Prediction of susceptible biomarkers for end stage renal disease among North Indians.
Nephrology (Carlton). 2015 Sep 30;
Authors: Prakash S, Sarangi AN, Tripathi G, Sharma RK, Agrawal S
AIM: Involvement of pro-inflammatory genes has been correlated with basic kidney diseases and end stage renal disease (ESRD). However, results at odds were often noted from such independent association studies. This study proposes a genome wide analysis approach to predict ESRD risk associated genes.
METHODS: We included 42 single nucleotide polymorphisms (SNPs) showing association among north Indian ESRD cases and controls. ESRD cases comprised of CGN, CIN, HTN and PKD. Genotyping data obtained from our prior published reports were compared with GWAS SNPs retrieved from HapMap and GWASCentral databases using R-statistical package SNPAssoc. Linkage disequilibrium (LD), gene-gene interaction, classification and regression tree (CART) and pathway analysis were carried out in the present study supplemented with IL-6 and TNF-α levels estimation using ELISA.
RESULTS: Comparison of genotyping data with GWAS SNPs revealed significant associations for IL1-RN, IL-6, MTHFR, TNF-α and CCR3 genes with ESRD. Nine SNPs were commonly associated with CGN, CIN, HTN, PKD and ESRD. LD (D = 0.9) and gene-gene interaction (p = 0.0002) analyses revealed significant associations for IL-6 and TNF-α genes. In a consistent manner CART analysis and functional analysis servers predict predisposing effects for TNF-α and IL-6 with ESRD. Finally higher body circulating levels were observed for mutant TNF-α and IL-6 alleles among ESRD.
CONCLUSION: The study indicates significance for IL-6 and TNF-α gene with basic kidney diseases and ESRD. Extensive statistical tests, pathway analysis and functional assays also reflect attenuated level of significance for these SNPs. In future these may be brought from bench side to clinical practice as diagnostic biomarkers upon external and prospective replication and confirmation among other cohorts.
PMID: 26421528 [PubMed - as supplied by publisher]
Fine-Mapping the Wheat Snn1 Locus Conferring Sensitivity to the Parastagonospora nodorum Necrotrophic Effector SnTox1 Using an Eight Founder Multiparent Advanced Generation Inter-Cross Population.
G3 (Bethesda). 2015 Sep 28;
Authors: Cockram J, Scuderi A, Barber T, Furuki E, Gardner KA, Gosman N, Kowalczyk R, Phan HP, Rose GA, Tan KC, Oliver RP, Mackay IJ
The necrotrophic fungus Parastagonospora nodorum is an important pathogen of one of the world's most economically important cereal crops, wheat (Triticum aestivum L.). P. nodorum produces necrotrophic protein effectors that mediate host cell death, providing nutrients for continuation of the infection process. The recent discovery of pathogen effectors has revolutionised disease resistance breeding for necrotrophic diseases in crop species, allowing often complex genetic resistance mechanisms to be broken down into constituent parts. To date, three effectors have been identified in P. nodorum. Here we use the effector, SnTox1, to screen 642 progeny from an eight parent multiparent advanced generation inter-cross (MAGIC) population, genotyped with a 90,000 feature single nucleotide polymorphism array. The MAGIC founders showed a range of sensitivity to SnTox1, with transgressive segregation evident in the progeny. SnTox1 sensitivity showed high heritability, with quantitative trait locus analyses fine-mapping the Snn1 locus to the short arm of chromosome 1B. In addition, a previously undescribed SnTox1 sensitivity locus was identified on the long arm of chromosome 5A, termed here QSnn.niab-5A.1. The peak SNP for the Snn1 locus was converted to the KASP genotyping platform, providing breeders and researchers a simple and cheap diagnostic marker for allelic state at Snn1.
PMID: 26416667 [PubMed - as supplied by publisher]
A GWAS Study on Liver Function Test Using eMERGE Network Participants.
PLoS One. 2015;10(9):e0138677
Authors: Namjou B, Marsolo K, Lingren T, Ritchie MD, Verma SS, Cobb BL, Perry C, Kitchner TE, Brilliant MH, Peissig PL, Borthwick KM, Williams MS, Grafton J, Jarvik GP, Holm IA, Harley JB
INTRODUCTION: Liver enzyme levels and total serum bilirubin are under genetic control and in recent years genome-wide population-based association studies have identified different susceptibility loci for these traits. We conducted a genome-wide association study in European ancestry participants from the Electronic Medical Records and Genomics (eMERGE) Network dataset of patient medical records with available genotyping data in order to identify genetic contributors to variability in serum bilirubin levels and other liver function tests and to compare the effects between adult and pediatric populations.
METHODS: The process of whole genome imputation of eMERGE samples with standard quality control measures have been described previously. After removing missing data and outliers based on principal components (PC) analyses, 3294 samples from European ancestry were used for the GWAS study. The association between each single nucleotide polymorphism (SNP) and total serum bilirubin and other liver function tests was tested using linear regression, adjusting for age, gender, site, platform and ancestry principal components (PC).
RESULTS: Consistent with previous results, a strong association signal has been detected for UGT1A gene cluster (best SNP rs887829, beta = 0.15, p = 1.30x10-118) for total serum bilirubin level. Indeed, in this region more than 176 SNPs (or indels) had p<10-8 spanning 150Kb on the long arm of chromosome 2q37.1. In addition, we found a similar level of magnitude in a pediatric group (p = 8.26x10-47, beta = 0.17). Further imputation using sequencing data as a reference panel revealed association of other markers including known TA7 repeat indels (rs8175347) (p = 9.78x10-117) and rs111741722 (p = 5.41x10-119) which were in proxy (r2 = 0.99) with rs887829. Among rare variants, two Asian subjects homozygous for coding SNP rs4148323 (G71R) were identified. Additional known effects for total serum bilirubin were also confirmed including organic anion transporters SLCO1B1-SLCO1B3, TDRP and ZMYND8 at FDR<0.05 with no gene-gene interaction effects. Phenome-wide association studies (PheWAS) suggest a protective effect of TA7 repeat against cerebrovascular disease in an adult cohort (OR = 0.75, p = 0.0008). Among other liver function tests, we also confirmed the previous effect of the ABO blood group locus for variation in serum alkaline phosphatase (rs579459, p = 9.44x10-15).
CONCLUSIONS: Taken together, our data present interesting findings with strong confirmation of previous effects by simply using the eMERGE electronic health record phenotyping. In addition, our findings indicate that similar to the adult population, the UGT1A1 is the main locus responsible for normal variation of serum bilirubin in pediatric populations.
PMID: 26413716 [PubMed - as supplied by publisher]
Estimating genomic heritabilities at the level of family-pool samples of perennial ryegrass using genotyping-by-sequencing.
Theor Appl Genet. 2015 Sep 25;
Authors: Ashraf BH, Byrne S, Fé D, Czaban A, Asp T, Pedersen MG, Lenk I, Roulund N, Didion T, Jensen CS, Jensen J, Janss LL
KEYMESSAGE: By using the genotyping-by-sequencing method, it is feasible to characterize genomic relationships directly at the level of family pools and to estimate genomic heritabilities from phenotypes scored on family-pools in outbreeding species. Genotyping-by-sequencing (GBS) has recently become a promising approach for characterizing plant genetic diversity on a genome-wide scale. We use GBS to extend the concept of heritability beyond individuals by genotyping family-pool samples by GBS and computing genomic relationship matrices (GRMs) and genomic heritabilities directly at the level of family-pools from pool-frequencies obtained by sequencing. The concept is of interest for species where breeding and phenotyping is not done at the individual level but operates uniquely at the level of (multi-parent) families. As an example we demonstrate the approach using a set of 990 two-parent F2 families of perennial ryegrass (Lolium Perenne). The families were phenotyped as a family-unit in field plots for heading date and crown rust resistance. A total of 728 K single nucleotide polymorphism (SNP) variants were available and were divided in groups of different sequencing depths. GRMs based on GBS data showed diagonal values biased upwards at low sequencing depth, while off-diagonals were little affected by the sequencing depth. Using variants with high sequencing depth, genomic heritability for crown rust resistance was 0.33, and for heading date 0.22, and these genomic heritabilities were biased downwards when using variants with lower sequencing depth. Broad sense heritabilities were 0.61 and 0.66, respectively. Underestimation of genomic heritability at lower sequencing depth was confirmed with simulated data. We conclude that it is feasible to use GBS to describe relationships between family-pools and to estimate genomic heritability directly at the level of F2 family-pool samples, but estimates are biased at low sequencing depth.
PMID: 26407618 [PubMed - as supplied by publisher]