scholarly journals PSV-13 Genetic parameters and quantitative trait loci for heat stress related traits in sheep

2020 ◽  
Vol 98 (Supplement_3) ◽  
pp. 163-164
Author(s):  
Devin R Jacobs ◽  
Claudia E Silvera-Rojas ◽  
Jennifer M Bormann ◽  
Terry A Gipson ◽  
Arthur L Goetsch ◽  
...  
Keyword(s):  
Heat Stress ◽  
Quantitative Trait Loci ◽  
Rectal Temperature ◽  
Quantitative Trait ◽  
Fixed Effects ◽  
Univariate Analysis ◽  
Average Daily Gain ◽  
The United States ◽  
Nucleotide Polymorphisms ◽  
Trait Loci

Abstract Greater selection emphasis has been placed on efficiency than on fitness in livestock populations over the last several decades. Heat stress is a concern in production systems due to the negative effects on production, reproduction, and immunity. The objective of the study was to estimate variance components and identify quantitative trait loci (QTL) for heat stress related traits in sheep. A total of 125 Dorper, Katahdin, and St. Croix ewes originating from four regions of the United States were selected for the experiment. Animals were separated into four trials due to facility limitations. Data were collected for each trial over four consecutive two-week periods in an environmentally controlled facility with targeted heat load index (HLI) for daytime/nighttime of 70/70, 85/77, 90/77, and 95/81. Body weight was collected three times per week and rectal temperature was collected weekly. Black globe temperature and humidity were measured every 15 minutes. Animals were genotyped using the Illumina OvineSNP50 BeadChip. After quality control, 49,396 effective single nucleotide polymorphisms were included in the univariate analysis performed with the BLUPF90 suite of programs. Fixed effects in the models included region of origin, breed, trial, and age as a covariate. Traits analyzed included rectal temperature at 95 HLI (RT95), feed intake at 95 HLI (FI95), and average daily gain for the period for HLI between 90 and 95 (ADG). Heritabilities for RT95, FI95, and ADG were 0.35, 0.10, and 0.10, respectively. Largest effect QTL were identified on chromosomes 23, 9, and 6 for RT95, chromosomes 9, 2, and 20 for FI95, and chromosomes 6, 1, and 5 for ADG. Many of the regions identified have also been associated with weight and carcass traits in other studies, but few had obvious connections to the heat stress related response. In conclusion, results suggest selection could improve heat tolerance in sheep.

scholarly journals Quantitative Trait Loci Associated with Rotylenchulus reniformis Host Suitability in Soybean

2020 ◽  
Vol 110 (9) ◽  
pp. 1511-1521
Author(s):  
Juliet Wilkes ◽  
Christopher Saski ◽  
Mariola Klepadlo ◽  
Benjamin Fallen ◽  
Paula Agudelo
Keyword(s):  
Quantitative Trait Loci ◽  
Qtl Analysis ◽  
Quantitative Trait ◽  
The United States ◽  
Host Suitability ◽  
Reniform Nematode ◽  
Rotylenchulus Reniformis ◽  
Chromosome 18 ◽  
Nematode Reproduction ◽  
Trait Loci

Reniform nematode (Rotylenchulus reniformis) is a yield-limiting pathogen of soybean (Glycine max) in the southeastern region of the United States. A population of 250 recombinant inbred lines (RIL) (F2:8) developed from a cross between reniform nematode resistant soybean cultivar Forrest and susceptible cultivar Williams 82 was utilized to identify regions associated with host suitability. A genetic linkage map was constructed using single-nucleotide polymorphism markers generated by genotyping-by-sequencing. The phenotype was measured in the RIL population and resistance was characterized using normalized and transformed nematode reproduction indices in an optimal univariate cluster analysis. Quantitative trait loci (QTL) analysis using normalized phenotype scores identified two QTLs on each arm of chromosome 18 (rrn-1 and rrn-2). The same QTL analysis performed with log10(x) transformed phenotype data also identified two QTLs: one on chromosome 18 overlapping the same region in the other analysis (rrn-1), and one on chromosome 11 (rrn-3). While rrn-1 and rrn-3 have been reported associated with reduced reproduction of reniform nematode, this is the first report of the rrn-2 region associated with host suitability to reniform nematode. The resistant parent allele at rrn-2 showed an inverse relationship with the resistance phenotype, correlating with an increase in nematode reproduction or host suitability. Several candidate genes within these regions corresponded with host plant defense systems. Interestingly, a characteristic pathogen resistance gene with a leucine-rich repeat was discovered within rrn-2. These genetic markers can be used by soybean breeders in marker-assisted selection to develop lines with resistance to reniform nematode.

scholarly journals QTLs Associated with Resistance to Cardiomyopathy Syndrome in Atlantic Salmon

2019 ◽  
Vol 110 (6) ◽  
pp. 727-737 ◽  
Author(s):  
Solomon Boison ◽  
Jingwen Ding ◽  
Erica Leder ◽  
Bjarne Gjerde ◽  
Per Helge Bergtun ◽  
...  
Keyword(s):  
Quantitative Trait Loci ◽  
Atlantic Salmon ◽  
Genetic Correlation ◽  
Survival Data ◽  
Quantitative Trait ◽  
Challenge Test ◽  
Nucleotide Polymorphisms ◽  
Heart Atrium ◽  
Genomic Heritability ◽  
Trait Loci

Abstract Cardiomyopathy syndrome (CMS) caused by piscine myocarditis virus is a major disease affecting the Norwegian Atlantic salmon industry. Three different populations of Atlantic salmon from the Mowi breeding program were used in this study. The first 2 populations (population 1 and 2) were naturally infected in a field outbreak, while the third population (population 3) went through a controlled challenged test. The aim of the study was to estimate the heritability, the genetic correlation between populations and perform genome-wide association analysis for resistance to this disease. Survival data from population 1 and 2 and heart atrium histology score data from population 3 was analyzed. A total of 571, 4312, and 901 fish from population 1, 2, and 3, respectively were genotyped with a noncommercial 55,735 Affymetrix marker panel. Genomic heritability ranged from 0.12 to 0.46 and the highest estimate was obtained from the challenge test dataset. The genetic correlation between populations was moderate (0.51–0.61). Two chromosomal regions (SSA27 and SSA12) contained single nucleotide polymorphisms associated with resistance to CMS. The highest association signal (P = 6.9751 × 10−27) was found on chromosome 27. Four genes with functional roles affecting viral resistance (magi1, pi4kb, bnip2, and ha1f) were found to map closely to the identified quantitative trait loci (QTLs). In conclusion, genetic variation for resistance to CMS was observed in all 3 populations. Two important quantitative trait loci were detected which together explain half of the total genetic variance, suggesting strong potential application for marker-assisted selection and genomic predictions to improve CMS resistance.

scholarly journals Quantitative trait loci identified for blood chemistry components of an advanced intercross line of chickens under heat stress

BMC Genomics ◽  
2016 ◽  
Vol 17 (1) ◽  
Author(s):  
Angelica Van Goor ◽  
Christopher M. Ashwell ◽  
Michael E. Persia ◽  
Max F. Rothschild ◽  
Carl J. Schmidt ◽  
...  
Keyword(s):  
Heat Stress ◽  
Quantitative Trait Loci ◽  
Quantitative Trait ◽  
Blood Chemistry ◽  
Advanced Intercross Line ◽  
Trait Loci

scholarly journals Two Independent Quantitative Trait Loci Are Responsible for Novel Resistance to Beet curly top virus in Common Bean Landrace G122

2010 ◽  
Vol 100 (10) ◽  
pp. 972-978 ◽  
Author(s):  
Richard C. Larsen ◽  
Chester J. Kurowski ◽  
Phillip N. Miklas
Keyword(s):  
Quantitative Trait Loci ◽  
Linkage Group ◽  
Common Bean ◽  
Quantitative Trait ◽  
Rapd Marker ◽  
The United States ◽  
Effective Control ◽  
Minor Effect ◽  
Beet Curly Top Virus ◽  
Trait Loci

Beet curly top virus, often referred to as Curly top virus (CTV), is an important virus disease of common bean in the semiarid regions of the United States, Canada, and Mexico and the only effective control is genetic resistance. Our objective was to determine if dry bean landrace G122, which lacks the Bct gene for resistance to CTV, contains novel resistance to the virus. Two populations, GT-A and GT-B, consisting of 98 F5:7 recombinant inbred lines (RILs) in total were derived from a cross between G122 and the susceptible variety Taylor Horticultural and evaluated for phenotypic response to natural CTV field infection. Genetic analyses revealed random amplified polymorphism DNA (RAPD) markers associated with a major-effect quantitative trait loci (QTL) from G122 which exhibited stable expression across 3 years in both populations. Phenotypic variation explained by the QTL in GT-A (37.6%) was greater than in GT-B (20.4%). RAPD marker Q14.973 was converted to a sequence-characterized amplified region (SCAR) and designated SQ14.973. The SCAR was used to locate the QTL on linkage group 6 of the Phaseolus core map. A survey of 74 common bean cultivars and breeding lines revealed SQ14.973 would be widely useful for marker-assisted selection of the QTL. An additional minor-effect QTL from G122 was detected on linkage group 7. G122 was determined to possess novel resistance to CTV conditioned by at least two genes, one with major the other minor effect.

scholarly journals Quantitative trait loci for exercise training responses in FVB/NJ and C57BL/6J mice

2009 ◽  
Vol 40 (1) ◽  
pp. 15-22 ◽  
Author(s):  
Michael P. Massett ◽  
Ruzong Fan ◽  
Bradford C. Berk
Keyword(s):  
Quantitative Trait Loci ◽  
Exercise Training ◽  
Exercise Capacity ◽  
Quantitative Trait ◽  
Performance Test ◽  
Treadmill Running ◽  
Nucleotide Polymorphisms ◽  
Genomewide Linkage ◽  
Trait Loci ◽  
And Training

The genetic factors determining the magnitude of the response to exercise training are poorly understood. The aim of this study was to identify quantitative trait loci (QTL) associated with adaptation to exercise training in a cross between FVB/NJ (FVB) and C57BL/6J (B6) mice. Mice completed an exercise performance test before and after a 4-wk treadmill running program, and changes in exercise capacity, expressed as work (kg·m), were calculated. Changes in work in F2 mice averaged 1.51 ± 0.08 kg·m (94.3 ± 7.3%), with a range of −1.67 to +4.55 kg·m. All F2 mice ( n = 188) were genotyped at 20-cM intervals with 103 single nucleotide polymorphisms (SNPs), and genomewide linkage scans were performed for pretraining, posttraining, and change in work. Significant QTL for pretraining work were located on chromosomes 14 at 4.0 cM [3.72 logarithm of odds (LOD)] and 19 at 34.4 cM (3.63 LOD). For posttraining work significant QTL were located on chromosomes 3 at 60 cM (4.66 LOD) and 14 at 26 cM (4.99 LOD). Suggestive QTL for changes in work were found on chromosomes 11 at 44.6 cM (2.30 LOD) and 14 at 36 cM (2.25 LOD). When pretraining work was used as a covariate, a potential QTL for change in work was identified on chromosome 6 at 68 cM (3.56 LOD). These data indicate that one or more QTL determine exercise capacity and training responses in mice. Furthermore, these data suggest that the genes that determine pretraining work and training responses may differ.

A random model approach to interval mapping of quantitative trait loci.

Genetics ◽  
1995 ◽  
Vol 141 (3) ◽  
pp. 1189-1197 ◽  
Author(s):  
S Xu ◽  
W R Atchley
Keyword(s):  
Quantitative Trait Loci ◽  
Quantitative Trait ◽  
Fixed Effects ◽  
Interval Mapping ◽  
Random Model ◽  
Likelihood Method ◽  
Mapping Procedure ◽  
Trait Loci ◽  
Outbred Populations ◽  
Model Approach

Abstract Mapping quantitative trait loci in outbred populations is important because many populations of organisms are noninbred. Unfortunately, information about the genetic architecture of the trait may not be available in outbred populations. Thus, the allelic effects of genes can not be estimated with ease. In addition, under linkage equilibrium, marker genotypes provide no information about the genotype of a QTL (our terminology for a single quantitative trait locus is QTL while multiple loci are referred to as QTLs). To circumvent this problem, an interval mapping procedure based on a random model approach is described. Under a random model, instead of estimating the effects, segregating variances of QTLs are estimated by a maximum likelihood method. Estimation of the variance component of a QTL depends on the proportion of genes identical-by-descent (IBD) shared by relatives at the locus, which is predicted by the IBD of two markers flanking the QTL. The marker IBD shared by two relatives are inferred from the observed marker genotypes. The procedure offers an advantage over the regression interval mapping in terms of high power and small estimation errors and provides flexibility for large sibships, irregular pedigree relationships and incorporation of common environmental and fixed effects.

scholarly journals IDENTIFICACIÓN DE QTLs ASOCIADOS A CARACTERES DE ARQUITECTURA VEGETAL EN YUCA (Manihot esculenta)

2015 ◽  
Vol 21 (1) ◽  
Author(s):  
Camilo López ◽  
Ruben Eduardo Mora Moreno ◽  
Johana Carolina Soto
Keyword(s):  
Quantitative Trait Loci ◽  
Leaf Area ◽  
Plant Height ◽  
Quantitative Trait ◽  
Manihot Esculenta ◽  
Root Weight ◽  
Nucleotide Polymorphisms ◽  
Single Nucleotide ◽  
Trait Loci ◽  
Number Of Shoots

<p class="p1"><strong>RESUMEN</strong></p><p class="p2">La yuca (<em>Manihot esculenta</em>) es el cuarto cultivo en importancia a nivel mundial como fuente de calorías para la población humana después del arroz, el azúcar y el maíz, posicionándose por esta razón como un cultivo primordial para la seguridad alimentaria. Su arquitectura ha sido considerada como un factor clave que subyace a la fisiología del rendimiento, relacionando características morfológicas con productividad. En este trabajo se evaluaron diferentes características de arquitectura vegetal en yuca. Los caracteres fueron evaluados en una población F1 compuesta por 133 hermanos completos (familia K) sembrados en dos lugares biogeográficamente diferentes: La Vega (Cundinamarca) y Arauca (Arauca) en Colombia. Las características evaluadas relacionadas con la arquitectura vegetal fueron altura de la planta (AT), número de brotes (NB), longitud entrenudos (LE), número de raíces (NR), peso de raíces (PR), pigmentación del peciolo (PP), área de la hoja (AH) y tipo de hoja (TH). A partir de los datos obtenidos y empleando un mapa genético de alta densidad basado en SNPs (Single Nucleotide Polymorphisms) se llevó a cabo un análisis de QTLs (Quantitative Trait Loci). Se lograron identificar tres QTLs para La Vega asociados con los caracteres altura total, número de brotes y área de la hoja. Para Arauca se detectaron tres QTLs asociados con altura total, longitud de entrenudos y número de brotes. Los QTLs se distribuyeron en cuatro grupos de ligamiento y explicaron entre 18,93 y 41,92 % de la variación genética.</p><p class="p1"><strong>ABSTRACT</strong></p><p class="p2">Cassava (<em>Manihot esculenta</em>) is the fourth most important crop worldwide as a source of calories for the human population after rice, sugar and corn and therefore it is considered as a staple crop. Cassava’s architecture has been considered as a key factor underlying the physiology of yield, relating morphological traits with productivity. In this work different characteristics of plant architecture were evaluated in a cassava F1 population composed by 133 complete siblings (family K) planted in two biogeographically different zones: La Vega (Cundinamarca) and Arauca (Arauca) in Colombia. The characteristics evaluated related to the vegetal architecture were plant height (AT), number of shoots (NB), internodes length (LE), number of roots (NR), root weight (PR), petiole pigmentation (PP), leaf area (AH) and leaf type (TH). From the data obtained and using a SNP- (Single Nucleotide Polymorphism) high-density genetic map a QTLs analysis (Quantitative Trait Loci) was carried out. It was possible to identify three QTLs for La Vega associated with characters plant height, internodes length and leaf area. From the Arauca’s dataset, three QTLs were detected associated with plant height, number of shoots and internodes length. The QTLs were distributed into four linkage groups and explained between 18.93 and 41.92 % of genetic variation.</p><p class="p2"> </p>

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