Cardiovascular disease (CVD) is one of the leading causes of mortality worldwide, and multiple single‑nucleotide polymorphisms of DNA repair genes have been found to be associated with CVD. The aim of the present study was to assess the effects of the genetic variants of RAD51 recombinase (RAD51) and 8‑oxoguanine DNA glycosylase (OGG1) on CVD through genotyping and statistical analysis. Regardless of whether there is a significant association or not, the genotyping data on these two polymorphisms are valuable, because there is limited availability of it in certain populations. A total of 240 blood samples were analyzed and genotyped using TaqMan genotyping; 120 were obtained from cases with a history of CVD, and 120 from cases with no history of CVD. A questionnaire was administered to gather information on age, demographics, sex and clinical features, and confirmation was carried out using medical records. The results of the present study confirmed that the polymorphism rs1052133 in OGG1 had no significant association with CVD. On the other hand, the polymorphism rs1801321 in RAD51 exhibited a significant association with CVD. Collectively, the results of the present study revealed that the polymorphism rs1801321 in RAD51 exhibited a significant association with CVD, however a larger sample size to confirm the present findings, may allow for the early identification of CVD and may aid in the decision‑making process concerning treatments for CVD.

Аbstrасt Objectives This study aimed to investigate in-hospital mortality rates in patients with coronavirus disease (COVID-19) according to enoxaparin and heparin use. Methods This retrospective cohort study included 962 patients admitted to two hospitals in Kuwait with a confirmed diagnosis of COVID-19. Cumulative all-cause mortality rate was the primary outcome. Results A total of 302 patients (males, 196 [64.9%]; mean age, 57.2 ± 14.6 years; mean body mass index, 29.8 ± 6.5 kg/m2) received anticoagulation therapy. Patients receiving anticoagulation treatment tended to have pneumonia (n = 275 [91.1%]) or acute respiratory distress syndrome (n = 106 [35.1%]), and high D-dimer levels (median [interquartile range]: 608 [523;707] ng/mL). The mortality rate in this group was high (n = 63 [20.9%]). Multivariable logistic regression, the Cox proportional hazards, and Kaplan-Meier models revealed that the use of therapeutic anticoagulation agents affected the risk of all-cause cumulative mortality. Conclusion Age, hypertension, pneumonia, therapeutic anticoagulation, and methylprednisolone use were found to be strong predictors of in-hospital mortality. In elderly hypertensive COVID-19 patients on therapeutic anticoagulation were found to have 2.3 times higher risk of in-hospital mortality. All cause in-hospital mortality rate in the therapeutic anticoagulation group was up to 21%.

JOJOBA (Simmondsia chinensis L.) is a dioecious perennial evergreen shrub that is native to the south-western deserts of North America, and has now been introduced to the Middle East. Currently, the global production of jojoba is low; this is mainly due to the high male -to-female ratio in plantations, since the plants are mainly established from seed. Hence, a proper male:female population ratio is almost impossible to maintain in the field, leading to reduced production. We report a breakthrough in the methodology for determining the sex of jojoba plants. Our research revealed that the jojoba genome contains a sequence of the SRY gene, which encodes a protein that is similar to that found in the human sex-determining region (SRY) gene. This region was amplified and matched with sequences that are found in papaya and humans. The jojoba-SRY (SRY gene) was amplified, and we closely matched its sequences with those in the papaya and human. The complete sequence of the DNA was deposited into the GenBank (MK991776, 360pb) database. Our newly developed method is rapid and straightforward, representing a breakthrough for sex determination strategies of jojoba plants at early developmental stages. The uniqueness of this approach is that it targets specific sequences in the SRY, a region that has been extensively studied in human genetics but is also apparently recognizable in plants. This useful molecular diagnostic tool is vital to agronomical breeding programs for sex determination in long-lived jojoba crops.

Objectives: To describe the baseline characteristics and to evaluate the risk factors for in-hospital mortality in patients admitted to hospitals with coronavirus disease (COVID-19) in Kuwait. Subjects and Methods: This retrospective cohort study analyzed data of patients admitted to two hospitals in Kuwait with COVID-19. The outcome was assessed by using multivariable analysis of factors affecting survival and mortality. Results: In 962 patients, the case fatality ratio was 9.04%. The mean age of nonsurvivors was 63.5 ± 14.8 years, and most deaths occurred in males (80.5%). For the whole sample, the source of transmission was significantly related to mortality and the median duration of in-hospital stay was 15 days (interquartile range: 2–52 days). In patients with high oxygen requirements, the case fatality rate was 96.6%. Multivariable analysis identified age, hypertension, cardiovascular disease (CVD), and dyspnea on presentation as independent risk factors for COVID-19 mortality. Conclusions: The mortality rate was higher in older patients with comorbidities such as hypertension and CVD. Early recognition of high-risk patients may help to improve care and reduce mortality.

The RECOVERY study documented lower 28-day mortality with the use of dexamethasone in hospitalized patients on invasive mechanical ventilation or oxygen with COVID-19 Pneumonia. We aimed to examine the practice patterns of steroids use, and their impact on mortality and length of stay in ICU. We retrospectively examined records of all patients with confirmed Covid 19 pneumonia admitted to the ICU of Dubai hospital from January 1st, 2020 - June 30th, 2020. We assigned patients to four groups (No steroids, low dose, medium dose, and high dose steroids). The primary clinical variable of interest was doses of steroids. Secondary outcomes were 28-day mortality and length of stay in ICU". We found variability in doses of steroid treatment. The most frequently used dose was the high dose. Patients who survived were on significantly higher doses of steroids and had significantly longer stays in ICU. The prescription of steroids in Covid-19 ARDS is variable. The dose of steroids impacts mortality rate and length of stay in ICU, although patients treated with high dose steroids seem to stay more days in ICU.

Sex determination in the early developmental stages of dioecious crops is economically-beneficial. During this study, a human homology of SRY gene was successfully identified in dioecious crops. SRY gene sequences of date palm and jojoba were submitted to GenBank under the accession numbers KC577225 and MK991776, respectively. This is the first report regarding the novel sex-determination methodology of four dioecious plants (jojoba, date palm, papaya, and pistachios). SRY sex gene was found in all the tested dioecious plant and human samples. This novel approach is simple and of significant importance for breeders. It facilitates the unambiguous selection of jojoba and date palm female plants at an early age and reduces the plantation cost of cultivating non-productive male plants. This is a rapid sex-determination technique for dioecious plants and mammals at an early stage. This technique specifically targets the SRY sequence that has been comprehensively investigated in humans. The kit development for the SRY-based sex determination of various crops is in progress.

The goal of this study was to investigate in-hospital mortality in patients suffering from acute respiratory syndrome coronavirus 2 (SARS-CoV-2) relative to the neutrophil to lymphocyte ratio (NLR) and to determine if there are gender disparities in outcome. Between February 26 and September 8, 2020, patients having SARS-CoV-2 infection were enrolled in this retrospective cohort research, which was categorized by NLR levels ≥9 and < 9. In total, 6893 patients were involved included of whom6591 had NLR <9, and 302 had NLR ≥9. The age of most of the patients in the NLR<9 group was 50 years, on the other hand, the age of most of the NLR ≥9 group patients was between 50 and 70 years. The majority of patients in both groups were male 2211 (66.1%). The ICU admission time and mortality rate for the patients with NLR ≥9 was significantly higher compared to patients with NLR <9. Logistic regression's outcome indicated that NLR ≥9 (odds ratio (OR), 24.9; 95% confidence interval (CI): 15.5-40.0; p < 0.001), male sex (OR, 3.5; 95% CI: 2.0-5.9; p < 0.001) and haemoglobin (HB) (OR, 0.95; 95% CI; 0.94-0.96; p < 0.001) predicted in-hospital mortality significantly. Additionally, Cox proportional hazards analysis (B = 4.04, SE = 0.18, HR = 56.89, p < 0.001) and Kaplan-Meier survival probability plots also indicated that NLR>9 had a significant effect on mortality. NLR ≥9 is an independent predictor of mortality(in-hospital) among SARS-CoV-2 patients.

Background: The aim of this study was to determine in-hospital mortality in patients presenting with severe acute respiratory syndrome corona virus 2 (SARS-CoV-2) and to evaluate for any differences in outcome according to sex differences. Methods: Patients with SRS-CoV-2 infection were recruited into this retrospective cohort study between February 26 and September 8, 2020 and stratified according to the sex differences. Results: In total of 3360 patients (mean age 44 +/- 17 years) were included, of whom 2221 (66%) were male. The average length of hospitalization was 13 days (range: 2-31 days). During hospitalization and follow-up 176 patients (5.24%) died. In-hospital mortality rates were significantly different according to gender (p=<0.001). Specifically, male gender was associated with significantly greater mortality when compared to female gender with results significant at an alpha of 0.05, LL = 28.67, df = 1, p = 0.001, suggesting that gender could reliably determine mortality rates. The coefficient for the males was significant, B = 1.02, SE = 0.21, HR = 2.78, p < 0.001, indicating that an observation in the male category will have a hazard 2.78 times greater than that in the female category. Multivariate logistic regression confirmed male patients admitted with SARS-CoV-2had higher cumulative all-cause in-hospital mortality (6.8% vs. 2.3%; adjusted odds ratio (aOR), 2.80; 95% (CI): [1.61-5.03]; p < 0.001). Conclusions: Male gender was an independent predictor of in-hospital mortality in this study. The mortality rate among male SARS-CoV-2 patients was 2.8 times higher when compared with females.

Controlling contagious diseases necessitates using diagnostic techniques that can detect infection in the early stages. Although different diagnostic tools exist, there are still challenges related to accuracy, rapidity, cost-effectiveness, and ease of use. Surface-enhanced Raman spectroscopy (SERS) is a rapid, simple, less expensive, and accurate method. We continue our previous work published on SERS detection of the SARS-CoV-2 receptor-binding domain (RBD) in water. In this work, we replace water with saliva to detect SARS-CoV-2 proteins at very low concentrations and during a very short time. We prepared a very low concentration of 10−9 M SARS-CoV-2 spike protein (S) and SARS-CoV-2 receptor-binding domain (RBD) in saliva to mimic a real case scenario. Then, we drop them on a SERS substrate. Using modified SERS measurements on the control and the sample containing the biomolecules, confirmed the sensitivity of the target identification. This technique provides different diagnostic solutions that are fast, simple, non-destructive and ultrasensitive. Simulation of the real-world of silicon wire covered with silver and gold, were performed using an effective and accurate tool, COMSOL Multiphysics software, for the enhancement properties study.

Background This study investigates in-hospital mortality amongst patients with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and its relation to serum levels of gamma-glutamyl transferase (GGT). Methods Patients were stratified according to serum levels of gamma-glutamyl transferase (GGT) (GGT<50 IU/L or GGT >= 50 IU/L). Results A total of 802 participants were considered, amongst whom 486 had GGT<50 IU/L and a mean age of 48.1 (16.5) years, whilst 316 had GGT >= 50 IU/L and a mean age of 53.8 (14.7) years. The chief sources of SARS-CoV-2 transmission were contact (366, 45.7%) and community (320, 40%). Most patients with GGT >= 50 IU/L had either pneumonia (247, 78.2%) or acute respiratory distress syndrome (ARDS) (85, 26.9%), whilst those with GGT<50 IU/L had hypertension (141, 29%) or diabetes mellitus (DM) (147, 30.2%). Mortality was higher amongst patients with GGT >= 50 IU/L (54, 17.1%) than amongst those with GGT<50 IU/L (29, 5.9%). More patients with GGT >= 50 required high (83, 27.6%) or low (104, 34.6%) levels of oxygen, whereas most of those with GGT<50 had no requirement of oxygen (306, 71.2%). Multivariable logistic regression analysis indicated that GGT >= 50 IU/L (odds ratio [OR]: 2.02, 95% confidence interval [CI]: 1.20-3.45, p=0.009), age (OR: 1.05, 95% CI: 1.03-1.07, p<0.001), hypertension (OR: 2.06, 95% CI: 1.19-3.63, p=0.011), methylprednisolone (OR: 2.96, 95% CI: 1.74-5.01, p<0.001) and fever (OR: 2.03, 95% CI: 1.15-3.68, p=0.016) were significant predictors of all-cause cumulative mortality. A Cox proportional hazards regression model (B = -0.68, SE =0.24, HR =0.51, p = 0.004) showed that patients with GGT<50 IU/L had a 0.51-times lower risk of all-cause cumulative mortality than patients with GGT >= 50 IU/L. Conclusion Higher levels of serum GGT were found to be an independent predictor of in-hospital mortality.

•In-hospital mortality in patients with SARS-CoV-2 on corticosteroid was evaluated.•Risk of mortality was 4.6 times higher in those with corticosteroid therapy.•Corticosteroid therapy patients had a longer hospital stay.

Objectives To assess the effectiveness and safety of tocilizumab, a humanised anti-interleukin-6 receptor antibody, in the treatment of critical or severe coronavirus disease 2019 (COVID-19) patients. Methods This was a retrospective cohort study of severe or critical COVID-19 patients (>= 18 years) admitted to one hospital in Kuwait. Fifty-one patients received intravenous tocilizumab, while 78 patients received the standard of care at the same hospital. Both groups were compared for clinical improvement and in-hospital mortality. Results The tocilizumab (TCZ) group had a significantly lower 28-day in-hospital mortality rate than the standard-of care-group (21.6% vs. 42.3% respectively; p = 0.015). Fifty-five per cent of patients in the TCZ group clinically improved vs. 11.5% in the standard-of-care group (p < 0.001). Using Cox-proportional regression analysis, TCZ treatment was associated with a reduced risk of mortality (adjusted hazard ratio 0.25; 95% CI: 0.11-0.61) and increased likelihood of clinical improvement (adjusted hazard ratio 4.94; 95% CI: 2.03-12.0), compared to the standard of care. The median C-reactive protein, D-dimer, procalcitonin, lactate dehydrogenase and ferritin levels in the tocilizumab group decreased significantly over the 14 days of follow-up. Secondary infections occurred in 19.6% of the TCZ group, and in 20.5% of the standard-of-care group, with no statistical significance (p = 0.900). Conclusion Tocilizumab was significantly associated with better survival and greater clinical improvement in severe or critical COVID-19 patients.

This study is done to estimаte in‐hоsрitаl mоrtаlity in раtients with severe асute resрirаtоry syndrоme соrоnаvirus 2 (SАRS‐СоV‐2) strаtified by Vitamin‐D (Vit‐D) levels. Раtients were strаtified ассоrding tо by serum 25‐hydroxy‐vitamin D (25(OH)Vit‐D) levels intо twо grоuрs, that is, 25(OH)Vit‐D less thаn 40 nmol/L аnd 25(OH)Vit‐D greаter thаn 40 nmol/L. А tоtаl оf 231 раtients were inсluded. Оf these, 120 (50.2%) оf the раtients hаd 25(OH)Vit‐D levels greаter thаn 40 nmol/L. The meаn аge wаs 49 ± 17 yeаrs, аnd 67% оf the раtients were mаles. The mediаn length оf оverаll hоsрitаl stаy wаs 18 [6; 53] dаys. The remаining 119 (49.8%) раtients hаd а 25(OH)Vit‐D less thаn 40 nmol/L. Vitamin D levels were seen as deficient in 63% of patients, insufficient in 25% and normal in 12%. Оverаll mоrtаlity wаs 17 раtients (7.1%) but statistically not signifiсаnt among the grоuрs (p = 0.986). The Kарlаn–Meier survivаl аnаlysis shоwed no significance based on an alpha of 0.05, LL = 0.36, df = 1, p = 0.548, indicating Vitamin_D_Levels was not able to adequately predict the hazard of Mortality. In this study, serum 25(OH)Vit‐D levels were found have no significance in terms of predicting the in‐hоsрitаl mortality in раtients with SАRS‐СоV‐2.

Background: The aim of this study was to determine in-hospital mortality in patients presenting with acute respiratory syndrome corona virus 2 (SARS-CoV-2) and to evaluate for any differences in outcome according to gender. Methods: Patients with SRS-CoV-2 infection were recruited into this retrospective cohort study between February 26 and September 8, 2020 and strаtified ассоrding tо the gender. Results: In tоtаl оf 3360 раtients (meаn аge 44 ± 17 years) were included, of whom 2221 (66%) were mаle. The average length of hospitalization was 13 days (range: 2–31 days). During hospitalization and follow-up 176 patients (5.24%) died. Mortality rates were significantly different according to gender (p=<0.001). Specifically, male gender was associated with significantly greater mortality when compared to female gender with results significant at an alpha of 0.05, LL = 28.67, df = 1, p = 0.001, suggesting that gender could reliably determine mortality rates. The coefficient for the males was significant, B = 1.02, SE = 0.21, HR = 2.78, p < .001, indicating that an observation in the male category will have a hazard 2.78 times greater than that in the female category. Multivariate logistic regression confirmed male patients admitted with SARS-CoV-2had higher сumulаtive аll-саuse in-hоsрitаl mоrtаlity (6.8% vs. 2.3%; аdjusted оdds rаtiо (аОR), 2.80; 95% (СI): [1.61 - 5.03]; р < 0.001). Conclusions: Male gender was an independent predictor of in-hospital death in this study. The mortality rate among male SARS-CoV-2 patients was 2.8 times higher when compared with females.

Аbstrасt Introduction This study aims to investigate in‐hоsрitаl mоrtаlity in severe асute resрirаtоry syndrоme соrоnаvirus 2 раtients strаtified by serum ferritin levels. Methods Patients were stratified based on ferritin levels (ferritin levels ≤ 1000 or >1000). Results Approximately 89% (118) of the patients with ferritin levels > 1000 had pneumonia, and 51% (67) had hypertension. Fever (97, 73.5%) and shortness of breath (80, 61%) were two major symptoms among the patients in this group. Logistic regression analysis indicated that ferritin level (odds ratio [OR] = 0.36, 95% confidence interval [CI] = 0.21–0.62; p < .001), male sex (OR = 2.63, 95% CI = 1.43–5.06; p = .003), hypertension (OR = 4.16, 95% CI = 2.42–7.36; p < .001) and pneumonia (OR = 8.48, 95% CI = 3.02–35.45; p < .001) had significance in predicting in‐hospital mortality. Additionally, the Cox proportional hazards analysis and Kaplan–Meier survival probability plot showed a higher mortality rate among patients with ferritin levels > 1000. Conclusion In this study, higher levels of serum ferritin were found to be an independent predictor of in‐hоsрitаl mоrtаlity.

Plant response to salt stress and the mechanism of salt tolerance have received major focus by plant biology researchers. Biotic stresses cause extensive losses in agricultural production globally, but abiotic stress causes significant increase in the methylglyoxal (MG) level of GlyoxalaseI (Gly I). Identification of salt-tolerant genes when characterizing their phenotypes will help to identify novel genes using polymerase chain reaction (PCR) to amplify the DNA coding region for glyoxalase I. This method is specific, requiring only genomic DNA and two pairs of PCR primers, and involving two successive PCR reactions. This method was used rapidly and easily identified glyoxalase I sequences as salt-tolerant genes from Jojoba (Simmondsia chinensis (Link) Schneider). In the present study, the glyoxalase I gene was isolated, amplified by PCR using gene-specific primers and sequenced from the jojoba plant, then compared with other glyoxalase I sequences in other plants and glyoxalase I genes like in Brassica napus, ID: KT720495.1; Brassica juncea ID: Y13239.1, Arachis hypogaea; ID: DQ989209.2; and Arabidopsis thaliana L, ID: AAL84986. The structural gene of glyoxalase I, when sequenced and analyzed, revealed that the uninterrupted open reading frame (ORF) of jojoba Gly I (Jojo-Gly I) spans 775 bp, corresponding to 185 amino acid residues, and shares 45.2% amino acid sequence identity to jojoba (Jojo-Gly I). The cloned ORF, in a multicopy constitutive expression plasmid, complemented the Jojo-Gly I, confirming that the encoded Jojo-Gly I in jojoba showed some homology with other known glyoxalase I sequences of plants.

Epstein-Barr virus (EBV), is an oncogenic gamma-herpesvirus, which is associated with malignant diseases of B cells, T cells, and epithelial cells. EB viruses have large DNA genomes of more than 170 kb that are difficult to clone and manipulate. Here we describe 2 different approaches for cloning whole EBV genomes of diverse strains for reverse genetics studies. The first approach used CRISPR/Cas9-mediated cloning of the entire EBV genome into a bacterial artificial chromosome (BAC) vector using homologous recombination in B cells. This method allowed the cloning of the type 2 EBV strain Jijoye for the first time, but the BAC-clones are unstable. This strategy is being modified by recoding the homology regions to make the clones more stable. The second approach involves transformation-associated recombination (TAR) cloning of EBV fragments and their assembly in yeast, which will allow for mixing and matching DNA regions from different EBV strains for functional studies. This approach is based on TAR cloning of the EBV genome as 10 overlapping fragments, which average 17 kilobases long, using the natural homologous recombination processes of the yeast. Subsequent assembly of all the overlapping fragments is undertaken in yeast or by Gibson assembly to reconstitute the infectious EBV clone. Two fragments from EBV strains B95-8 and AG876 were captured and isolated successfully, but at low efficiency. We are currently improving the TAR cloning efficiency by increasing the size of the capture homology regions to approximately 500 bp coupled with CRISPR/Cas-9-mediated fragmentation of the EBV genome.

The Epstein-Barr virus (EBV) nuclear antigen leader protein (EBNA-LP) is the first viral latency-associated protein produced after EBV infection of resting B cells. Its role in B cell transformation is poorly defined, but it has been reported to enhance gene activation by the EBV protein EBNA2 in vitro. We generated EBNA-LP knockout (LPKO) EBVs containing a STOP codon within each repeat unit of internal repeat 1 (IR1). EBNA-LP-mutant EBVs established lymphoblastoid cell lines (LCLs) from adult B cells at reduced efficiency, but not from umbilical cord B cells, which died approximately two weeks after infection. Adult B cells only established EBNA-LP-null LCLs with a memory (CD27+) phenotype. Quantitative PCR analysis of virus gene expression after infection identified both an altered ratio of the EBNA genes, and a dramatic reduction in transcript levels of both EBNA2-regulated virus genes (LMP1 and LMP2) and the EBNA2-independent EBER genes in the first 2 weeks. By 30 days post infection, LPKO transcription was the same as wild-type EBV. In contrast, EBNA2-regulated cellular genes were induced efficiently by LPKO viruses. Chromatin immunoprecipitation revealed that EBNA2 and the host transcription factors EBF1 and RBPJ were delayed in their recruitment to all viral latency promoters tested, whereas these same factors were recruited efficiently to several host genes, which exhibited increased EBNA2 recruitment. We conclude that EBNA-LP does not simply co-operate with EBNA2 in activating gene transcription, but rather facilitates the recruitment of several transcription factors to the viral genome, to enable transcription of virus latency genes. Additionally, our findings suggest that EBNA-LP is essential for the survival of EBV-infected naïve B cells.

ABSTRACT Epstein-Barr virus (EBV) is a ubiquitous pathogen of humans that can cause several types of lymphoma and carcinoma. Like other herpesviruses, EBV has diversified through both coevolution with its host and genetic exchange between virus strains. Sequence analysis of the EBV genome is unusually challenging because of the large number and lengths of repeat regions within the virus. Here we describe the sequence assembly and analysis of the large internal repeat 1 of EBV (IR1; also known as the BamW repeats) for more than 70 strains. The diversity of the latency protein EBV nuclear antigen leader protein (EBNA-LP) resides predominantly within the exons downstream of IR1. The integrity of the putative BWRF1 open reading frame (ORF) is retained in over 80% of strains, and deletions truncating IR1 always spare BWRF1. Conserved regions include the IR1 latency promoter (Wp) and one zone upstream of and two within BWRF1. IR1 is heterogeneous in 70% of strains, and this heterogeneity arises from sequence exchange between strains as well as from spontaneous mutation, with interstrain recombination being more common in tumor-derived viruses. This genetic exchange often incorporates regions of <1 kb, and allelic gene conversion changes the frequency of small regions within the repeat but not close to the flanks. These observations suggest that IR1—and, by extension, EBV—diversifies through both recombination and breakpoint repair, while concerted evolution of IR1 is driven by gene conversion of small regions. Finally, the prototype EBV strain B95-8 contains four nonconsensus variants within a single IR1 repeat unit, including a stop codon in the EBNA-LP gene. Repairing IR1 improves EBNA-LP levels and the quality of transformation by the B95-8 bacterial artificial chromosome (BAC). IMPORTANCE Epstein-Barr virus (EBV) infects the majority of the world population but causes illness in only a small minority of people. Nevertheless, over 1% of cancers worldwide are attributable to EBV. Recent sequencing projects investigating virus diversity to see if different strains have different disease impacts have excluded regions of repeating sequence, as they are more technically challenging. Here we analyze the sequence of the largest repeat in EBV (IR1). We first characterized the variations in protein sequences encoded across IR1. In studying variations within the repeat of each strain, we identified a mutation in the main laboratory strain of EBV that impairs virus function, and we suggest that tumor-associated viruses may be more likely to contain DNA mixed from two strains. The patterns of this mixing suggest that sequences can spread between strains (and also within the repeat) by copying sequence from another strain (or repeat unit) to repair DNA damage.