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排序方式: 共有421条查询结果,搜索用时 12 毫秒
81.
Sanne van den Berg Jrmie Vandenplas Fred A. van Eeuwijk Marcos S. Lopes Roel F. Veerkamp 《Zeitschrift für Tierzüchtung und Züchtungsbiologie》2019,136(6):418-429
Significance testing for genome‐wide association study (GWAS) with increasing SNP density up to whole‐genome sequence data (WGS) is not straightforward, because of strong LD between SNP and population stratification. Therefore, the objective of this study was to investigate genomic control and different significance testing procedures using data from a commercial pig breeding scheme. A GWAS was performed in GCTA with data of 4,964 Large White pigs using medium density, high density or imputed whole‐genome sequence data, fitting a genomic relationship matrix based on a leave‐one–chromosome‐out approach to account for population structure. Subsequently, genomic inflation factors were assessed on whole‐genome level and the chromosome level. To establish a significance threshold, permutation testing, Bonferroni corrections using either the total number of SNPs or the number of independent chromosome fragments, and false discovery rates (FDR) using either the Benjamini–Hochberg procedure or the Benjamini and Yekutieli procedure were evaluated. We found that genomic inflation factors did not differ between different density genotypes but do differ between chromosomes. Also, the leave‐one‐chromosome‐out approach for GWAS or using the pedigree relationships did not account appropriately for population stratification and gave strong genomic inflation. Regarding different procedures for significance testing, when the aim is to find QTL regions that are associated with a trait of interest, we recommend applying the FDR following the Benjamini and Yekutieli approach to establish a significance threshold that is adjusted for multiple testing. When the aim is to pinpoint a specific mutation, the more conservative Bonferroni correction based on the total number of SNPs is more appropriate, till an appropriate method is established to adjust for the number of independent tests. 相似文献
82.
83.
Jenkins SJ Ruckerl D Cook PC Jones LH Finkelman FD van Rooijen N MacDonald AS Allen JE 《Science (New York, N.Y.)》2011,332(6035):1284-1288
A defining feature of inflammation is the accumulation of innate immune cells in the tissue that are thought to be recruited from the blood. We reveal that a distinct process exists in which tissue macrophages undergo rapid in situ proliferation in order to increase population density. This inflammatory mechanism occurred during T helper 2 (T(H)2)-related pathologies under the control of the archetypal T(H)2 cytokine interleukin-4 (IL-4) and was a fundamental component of T(H)2 inflammation because exogenous IL-4 was sufficient to drive accumulation of tissue macrophages through self-renewal. Thus, expansion of innate cells necessary for pathogen control or wound repair can occur without recruitment of potentially tissue-destructive inflammatory cells. 相似文献
84.
Pike FS Berg J King NW Penninck DG Webster CR 《Journal of the American Veterinary Medical Association》2004,224(10):1615-1622
OBJECTIVE: To determine long-term outcome of dogs with gallbladder mucocele. DESIGN: Retrospective study. ANIMALS: 30 dogs with gallbladder mucocele, including 23 that underwent cholecystectomy. PROCEDURE: Medical records were reviewed for signalment, history, and clinical, ultrasonographic, and surgical findings. Follow-up information was obtained for all dogs that survived the perioperative hospitalization period. RESULTS: 23 dogs had signs of systemic illness; 7 had no clinical signs. Median values for serum activities of alanine aminotransferase and alkaline phosphatase, serum total bilirubin concentration, and total WBC count were significantly higher among dogs with gallbladder rupture than among dogs without rupture. Sensitivity of sonography for detection of rupture was 85.7%. Overall perioperative mortality rate for dogs that underwent cholecystectomy was 21.7%; mortality rate was not significantly greater for dogs with rupture. Aerobic bacteria were isolated from the bile or gallbladder wall in 8.7% of dogs. All 18 dogs discharged from the hospital had complete resolution of clinical signs. In dogs that underwent in-hospital reexamination, serum liver enzyme activities were significantly decreased, compared with preoperative activities. Persistent increases in serum activities of 1 or more liver enzymes were detected in 9 of 12 dogs; 6 of 12 dogs had persistent abnormalities in hepatic echogenicity. Mean follow-up period was 13.9 months. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that cholecystectomy is an effective treatment for gallbladder mucocele. Although perioperative mortality rate is high, prognosis after discharge from the hospital is excellent. Rupture of the gallbladder warrants emergency surgical intervention but does not preclude a positive outcome. 相似文献
85.
David G. Heckel Linda J. Gahan Fred Gould Joanne C. Daly Stephen Trowell 《Pest management science》1997,51(3):251-258
Genetic linkage maps of Heliothis virescens and Helicoverpa armigera are being used to identify and characterize resistance-conferring genes. The insensitive acetylcholinesterase conferring resistance to organophosphorus insecticides and the insensitive sodium channel conferring resistance to pyrethroids have both been mapped in H. virescens. The linkage mapping approach permits a genetic dissection of resistance, even when the mode of action and lethal target are not precisely known, such as for the insecticidal toxins from the bacterium Bacillus thuringiensis (Bt). We have identified and mapped a major Bt-resistance locus in a strain of H. virescens exhibiting up to 10000-fold resistance to Cry1Ac toxin and are currently developing a linkage map for H. armigera with a set of ‘anchor’ loci to facilitate comparison with H. virescens. Both species are currently experiencing their first significant selective pressure in the field by transgenic cotton expressing Cry1Ac, and timely identification of resistance mechanisms and their underlying genetic basis will be essential in successfully managing the Bt resistance that will eventually appear. ©1997 SCI 相似文献
86.
B. I. G. Haussmann H. Fred Rattunde E. Weltzien‐Rattunde P. S. C. Traoré K. vom Brocke H. K. Parzies 《Journal of Agronomy and Crop Science》2012,198(5):327-339
Semi‐arid and subhumid West Africa is characterized by high inter‐annual rainfall variability, with variable onset of the rainy season, somewhat more predictable endings, and drought or excess water occurrence at any time during the growing season. Climate change is predicted to increase this variability. This article summarizes options for plant breeders to enhance the adaptation of pearl millet (Pennisetum glaucum [L.] R. Br.) and sorghum (Sorghum bicolor [L.] Moench) to climate variability in West Africa. Developing variety types with high degrees of heterozygosity and genetic heterogeneity for adaptation traits helps achieving better individual and population buffering capacity. Traits that potentially enhance adaptive phenotypic plasticity or yield stability in variable climates include photoperiod‐sensitive flowering, plastic tillering, flooding tolerance, seedling heat tolerance and phosphorus efficiency. Farmer‐participatory dynamic gene pool management using broad‐based populations and diverse selection environments is useful to develop new diverse germplasm adapted to specific production constraints including climate variability. For sustainable productivity increase, improved cultivars should respond to farmer‐adoptable soil fertility management and water harvesting techniques. Larger‐scale, on‐farm participatory testing will enable assessments of varietal performance under evolving climatic variability, provide perspective on needs and opportunities and enhance adoption. Strengthening seed systems will be required to achieve sustainable impacts. 相似文献
87.
Intrauterine inoculation of pony mares with the bacterium that is the causative agent of contagious equine metritis (CEM) resulted in clinical disease. A humoral immune response could be detected by agglutination and complement fixation (CF), and in some cases precipitating antibody was found by immunodiffusion tests. Agglutinating antibody was the most reliable serological indicator of overt infection and was detected in 8 of 28 mares after initial intrauterine inoculation of 3–4 × 105 bacteria. Seventy percent of mares given a second inoculation and all mares given a third inoculation of 3–4 × 105 bacteria produced detectable agglutinating antibody. Only two of five mares given the third inoculation developed detectable complement-fixing antibody. Only one mare showed evidence of reinfection after a second or third intrauterine inoculation. All of the mares given a single intrauterine inoculum of ≥ 8 × 108 bacteria produced agglutinating antibody 10 to 30 days postinoculation (DPI) and 86% gave a positive CF test 10 to 20 DPI. Only mares with an agglutination titer of 320 or more produced precipitating antibody. Sera were considered positive in agglutination tests if they were reactive at a dilution of greater than 4 and positive in CF tests if they were reactive at a dilution of 4 or greater.Pony serum frozen at ?70°C was anticomplementary (AC). Treatment at 56°C abolished AC activity and revealed enhancing or procomplementary activity with guinea pig complement. Procomplementary activity could be abolished by treatment of heated pony serum with formaldehyde, which increased CF titers ≥ threefold in weakly reactive sera. 相似文献
88.
89.
Although signals controlled by single molecules are expected to be inherently variable, rod photoreceptors generate reproducible responses to single absorbed photons. We show that this unexpected reproducibility-the consistency of amplitude and duration of rhodopsin activity-varies in a graded and systematic manner with the number but not the identity of phosphorylation sites on rhodopsin's C terminus. These results indicate that each phosphorylation site provides an independent step in rhodopsin deactivation and that collectively these steps tightly control rhodopsin's active lifetime. Other G protein cascades may exploit a similar mechanism to encode accurately the timing and number of receptor activation. 相似文献
90.
For characterization of sequence and posttranslational modifications, molecular and fragment ion mass data from ionizing and dissociating a protein in the mass spectrometer are far more specific than are masses of peptides from the protein's digestion. We extend the approximately 500-residue, approximately 50-kilodalton (kD) dissociation limitation of this top-down methodology by using electrospray additives, heated vaporization, and separate noncovalent and covalent bond dissociation. This process can cleave 287 interresidue bonds in the termini of a 1314-residue (144-kD) protein, specify previously unidentified disulfide bonds between 8 of 27 cysteines in a 1714-residue (200-kD) protein, and correct sequence predictions in two proteins, one with 2153 residues (229 kD). 相似文献