Project description:Japanese cedar (Cryptomeria japonica) is an allogamous coniferous species that relies on wind-mediated pollen and seed dispersal, and it is one of the most important forestry tree species in Japan. For accelerating breeding, we collected massive SNPs based on ESTs from several organs using NGS, and thus carried out QTL, GWAS and GS based on high-density linkage maps.
Project description:Japanese cedar (Cryptomeria japonica) is an allogamous coniferous species that relies on wind-mediated pollen and seed dispersal, and it is one of the most important forestry tree species in Japan. For accelerating breeding, we collected massive SNPs based on ESTs from several organs using NGS, and thus carried out QTL, GWAS and GS based on high-density linkage maps.
Project description:Digital dermatitis (DD) causes lameness in dairy cattle. To detect quantitative trait loci (QTL) associated with DD, genome-wide association studies (GWAS) were performed using high density single nucleotide polymorphism (SNP) genotypes and binary case/control, quantitative (average number of FW per hoof trimming record), and recurrent (cases with 2 DD episodes vs. controls) phenotypes from cows across four dairies (controls n = 129 vs. FW n = 85). Linear mixed model (LMM) and random forest (RF) approaches identified top SNPs, which were used as predictors in Bayesian regression models to assess SNP predictive value. The LMM and RF analyses identified a QTL on BTA1 for the binary phenotype and on BTA2 for the quantitative phenotype. The binary and recurrent LMM GWASs also detected a QTL on BTA2 that was at a different position than the QTL from the quantitative phenotype analysis. The QTL on BTA1 lacked apparent candidate genes, whereas both QTL on BTA2 included genes associated with immune response and wound healing. Although larger sample sizes are necessary to reaffirm these small effect loci amidst a strong environmental effect, the sample cohort used in this study was sufficient for estimating SNP effects with high predictive value.
2020-12-07 | GSE159157 | GEO
Project description:RAD-seq of 207 individuals of Primulina for QTL mapping
Project description:Marker-assisted selective breeding of fish with higher levels of resistance towards specific pathogens has shown successful, but. However, the impact of host genotype on multiple pathogen infections are is still poorly investigated. This study examined the resistance in rainbow trout (Oncorhynchus mykis) towards infection with the eye fluke Diplostomum pseudospathaceum. We used genetically selected rainbow trout, carrying SNPs associated with resistance towards the parasitic ciliate Ichthyophthirius multifiliis, and exposed the fish to eye fluke cercariae. We showed that fish partly resistant to I. multifiliis were more susceptible to eye fluke invasion. Expression The expression of immune relevant genes (encoding innate and adaptive factors) was also affected as these genotypes responded less strongly to a secondary fluke infection. The complexity of genome architecture in disease resistance towards multiple pathogens is discussed. A total of 200 rainbow trout (body weight 14.3-17.7 g, body length 10.2-11.5 cm) were used for the study. Two groups of rainbow trout with high (QTL fish) and low (non-QTL fish) frequency of SNPs associated with I. multifiliis resistance, were hatched from eyed eggs at the disease free recirculated Bornholm Salmon Hatchery, Nexø, Denmark and subsequently reared to the fingerling stage. For this purpose, the first group (QTL-fish) was produced by using sperm from three male genotyped parents carrying SNPs AX-89947214 (Omy17) and AX-89960822 (Omy16), and the other group (non-QTL fish) was produced by using sperm from three other male parents negative for these SNPs. In both cases, sperm was used to fertilize a common pool of eggs stripped from a total of 30 outbred females. Processes of hatching and subsequent rearing of fry to the fingerling stage did not differ between groups of QTL fish and non-QTL fish. From each group (QTL and non-QTL fish) we randomly gathered 100 rainbow trout and transported them (3 h duration) from the hatchery to the infection facility at the University of Copenhagen. Fish were then accommodated and acclimatized 14 d in identical aerated glass tanks with internal biofilters (25 fish per 60 L water, total tank volume 80 L), which were placed in a temperature temperature-controlled room (water temperature constant at 12°C, pH 7.6). We used 30% water change per day to maintain ammonia levels below 0.25. Fish were fed by pelleted feed (1% of fish biomass per day). All fish were genotyped with respect to the two relevant QTLs, one on chomosome 16 and one on chromosome 17. Fish being double heterozugous were excluded from qPCR analysis.