Attack of the dark clones the genetics of reproductive and color traits of South African honey bees (Apis mellifera spp.)

The traits of two subspecies of western honey bees, Apis mellifera scutellata and A.m. capensis, endemic to the Republic of South Africa (RSA), are of biological and commercial relevance. Nevertheless, the genetic basis of important phenotypes found in these subspecies remains poorly understood. We performed a genome wide association study on three traits of biological relevance in 234 A.m. capensis, 73 A.m. scutellata and 158 hybrid individuals. Thirteen markers were significantly associated to at least one trait (P ≤ 4.28 × 10−6): one for ovariole number, four for scutellar plate and eight for tergite color. We discovered two possible causative variants associated to the respective phenotypes: a deletion in GB46429 or Ebony (NC_007070.3:g.14101325G>del) (R69Efs*85) and a nonsense on GB54634 (NC_007076.3:g.4492792A>G;p.Tyr128*) causing a premature stop, substantially shortening the predicted protein. The mutant genotypes are significantly associated to phenotypes in A.m. capensis. Loss-of-function of Ebony can cause accumulation of circulating dopamine, and increased dopamine levels correlate to ovary development in queenless workers and pheromone production. Allelic association (P = 1.824 x 10−5) of NC_007076.3:g.4492792A>G;p.Tyr128* to ovariole number warrants further investigation into function and expression of the GB54634 gene. Our results highlight genetic components of relevant production/conservation behavioral phenotypes in honey bees.

The genetic susceptibility profile of type 2 diabetes and reflection of its possible role related to reproductive dysfunctions in the southern Indian population of Hyderabad

Background The genetic association studies of type 2 diabetes mellitus (T2DM) hitherto undertaken among the Indian populations are grossly inadequate representation of the ethnic and geographic heterogeneity of the country. In view of this and due to the inconsistent nature of the results of genetic association studies, it would be prudent to undertake large scale studies in different regions of India considering wide spectrum of variants from the relevant pathophysiological pathways. Given the reproductive dysfunctions associated with T2DM, it would be also interesting to explore if some of the reproductive pathway genes are associated with T2DM. The present study is an attempt to examine these aspects in the southern Indian population of Hyderabad. Methods A prioritized panel of 92 SNPs from a large number of metabolic and reproductive pathway genes was genotyped on 500 cases and 500 controls, matched for ethnicity, age and BMI, using AGENA MassARRAYiPLEX™ platform. Results The allelic association results suggested 14 SNPs to be significantly associated with T2DM at P ≤ 0.05 and seven of those—rs2241766-G (ADIPOQ), rs6494730-T (FEM1B), rs1799817-A and rs2059806-T (INSR), rs11745088-C (FST), rs9939609-A and rs9940128-A (FTO)—remained highly significant even after correction for multiple testing. A great majority of the significant SNPs were risk in nature. The ROC analysis of the risk scores of the significant SNPs yielded an area under curve of 0.787, suggesting substantial power of our study to confer these genetic variants as predictors of risk for T2DM. Conclusions The associated SNPs of this study are known to be specifically related to insulin signaling, fatty acid metabolism and reproductive pathway genes and possibly suggesting the role of overlapping phenotypic features of insulin resistance, obesity and reproductive dysfunctions inherent in the development of diabetes. Large scale studies involving gender specific approach may be required in order to identify the precise nature of population and gender specific risk profiles for different populations, which might be somewhat distinct.

Local Ancestry Adjusted Allelic Association Analysis Robustly Captures Tuberculosis Susceptibility Loci

Pulmonary tuberculosis (TB), caused by Mycobacterium tuberculosis, is a complex disease. The risk of developing active TB is in part determined by host genetic factors. Most genetic studies investigating TB susceptibility fail to replicate association signals particularly across diverse populations. South African populations arose because of multi-wave genetic admixture from the indigenous KhoeSan, Bantu-speaking Africans, Europeans, Southeast Asian-and East Asian populations. This has led to complex genetic admixture with heterogenous patterns of linkage disequilibrium and associated traits. As a result, precise estimation of both global and local ancestry is required to prevent both false positive and false-negative associations. Here, 820 individuals from South Africa were genotyped on the SNP-dense Illumina Multi-Ethnic Genotyping Array (∼1.7M SNPs) followed by local and global ancestry inference using RFMix. Local ancestry adjusted allelic association (LAAA) models were utilized owing to the extensive genetic heterogeneity present in this population. Hence, an interaction term, comprising the identification of the minor allele that corresponds to the ancestry present at the specific locus under investigation, was included as a covariate. One SNP (rs28647531) located on chromosome 4q22 was significantly associated with TB susceptibility and displayed a SNP minor allelic effect (G allele, frequency = 0.204) whilst correcting for local ancestry for Bantu-speaking African ancestry (p-value = 5.518 × 10−7; OR = 3.065; SE = 0.224). Although no other variants passed the significant threshold, clear differences were observed between the lead variants identified for each ancestry. Furthermore, the LAAA model robustly captured the source of association signals in multi-way admixed individuals from South Africa and allowed the identification of ancestry-specific disease risk alleles associated with TB susceptibility that have previously been missed.

A Cross Sectional Study of Association of HLA typing with Haemoglobin Level in Sickle Cell Anaemia

Background: Sickle-cell Disease (SCD) is the most common blood cell disorder affecting millions of people. In severe cases, regular blood transfusion is an essential practice to relieve clinical symptoms. However, since regular blood transfusion can lead to alloimmunization to foreign human leukocyte antigens (HLA), this may result in severe anemia due to red blood cell destruction. Therefore, this study aimed to determine the association between the hemoglobin level and the presence of HLA genotypes among Sickle Cell Anemia patients. Methodology: A total of 64 SCD patients and 21 healthy donors seen at King Abdulaziz hospital between November 2019 and February 2021 were recruited for this study. Demographic data including ABO/Rhesus blood groups, hemoglobin concentration, were among the clinical information obtained. HLA genotyping was performed using Polymerase Chain Reaction-Sequence Specific Oligonucleotide (PCR-SSO). The data were cleaned using the Microsoft Excel and analysed using the statistical packages for Social Sciences (SPSS) version 24. Results: The incidence of SCD is not strictly gender-related because of its transmission as an autosomal recessive disorder. Sixty-four individuals (33 females; 31 males) having SCD were analyzed. O blood group recorded the highest prevalence compared to other ABO blood groups in SCD patients. After analysing allelic association, HLA-A*02 was more frequent in SCD patients compared to control. After further allelic combination analysis of patients and compared with the control group, HLA-DQB1*02 was majorly involved in overexpression and decreasing hemoglobin level and significantly different among control and experimental groups. Conclusion: Rhesus-positive blood types were more associated with the SCA. HLA- type II alleles could influence the clinical course of sickle cell disease and HLA-DQB1*02 was significantly different among SCD group and control individuals, which signifies the concept that the allele was overexpressed among patients resulting in low Hb level.

Association analysis of variants rs35934224 in TXNRD2 and rs6478746 in LMX1B in primary angle-closure and pseudoexfoliation glaucoma

Objective: Previous genome-wide studies have demonstrated significant pathogenic association between variants rs35934224 within TXNRD2 and rs6478746 near LMX1B in primary open-angle glaucoma. We investigated the association between these variants in primary angle-closure glaucoma (PACG) and pseudoexfoliation glaucoma (PXG) patients of Saudi origin. Methods: In a case-control study, DNA samples from 249 controls (135 men and 114 women), 100 PACG cases (44 men and 56 women), and 95 PXG cases (61 men and 34 women) were genotyped by TaqMan® based real-time PCR. Statistical tests were performed to evaluate genetic association with glaucoma types and related clinical indices. Results: The allele frequencies of rs35934224 and rs6478746 did not show significant variation in PACG and PXG than controls, except that the rs35934224[T] allele was found to be significantly low among PXG women (0.10) as compared to controls (0.21) (odds ratio = 0.38, 95% confidence interval = 0.16–0.94, p = 0.024). Rs35934224 genotypes showed a nominal-to-borderline protective association with PACG and PXG among women in different genetic models. However, except for the over-dominant model in PACG ( p = 0.0095), none of the effects survived Bonferroni’s correction ( p < 0.01). Rs6478746 showed no significant genotype or allelic association with PACG and PXG. Regression analysis showed no influence on disease outcome, and neither showed any correlation with intraocular pressure and cup/disk ratio in both PACG and PXG. Conclusions: Variants rs35934224 in TXNRD2 and rs6478746 near LMX1B are not associated with PACG and PXG in the Saudi cohort, but rs35934224 may confer modest protection among women. Further population-based studies are needed to validate these results.

Exploring chromatin structural roles of non-coding RNAs at imprinted domains

Different classes of non-coding RNA (ncRNA) influence the organization of chromatin. Imprinted gene domains constitute a paradigm for exploring functional long ncRNAs (lncRNAs). Almost all express an lncRNA in a parent-of-origin dependent manner. The mono-allelic expression of these lncRNAs represses close by and distant protein-coding genes, through diverse mechanisms. Some control genes on other chromosomes as well. Interestingly, several imprinted chromosomal domains show a developmentally regulated, chromatin-based mechanism of imprinting with apparent similarities to X-chromosome inactivation. At these domains, the mono-allelic lncRNAs show a relatively stable, focal accumulation in cis. This facilitates the recruitment of Polycomb repressive complexes, lysine methyltranferases and other nuclear proteins — in part through direct RNA–protein interactions. Recent chromosome conformation capture and microscopy studies indicate that the focal aggregation of lncRNA and interacting proteins could play an architectural role as well, and correlates with close positioning of target genes. Higher-order chromatin structure is strongly influenced by CTCF/cohesin complexes, whose allelic association patterns and actions may be influenced by lncRNAs as well. Here, we review the gene-repressive roles of imprinted non-coding RNAs, particularly of lncRNAs, and discuss emerging links with chromatin architecture.

Association between the FTO A/T Polymorphism and Elite Athlete Status in Caucasian Swimmers

The FTO A/T polymorphism (rs9939609) has been strongly associated with body mass-related traits in nonathletic populations, but rarely with elite athletic performance. The aim of the study was to investigate the association between the A/T polymorphism and athlete status in elite swimmers. Polish swimmers (n = 196) who competed in national and international competition at short- (SDS; 50–200 m; n = 147) and long-distance events (LDS; ≥400 m; n = 49) were recruited. The control group included 379 unrelated, sedentary young participants. The participants were all Caucasians. Genotyping was carried out using real-time PCR. It was found that the chance of being an elite swimmer was lower in carriers of the AT and AA genotype compared with TT homozygotes (1.5 and 2.0 times, respectively). These findings were confirmed in an allelic association; the A allele was less frequent in the swimmers compared with controls (p = 0.004). However, when SDS were compared against LDS, no significant differences were observed in genotypic and allelic distribution. The results of our experiment suggest that the variation within the FTO gene can affect elite athlete status. It was demonstrated that harboring the T allele may be beneficial for achieving success in a sport such as swimming.

Landscape Genetic Connectivity and Evidence for Recombination in the North American Population of the White-Nose Syndrome Pathogen, Pseudogymnoascus destructans

White-Nose Syndrome is an ongoing fungal epizootic caused by epidermal infections of the fungus, Pseudogymnoascus destructans (P. destructans), affecting hibernating bat species in North America. Emerging early in 2006 in New York State, infections of P. destructans have spread to 38 US States and seven Canadian Provinces. Since then, clonal isolates of P. destructans have accumulated genotypic and phenotypic variations in North America. Using microsatellite and single nucleotide polymorphism markers, we investigated the population structure and genetic relationships among P. destructans isolates from diverse regions in North America to understand its pattern of spread, and to test hypotheses about factors that contribute to transmission. We found limited support for genetic isolation of P. destructans populations by geographic distance, and instead identified evidence for gene flow among geographic regions. Interestingly, allelic association tests revealed evidence for recombination in the North American P. destructans population. Our landscape genetic analyses revealed that the population structure of P. destructans in North America was significantly influenced by anthropogenic impacts on the landscape. Our results have important implications for understanding the mechanism(s) of P. destructans spread.

Analysis of Single Nucleotide Polymorphisms on Locus 13q33.1-34 in Multigenerational Families of Cleft Lip Palate using MassArray

BACKGROUND: Cleft lip palate is a common congenital anomaly with multifactorial etiology. Many high-risk markers at different loci were reported to be involved in its etiology. Advanced genetic research led to the discovery of evidence of a new linkage on 13q33.1-34 region at marker rs1830756 in two multigenerational Indian families. However, no further study was reported to confirm or validate this linkage in other families. Hence, the present study was designed.METHODS: Twenty multigenerational families affected by non-syndromic cleft lip palate were selected for the study. Polymorphisms, rs1830756, rs1323672, rs1935135 of FAM155A gene; rs1961495, rs953386, rs1411040 of COL4A1 gene; and rs726449, rs984300 of MYO16 gene were selected. Genomic DNA was isolated and sent for genetic analysis by single nucleotide polymorphism (SNP) genotyping using the MassArray method. Statistical analysis of the genomic data was done by PLINK. Bonferroni correction was applied and haplotype analysis was done using Haploview software.RESULTS: Polymorphisms followed the Hardy Weinberg Equilibrium. In the allelic association, all the polymorphisms analysed showed no statistical significance. Hence, there was no significant difference in the allelic frequencies between non-syndromic cleft lip palate patients and healthy controls. The odds ratio was not more than 1.6 for all the SNPs. Haplotype analysis showed that haplotypes were not significantly higher in non-syndromic cleft patients than in control subjects.CONCLUSION: There is no association between SNPs analysed in the locus 13q33.1-34 with cleft lip palate.KEYWORDS: cleft lip palate, chromosome, polymorphism

Association of Single Nucleotide Polymorphisms on Locus 18q21.1 in the Etiology of Nonsyndromic Cleft Lip Palate (NSCLP) in Indian Multiplex Families

Background Cleft lip palate (CLP) is a common congenital anomaly with multifactorial etiology. Many polymorphisms at different loci on multiple chromosomes were reported to be involved in its etiology. Genetic research on a single multigenerational American family reported 18q21.1 locus as a high-risk locus for nonsyndromic CLP (NSCLP). However, its association in multiple multiplex families and Indian population is not analyzed for its association in NSCLP. Aim This study was aimed to evaluate whether high-risk single nucleotide polymorphisms (SNPs) on chromosome 18q21.1 are involved in the etiology of NSCLP in multiplex Indian families. Materials and Methods Twenty multigenerational families affected by NSCLP were selected for the study after following inclusion and exclusion criteria. Genomic DNA was isolated from the affected and unaffected members of these 20 multiplex families and sent for genetic analysis. High-risk polymorphisms, such as rs6507872 and rs8091995 of CTIF, rs17715416, rs17713847 and rs183559995 of MYO5B, rs78950893 of SMAD7, rs1450425 of LOXHD1, and rs6507992 of SKA1 candidate genes on the 18q21.1 locus, were analyzed. SNP genotyping was done using the MassARRAY method. Statistical analysis of the genomic data was done by PLINK. Results Polymorphisms followed the Hardy–Weinberg equilibrium. In the allelic association, all the polymorphisms had a p-value more than 0.05. The odds ratio was not more than 1.6 for all the SNPs. Conclusion High-risk polymorphisms, such as rs6507872 and rs8091995 of CTIF, rs17715416, rs17713847 and rs183559995 of MYO5B, rs78950893 of SMAD7, rs1450425 of LOXHD1, and rs6507992 of SKA1 in the locus 18q21.1, are not associated with NSCLP in Indian multiplex families.