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| 2. |
- Beal, Jacob, et al.
(författare)
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Robust estimation of bacterial cell count from optical density
- 2020
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Ingår i: Communications Biology. - : Springer Science and Business Media LLC. - 2399-3642. ; 3:1
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Tidskriftsartikel (refereegranskat)abstract
- Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data.
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| 3. |
- Chen, Zhi-Qiang, et al.
(författare)
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Leveraging breeding programs and genomic data in Norway spruce (Picea abies L. Karst) for GWAS analysis
- 2021
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Ingår i: Genome Biology. - : BioMed Central (BMC). - 1465-6906 .- 1474-760X. ; 22:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: Genome-wide association studies (GWAS) identify loci underlying the variation of complex traits. One of the main limitations of GWAS is the availability of reliable phenotypic data, particularly for long-lived tree species. Although an extensive amount of phenotypic data already exists in breeding programs, accounting for its high heterogeneity is a great challenge. We combine spatial and factor-analytics analyses to standardize the heterogeneous data from 120 field experiments of 483,424 progenies of Norway spruce to implement the largest reported GWAS for trees using 134 605 SNPs from exome sequencing of 5056 parental trees.Results: We identify 55 novel quantitative trait loci (QTLs) that are associated with phenotypic variation. The largest number of QTLs is associated with the budburst stage, followed by diameter at breast height, wood quality, and frost damage. Two QTLs with the largest effect have a pleiotropic effect for budburst stage, frost damage, and diameter and are associated with MAP3K genes. Genotype data called from exome capture, recently developed SNP array and gene expression data indirectly support this discovery.Conclusion: Several important QTLs associated with growth and frost damage have been verified in several southern and northern progeny plantations, indicating that these loci can be used in QTL-assisted genomic selection. Our study also demonstrates that existing heterogeneous phenotypic data from breeding programs, collected over several decades, is an important source for GWAS and that such integration into GWAS should be a major area of inquiry in the future.
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| 4. |
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| 5. |
- Bernhardsson, Carolina, et al.
(författare)
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Development of a highly efficient 50K single nucleotide polymorphism genotyping array for the large and complex genome of Norway spruce (Picea abies L. Karst) by whole genome resequencing and its transferability to other spruce species
- 2021
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Ingår i: Molecular Ecology Resources. - : John Wiley & Sons. - 1755-098X .- 1755-0998. ; 21:3, s. 880-896
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Tidskriftsartikel (refereegranskat)abstract
- Norway spruce (Picea abies L. Karst) is one of the most important forest tree species with significant economic and ecological impact in Europe. For decades, genomic and genetic studies on Norway spruce have been challenging due to the large and repetitive genome (19.6 Gb with more than 70% being repetitive). To accelerate genomic studies, including population genetics, genome-wide association studies (GWAS) and genomic selection (GS), in Norway spruce and related species, we here report on the design and performance of a 50K single nucleotide polymorphism (SNP) genotyping array for Norway spruce. The array is developed based on whole genome resequencing (WGS), making it the first WGS-based SNP array in any conifer species so far. After identifying SNPs using genome resequencing data from 29 trees collected in northern Europe, we adopted a two-step approach to design the array. First, we built a 450K screening array and used this to genotype a population of 480 trees sampled from both natural and breeding populations across the Norway spruce distribution range. These samples were then used to select high-confidence probes that were put on the final 50K array. The SNPs selected are distributed over 45,552 scaffolds from the P. abies version 1.0 genome assembly and target 19,954 unique gene models with an even coverage of the 12 linkage groups in Norway spruce. We show that the array has a 99.5% probe specificity, >98% Mendelian allelic inheritance concordance, an average sample call rate of 96.30% and an SNP call rate of 98.90% in family trios and haploid tissues. We also observed that 23,797 probes (50%) could be identified with high confidence in three other spruce species (white spruce [Picea glauca], black spruce [P. mariana] and Sitka spruce [P. sitchensis]). The high-quality genotyping array will be a valuable resource for genetic and genomic studies in Norway spruce as well as in other conifer species of the same genus.
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| 6. |
- Chen, Zhi-Qiang, et al.
(författare)
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Genetic architecture behind developmental and seasonal control of tree growth and wood properties in Norway spruce
- 2022
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Ingår i: Frontiers in Plant Science. - : Frontiers Media SA. - 1664-462X. ; 13
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Tidskriftsartikel (refereegranskat)abstract
- Genetic control of tree growth and wood formation varies depending on the age of the tree and the time of the year. Single-locus, multi-locus, and multi-trait genome-wide association studies (GWAS) were conducted on 34 growth and wood property traits in 1,303 Norway spruce individuals using exome capture to cover similar to 130K single-nucleotide polymorphisms (SNPs). GWAS identified associations to the different wood traits in a total of 85 gene models, and several of these were validated in a progenitor population. A multilocus GWAS model identified more SNPs associated with the studied traits than single-locus or multivariate models. Changes in tree age and annual season influenced the genetic architecture of growth and wood properties in unique ways, manifested by non-overlapping SNP loci. In addition to completely novel candidate genes, SNPs were located in genes previously associated with wood formation, such as cellulose synthases and a NAC transcription factor, but that have not been earlier linked to seasonal or age-dependent regulation of wood properties. Interestingly, SNPs associated with the width of the year rings were identified in homologs of Arabidopsis thaliana BARELY ANY MERISTEM 1 and rice BIG GRAIN 1, which have been previously shown to control cell division and biomass production. The results provide toots for future Norway spruce breeding and functional studies.
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| 7. |
- Guo, Ying, et al.
(författare)
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Researching on the fine structure and admixture of the worldwide chicken population reveal connections between populations and important events in breeding history
- 2021
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Ingår i: Evolutionary Applications. - : John Wiley & Sons. - 1752-4571.
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Tidskriftsartikel (refereegranskat)abstract
- Here, we have evaluated the general genomic structure and diversity and studied the divergence resulting from selection and historical admixture events for a collection of worldwide chicken breeds. In total, 636 genomes (43 populations) were sequenced from chickens of American, Chinese, Indonesian, and European origin. Evaluated populations included wild junglefowl, rural indigenous chickens, breeds that have been widely used to improve modern western poultry populations and current com-mercial stocks bred for efficient meat and egg production. In-depth characteriza-tions of the genome structure and genomic relationships among these populations were performed, and population admixture events were investigated. In addition, the genomic architectures of several domestication traits and central documented events in the recent breeding history were explored. Our results provide detailed insights into the contributions from population admixture events described in the historical literature to the genomic variation in the domestic chicken. In particular, we find that the genomes of modern chicken stocks used for meat production both in eastern (Asia) and western (Europe/US) agriculture are dominated by contributions from heavy Asian breeds. Further, by exploring the link between genomic selective divergence and pigmentation, connections to functional genes feather coloring were confirmed.
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| 8. |
- Holmqvist, Anna Sällfors, et al.
(författare)
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Assessment of Late Mortality Risk after Allogeneic Blood or Marrow Transplantation Performed in Childhood
- 2018
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Ingår i: JAMA Oncology. - : American Medical Association (AMA). - 2374-2437. ; 4:12
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Tidskriftsartikel (refereegranskat)abstract
- Importance: Allogeneic blood or marrow transplantation (BMT) is a curative option for malignant and nonmalignant diseases of childhood. However, little is known about trends in cause-specific late mortality in this population during the past 3 decades. Objectives: To examine cause-specific late mortality among individuals who have lived 2 years or more after allogeneic BMT performed in childhood and whether rates of late mortality have changed over time. Design, Setting, and Participants: A retrospective cohort study was conducted of individuals who lived 2 years or more after undergoing allogeneic BMT performed in childhood between January 1, 1974, and December 31, 2010. The end of follow-up was December 31, 2016. Exposure: Allogeneic BMT performed in childhood. Main Outcomes and Measures: All-cause mortality, relapse-related mortality, and non-relapse-related mortality. Data on vital status and causes of death were collected using medical records, the National Death Index Plus Program, and Accurint databases. Results: Among 1388 individuals (559 females and 829 males) who lived 2 years or more after allogeneic BMT performed in childhood, the median age at transplantation was 14.6 years (range, 0-21 years). In this cohort, there was a total of 295 deaths, yielding an overall survival rate of 79.3% at 20 years after BMT. The leading causes of death were infection and/or chronic graft-vs-host disease (121 of 244 [49.6%]), primary disease (60 of 244 [24.6%]), and subsequent malignant neoplasms (45 of 244 [18.4%]). Overall, the cohort had a 14.4-fold increased risk for death (95% CI, 12.8-16.1) compared with the general population (292 deaths observed; 20.3 deaths expected). Relative mortality remained elevated at 25 years or more after BMT (standardized mortality ratio, 2.9; 95% CI, 2.0-4.1). The absolute excess risk for death from any cause was 12.0 per 1000 person-years (95% CI, 10.5-13.5). The cumulative incidence of non-relapse-related mortality exceeded that of relapse-related mortality throughout follow-up. The 10-year cumulative incidence of late mortality decreased over time (before 1990, 18.9%; 1990-1999, 12.8%; 2000-2010, 10.9%; P =.002); this decrease remained statistically significant after adjusting for demographic and clinical factors (referent group: <1990; 1990-1999: hazard ratio, 0.64; 95% CI, 0.47-0.89; P =.007; 2000-2010: hazard ratio, 0.49; 95% CI, 0.31-0.76; P =.002; P <.001 for trend). Conclusions and Relevance: Late mortality among children undergoing allogeneic BMT has decreased during the past 3 decades. However, these patients remain at an elevated risk of late mortality even 25 years or more after transplantation when compared with the general population, necessitating lifelong follow-up.
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| 9. |
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| 10. |
- Holmqvist, Anna Sällfors, et al.
(författare)
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Late Mortality after Allogeneic Bone Marrow Transplantation in Childhood for Bone Marrow Failure Syndromes and Severe Aplastic Anemia
- 2019
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Ingår i: Biology of Blood and Marrow Transplantation. - : Elsevier BV. - 1083-8791. ; 25:4, s. 749-755
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Tidskriftsartikel (refereegranskat)abstract
- Children with bone marrow failure syndromes and severe aplastic anemia (SAA) are treated with allogeneic blood or marrow transplantation (BMT). However, there is a paucity of studies examining late mortality risk after allogeneic BMT performed in childhood for bone marrow failure syndromes and SAA and evaluating how this risk differs between these diseases. We investigated cause-specific late mortality in 2-year survivors of allogeneic BMT for bone marrow failure syndromes and SAA performed before age 22 years between 1974 and 2010 at 2 US transplantation centers. Vital status information was collected from medical records, the National Death Index, and Accurint databases. Overall survival was calculated using Kaplan-Meier techniques. The standardized mortality ratio (SMR) was calculated using age- sex-, and calendar-specific mortality rates from the Centers for Disease Control and Prevention. Among the 2-year survivors of bone marrow failure syndromes (n = 120) and SAA (n = 147), there were 15 and 19 deaths, respectively, yielding an overall survival of 86.4% for bone marrow failure syndromes and 93.1% for SAA at 15 years post-BMT. Compared with the general population, patients with bone marrow failure syndromes were at a higher risk for premature death (SMR, 22.7; 95% CI, 13.1 to 36.2) compared with those with SAA (SMR, 4.5; 95% CI, 2.8 to 7.0) (P <.0001). The elevated relative risk persisted at ≥15 years after BMT for both diseases. The hazard of all-cause late mortality was 2.9-fold (95% CI, 1.1 to 7.3) higher in patients with bone marrow failure syndromes compared with those with SAA. The high late mortality risk in recipients of allogeneic BMT in childhood for bone marrow failure syndromes calls for intensified life-long follow-up.
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