scholarly journals Genomic analysis of family data reveals additional genetic effects on intelligence and personality

2017 ◽  
Author(s):  
W. David Hill ◽  
Ruben C. Arslan ◽  
Charley Xia ◽  
Michelle Luciano ◽  
Carmen Amador ◽  
...  

AbstractPedigree-based analyses of intelligence have reported that genetic differences account for 50-80% of the phenotypic variation. For personality traits these effects are smaller, with 34-48% of the variance being explained by genetic differences. However, molecular genetic studies using unrelated individuals typically report a heritability estimate of around 30% for intelligence and between 0% and 15% for personality variables. Pedigree-based estimates and molecular genetic estimates may differ because current genotyping platforms are poor at tagging causal variants, variants with low minor allele frequency, copy number variants, and structural variants. Using ∼20 000 individuals in the Generation Scotland family cohort genotyped for ∼700 000 single nucleotide polymorphisms (SNPs), we exploit the high levels of linkage disequilibrium (LD) found in members of the same family to quantify the total effect of genetic variants that are not tagged in GWASs of unrelated individuals. In our models, genetic variants in low LD with genotyped SNPs explain over half of the genetic variance in intelligence, education, and neuroticism. By capturing these additional genetic effects our models closely approximate the heritability estimates from twin studies for intelligence and education, but not for neuroticism and extraversion. We then replicated our finding using imputed molecular genetic data from unrelated individuals to show that ∼50% of differences in intelligence, and ∼40% of the differences in education, can be explained by genetic effects when a larger number of rare SNPs are included. From an evolutionary genetic perspective, a substantial contribution of rare genetic variants to individual differences in intelligence and education is consistent with mutation-selection balance.

2021 ◽  
pp. 164-186
Author(s):  
Benjamin B. Lahey

This chapter summarizes the basic biology of inheritance, including chromosomes, genes, nucleotides, genotype, and gene expression. It uses these concepts and the logic of studies of the two kinds of twins—monozygotic and dizygotic—to define the concept of heritability as the proportion of differences on the dimension among people in the population that is attributable to genetic factors. The genetic variance in the phenotypes of psychological problems, such as depression, is never encoded in a single allele or genetic variant. Rather, every dimension of psychological problems is polygenic, meaning that many genetic variants have very small genetic influences on each dimension of psychological problems that must be combined to meaningfully measure the genetic component of risk at the molecular level. Often, single variations in individual nucleotides—the molecules arranged on DNA that serve as the letters of the genetic code—known as single nucleotide polymorphisms are summed to quantify the molecular genetic risk in a polygenic risk score. The nonspecific genetic influences at the top of the hierarchy of genetic influences result from some genetic variants being pleiotropic in the sense of directly or indirectly influencing essentially all dimensions of psychological problems. Identifying the specific genetic and environmental influences on dimensions of psychological problems at each level of the hierarchy is complicated because they operate together through the crucially important gene–environment correlations and interactions described in this chapter.


2021 ◽  
Vol 12 ◽  
Author(s):  
Asset Daniyarov ◽  
Askhat Molkenov ◽  
Saule Rakhimova ◽  
Ainur Akhmetova ◽  
Dauren Yerezhepov ◽  
...  

Tuberculosis (TB) is an infectious disease that remains an essential public health problem in many countries. Despite decreasing numbers of new cases worldwide, the incidence of antibiotic-resistant forms (multidrug resistant and extensively drug-resistant) of TB is increasing. Next-generation sequencing technologies provide a high-throughput approach to identify known and novel potential genetic variants that are associated with drug resistance in Mycobacterium tuberculosis (Mtb). There are limited reports and data related to whole-genome characteristics of drug-resistant Mtb strains circulating in Kazakhstan. Here, we report whole-genome sequencing and analysis results of eight multidrug-resistant strains collected from TB patients in Kazakhstan. Genotyping and validation of all strains by MIRU-VNTR and spoligotyping methodologies revealed that these strains belong to the Beijing family. The spectrum of specific and potentially novel genomic variants (single-nucleotide polymorphisms, insertions, and deletions) related to drug resistance was identified and annotated. ResFinder, CARD, and CASTB antibiotic resistance databases were used for the characterization of genetic variants in genes associated with drug resistance. Our results provide reference data and genomic profiles of multidrug-resistant isolates for further comparative studies and investigations of genetic patterns in drug-resistant Mtb strains.


Author(s):  
Péter P. Ujma ◽  
Nóra Eszlári ◽  
András Millinghoffer ◽  
Bence Bruncsics ◽  
Péter Petschner ◽  
...  

AbstractEducational attainment is a substantially heritable trait, and it has recently been linked to specific genetic variants by genome-wide association studies (GWASs). However, the effects of such genetic variants are expected to vary across environments, including countries and historical eras. We used polygenic scores (PGSs) to assess molecular genetic effects on educational attainment in Hungary, a country in the Central Eastern European region where behavioral genetic studies are in general scarce and molecular genetic studies of educational attainment have not been previously published. We found that the PGS is significantly associated with highest educational level attained as well as the number of years in education in a sample of Hungarian volunteers (N=829). In an English (N=976) comparison sample with identical measurement protocols the same PGS had a stronger association with educational level, but not with years in education. In line with previous Estonian findings, we found higher PGS effect sizes in Hungarian, but not in English participants who attended higher education after the fall of Communism, although we lacked statistical power for this effect to reach significance. Our results provide evidence that polygenic scores for educational attainment are valid in diverse European populations.


2020 ◽  
Vol 36 (6) ◽  
pp. 49-54
Author(s):  
A.A. Nalbandyan ◽  
T.P. Fedulova ◽  
I.V. Cherepukhina ◽  
T.I. Kryukova ◽  
N.R. Mikheeva ◽  
...  

The flowering time control gene of various sugar beet plants has been studied. The BTC1 gene is a regulator for the suppressor (flowering time 1) and inducer (flowering time 2) genes of this physiological process. The F9/R9 primer pair was used for polymerase chain reaction; these primers are specific to the BTC1 gene region containing exon 9, as well as intron and exon 10. For the first time, nucleotide substitutions in exon 10 of BTC1 gene were identified in bolting sensitive samples (HF1 and BF1), which led to a change in the amino acid composition of the coded polypeptide chain. Based on the results of bioinformatic analysis, it can be assumed that certain nucleotide polymorphisms in the BTC1 gene may determine with a high probability the predisposition of sugar beet genotypes to early flowering. The use of the Geneious Prime tool for the analysis of the BTC1 gene sequences may allow the culling of genotypes prone to early flowering at early stages of selection. sugar beet, flowering gene, BTC1, genetic polymorphism, PCR, molecular genetic markers, selection


2016 ◽  
Vol 3 (2) ◽  
Author(s):  
SHAILESH CHAND GAUTAM ◽  
MP Chauhan

Line × tester analysis of twenty lines and three testers of Indian mustard (Brassica juncea L. Czern & Coss.) cultivars were used to estimate general combining ability (GCA), specific combining ability (SCA) effects, high parent heterosis and narrow-sense heritability estimate for plant height, yield components and seed yield. Significant variance of line x tester for the traits like pods per plant and seed yield indicating non additive genetic effects have important role for controlling these traits. Significant mean squares of parents v/s crosses which are indicating significant average heterosis were also significant for all the traits except seeds per pod. High narrow-sense heritability estimates for all the traits except seeds per pod exhibited the prime importance of additive genetic effects for these traits except seeds per pod. Most of the crosses with negative SCA effect for plant height had at least one parent with significant negative or negative GCA effect for this trait. For most of the traits except pods per plant, the efficiency of high parent heterosis effect was more than SCA effect for determining superior cross combinations.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sabrina Samad Shoily ◽  
Tamim Ahsan ◽  
Kaniz Fatema ◽  
Abu Ashfaqur Sajib

AbstractDiabetes mellitus is a complex and heterogeneous metabolic disorder which is often pre- or post-existent with complications such as cardiovascular disease, hypertension, inflammation, chronic kidney disease, diabetic retino- and nephropathies. However, the frequencies of these co-morbidities vary among individuals and across populations. It is, therefore, not unlikely that certain genetic variants might commonly contribute to these conditions. Here, we identified four single nucleotide polymorphisms (rs5186, rs1800795, rs1799983 and rs1800629 in AGTR1, IL6, NOS3 and TNFA genes, respectively) to be commonly associated with each of these conditions. We explored their possible interplay in diabetes and associated complications. The variant allele and haplotype frequencies at these polymorphic loci vary among different super-populations (African, European, admixed Americans, South and East Asians). The variant alleles are particularly highly prevalent in different European and admixed American populations. Differential distribution of these variants in different ethnic groups suggests that certain drugs might be more effective in selective populations rather than all. Therefore, population specific genetic architectures should be considered before considering a drug for these conditions.


2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Youguo Hao ◽  
Lijun Xie ◽  
Jing Xia ◽  
Zhen Liu ◽  
Baoxiu Yang ◽  
...  

Abstract Background Rheumatoid Arthritis (RA) is a chronic inflammatory condition characterized by autoantibodies development and an elevated spectrum of pro-inflammatory cytokines. Previous reports highlighted a relationship between IL-21and the pathogenesis of RA. Although elevated IL-21 levels have been reported in RA patients, the association of common IL-21 genetic variants with a predisposition to RA development in the Chinese population lacks. Materials and methods Five hundred and fourteen Chinese subjects (healthy controls: 303 and rheumatoid arthritis patients: 211) were enrolled in the study. Clinical data of patients were collected from medical records, and patients were treated as per the guidelines. Common single nucleotide polymorphisms in the IL-21 gene (rs907715, rs2221903, rs2055979 and rs6822844) were genotyped by TaqMan SNPs genotyping method. IL-21 level in plasma of RA patients and healthy subjects was measured by ELISA. Results The plasma level of IL-21 was significantly higher in subjects with rheumatoid arthritis relative to healthy controls (p < 0.0001). A positive correlation was observed between IL-21 level and DAS28 score, indicating the association of the cytokine with the worsening of the disease (Spearman r = 0.61, p < 0.0001). The prevalence of AA genotype (rs2055979) was significantly higher in RA subjects than in the controls (p < 0.0001, χ2 = 34.73, OR = 4.34, 95% CI = 2.623 to 7.219). Furthermore, elevated plasma IL-21 was observed in the rs2055979-AA genotype compared to CC type (p < 0.0001). Conclusion IL-21 plays a crucial function in rheumatoid arthritis pathogenesis. IL-21 rs2055979 polymorphism is associated with IL-21 plasma levels and is predisposed to RA development in the Chinese population.


2020 ◽  
Vol 10 (1) ◽  
pp. 2 ◽  
Author(s):  
Laith N. AL-Eitan ◽  
Doaa M. Rababa’h ◽  
Nancy M. Hakooz ◽  
Mansour A. Alghamdi ◽  
Rana B. Dajani

Several genetic variants have been identified that cause variation among different populations and even within individuals of a similar descent. This leads to interindividual variations in the optimal dose of the drug that is required to sustain the treatment efficiency. In this study, 56 single nucleotide polymorphisms (SNPs) within several pharmacogenes were analyzed in 128 unrelated subjects from a genetically isolated group of Circassian people living in Jordan. We also compared these variant distributions to other ethnic groups that are available at two databases (Genome 1000 and eXAC). Our results revealed that the distribution of allele frequencies within genes among Circassians in Jordan showed similarities and disparities when compared to other populations. This study provides a powerful base for clinically relevant SNPs to enhance medical research and future pharmacogenomic studies. Rare variants detected in isolated populations can significantly guide to novel loci involved in the development of clinically relevant traits.


2016 ◽  
Vol 46 (10) ◽  
pp. 2059-2069 ◽  
Author(s):  
L. C. Bidwell ◽  
R. H. C. Palmer ◽  
L. Brick ◽  
J. E. McGeary ◽  
V. S. Knopik

BackgroundHeritability estimates from twin studies of the multi-faceted phenotype of nicotine dependence (ND) range from moderate to high (31–60%), but vary substantially based on the specific ND-related construct examined. The current study estimated the aggregate role of common genetic variants on key ND constructs.MethodGenomic-relationship-matrix restricted maximum likelihood (GREML) was used to decompose phenotypic variance across multiple ND indices using 796 125 polymorphisms from 2346 unrelated ‘lifetime ever smokers’ of European ancestry. Measures included DSM-IV ND and Fagerström Test for Nicotine Dependence (FTND) summary measures and constituent constructs (e.g. withdrawal severity, tolerance, heaviness of smoking and time spent smoking). Exploratory and confirmatory factor models were used to describe the covariance structure across ND measures; resulting factor(s) were the subject(s) of GREML analyses.ResultsFactor models indicated highly correlated DSM-IV and FTND factors for ND (0.545, 95% confidence interval 0.50–0.60) that could be represented as a higher-order factor (NIC DEP). Additive genetic influence on NIC DEP was 33% (s.e. = 0.14, p = 0.009). Post-hoc analyses indicated moderate genetic effects on the DSM-IV (34%, s.e. = 0.14, p = 0.008) and FTND (26%, s.e. = 0.14, p = 0.032) factors, both of which were influenced by the same genetic effects (rG-SNP = 1.00, s.e. = 0.09, p < 0.00001).ConclusionsOverall, common single nucleotide polymorphisms accounted for a large proportion of the genetic influences on ND-related phenotypes that have been observed in twin studies. Genetic contributions across distinct ND scales were largely influenced by shared genetic factors.


Cephalalgia ◽  
2016 ◽  
Vol 36 (11) ◽  
pp. 1028-1037 ◽  
Author(s):  
Jong-Ling Fuh ◽  
Ming-Yi Chung ◽  
Shu-Chih Yao ◽  
Ping-Kun Chen ◽  
Yi-Chu Liao ◽  
...  

Objective Several genetic variants have been found to increase the risk of restless legs syndrome (RLS). The aim of the present study was to determine if these genetic variants were also associated with the comorbidity of RLS and migraine in patients. Methods Thirteen single-nucleotide polymorphisms (SNPs) at six RLS risk loci ( MEIS1, BTBD9, MAP2K5, PTPRD, TOX3, and an intergenic region on chromosome 2p14) were genotyped in 211 migraine patients with RLS and 781 migraine patients without RLS. Association analyses were performed for the overall cohort, as well as for the subgroups of patients who experienced migraines with and without aura and episodic migraines (EMs) vs. chronic migraines (CMs). In order to verify which genetic markers were potentially related to the incidence of RLS in migraine patients, multivariate regression analyses were also performed. Results Among the six tested loci, only MEIS1 was significantly associated with RLS. The most significant SNP of MEIS1, rs2300478, increased the risk of RLS by 1.42-fold in the overall cohort ( p = 0.0047). In the subgroup analyses, MEIS1 augmented the risk of RLS only in the patients who experienced EMs (odds ratio (OR) = 1.99, p = 0.0004) and not those experiencing CMs. Multivariate regression analyses further showed that rs2300478 in MEIS1 (OR = 1.39, p = 0.018), a CM diagnosis (OR = 1.52, p = 0.022), and depression (OR = 1.86, p = 0.005) were independent predictors of RLS in migraine. Conclusions MEIS1 variants were associated with an increased risk of RLS in migraine patients. It is possible that an imbalance in iron homeostasis and the dopaminergic system may represent a link between RLS incidence and migraines.


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