts and biological processes that are associated with GI-tract maturation during Atlantic halibut metamorphosis are identified. Gene ontology analysis reveals core biological functions and putative TH-responsive genes that underpin TH-driven metamorphosis of the GI-tract in Atlantic halibut. Deciphering the specific role remains a challenge. Recent advances in characterizing the molecular, structural and functional modifications that accompany the appearance of a functional stomach in Atlantic halibut are considered and future research challenges identified.

Penile cancer--Guideline adherence produces optimum results.

OBJECTIVE: To audit the management and outcome of penile cancer in a tertiary university teaching hospital, comparing our results to international best practice and published guidelines. METHODS: The Hospital Inpatient Enquiry database of the Mercy University Hospital was interrogated for penile cancer patients treated between 2001 and 2012. Data relating to presentation, local treatment, histology, lymph-node management, outcome and survival was recorded. Data were analysed using the Log Rank test, with significance defined as P ≤ 0.05. RESULTS: Twenty-five patients were identified with a median age of 61 years. The majority of cases at presentation were ≥ T2 (54%) and intermediate to high grade (76%). The median follow-up of patients was 3.75 years (range 9 months-10 years). Overall survival was 76% (n = 19), these patients are all disease free to date. Disease-specific survival was 85% at 10 years. Penile cancer related mortality was 8% (n = 2), 4 patients (16%) died of non-penile cancer related causes. Twenty-two patients (88%) had surgery and 3 patients (12%) had radiotherapy. Based on EAU guidelines inguinal lymph node dissection (ILND) was performed in 64% (n = 16) of cases with 44% (n = 7) of these patients requiring concurrent bilateral pelvic lymph node dissection. Fifty percent (n = 8) of ILNDs showed metastatic disease. Ten year disease-specific survival for node negative versus node positive disease is 100% versus 57%. Thirty-two percent (n = 8) of patients received chemotherapy. CONCLUSIONS: Penile cancer is a rare oncological condition that often requires bilateral inguinal ± pelvic lymph node dissection and should be managed according to published guidelines, in specialist centres in order to maximize outcomes.

Polyandrous females found fitter populations.

Multiple mating by females (polyandry) requires an evolutionary explanation, because it carries fitness costs in many species. When mated females disperse alone to a new habitat, their offspring may have no option but to mate with their siblings and incur inbreeding depression. However, some of the offspring of polyandrous females may only be half siblings, reducing inbreeding depression when isolated groups of siblings only have each other as mates. We investigated this putative benefit of polyandry over monandry by initiating multiple genetically isolated populations of Callosobruchus maculatus beetles, each founded by a single female, who received a complete ejaculate from either one or two males. The early generations had comparable fitness, but the F4 and F5 descendants of doubly inseminated females were more numerous and had higher egg-to-adult survival than the descendants of singly inseminated females. This fitness benefit was of similar magnitude whether beetles were reared on their standard food plant, or on a less favourable food source. Our results suggest that polyandrous females produce fitter descendants in inbred founder populations and therefore that polyandry may affect movement ecology and invasion biology.

Characteristics of modern Gleason 9/10 prostate adenocarcinoma: a single tertiary centre experience within the Republic of Ireland.

INTRODUCTION: The 2005 international society of urological pathology consensus statement on Gleason grading in prostate cancer revised Gleason scoring in clinical practice. The potential for grade migration with this refinement poses difficulties in interpreting historical series. We report the characteristics of a recent cohort of consecutive Gleason score 9 or 10 prostate cancers in our institution. The purpose of this study was to define the clinicopathologic variables and staging information for this high-risk population, and to identify whether traditional prostate staging techniques are adequate for this subcohort of men. MATERIALS AND METHODS: A computational review of our pathology database was performed. Between May 2010 and September 2012, 1,295 consecutive biopsies were undertaken, 168 of which were high-grade tumours (12.97 %). This group were divided into two cohorts of which 84 (12.05 %) had a highest reported Gleason score of 9 (N = 79) or 10 (N = 5) and 84 were reported as Gleason 8. All biopsies were double-reported by pathologists with a special interest in uropathology. RESULTS: Men diagnosed with a Gleason pattern 5 tumour were statistically far more likely to have advanced disease on direct rectal examination of the prostate compared with Gleason sum 8 tumours (p < 0.001) and a positive first-degree family history of prostate cancer (p < 0.001). Overall, Gleason sum 9/10 prostate cancers were also found to be statistically more aggressive than Gleason sum 8 tumours on TRUS core biopsy analysis with significantly higher levels of perineural invasion (p < 0.0001) and extracapsular extension (p = 0.001) as well as a higher levels of tumour found within the core biopsy sample. Those men diagnosed with Gleason pattern 5 prostate cancer also had radiological indicators of increased tumour aggressiveness compared with Gleason sum 8 cancer with respect to bone (p = 0.0002) and visceral (p = 0.044) metastases at presentation. CONCLUSIONS: This series of Gleason score 9/10 prostate cancers serves to highlight the large disease burden, adverse pathologic features, and locally advanced nature of this aggressive subtype, which has previously been under-described in the literature, and differs from historical series in having a large high-grade cohort demonstrating high rates of metastatic disease. A history of prostate cancer amongst first-degree relatives was particularly prevalent in this population raising the issue of screening in a high-risk population. The high incidence of visceral metastatic disease at presentation supports upfront staging with CT thorax, abdomen, and pelvis in patients with Gleason 9 or 10 prostate cancers.

Sample richness and genetic diversity as drivers of chimera formation in nSSU metagenetic analyses.

Eukaryotic diversity in environmental samples is often assessed via PCR-based amplification of nSSU genes. However, estimates of diversity derived from pyrosequencing environmental data sets are often inflated, mainly because of the formation of chimeric sequences during PCR amplification. Chimeras are hybrid products composed of distinct parental sequences that can lead to the misinterpretation of diversity estimates. We have analyzed the effect of sample richness, evenness and phylogenetic diversity on the formation of chimeras using a nSSU data set derived from 454 Roche pyrosequencing of replicated, large control pools of closely and distantly related nematode mock communities, of known intragenomic identity and richness. To further investigate how chimeric molecules are formed, the nSSU gene secondary structure was analyzed in several individuals. For the first time in eukaryotes, chimera formation proved to be higher in both richer and more genetically diverse samples, thus providing a novel perspective of chimera formation in pyrosequenced environmental data sets. Findings contribute to a better understanding of the nature and mechanisms involved in chimera formation during PCR amplification of environmentally derived DNA. Moreover, given the similarities between biodiversity analyses using amplicon sequencing and those used to assess genomic variation, our findings have potential broad application for identifying genetic variation in homologous loci or multigene families in general.