Avian major histocompatibility complex copy number variation is associated with helminth richness.
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ABSTRACT:
SUBMITTER: Minias P
PROVIDER: S-EPMC7423054 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:MHC genes, which code for proteins responsible for presenting pathogen-derived antigens to the host immune system, show remarkable copy-number variation both between and within species. However, the evolutionary forces driving this variation are poorly understood. Here, we use computer simulations to investigate whether evolution of the number of MHC variants in the genome can be shaped by the number of pathogen species the host population encounters (pathogen richness). Our model assumed that while increasing a range of pathogens recognised, expressing additional MHC variants also incurs costs such as an increased risk of autoimmunity. We found that pathogen richness selected for high MHC copy number only when the costs were low. Furthermore, the shape of the association was modified by the rate of pathogen evolution, with faster pathogen mutation rates selecting for increased host MHC copy number, but only when pathogen richness was low to moderate. Thus, taking into account factors other than pathogen richness may help explain wide variation between vertebrate species in the number of MHC genes. Within population, variation in the number of unique MHC variants carried by individuals (INV) was observed under most parameter combinations, except at low pathogen richness. This variance gave rise to positive correlations between INV and host immunocompetence (proportion of pathogens recognised). However, within-population variation in host immunocompetence declined with pathogen richness. Thus, counterintuitively, pathogens can contribute more to genetic variance for host fitness in species exposed to fewer pathogen species, with consequences to predictions from "Hamilton-Zuk" theory of sexual selection.
| S-EPMC6541284 | biostudies-literature
Project description:The major histocompatibility complex (MHC) is a fundamental part of the vertebrate immune system, and the high variability in many MHC genes is thought to play an essential role in recognition of parasites. The Przewalski's horse is extinct in the wild and all the living individuals descend from 13 founders, most of whom were captured around the turn of the century. One of the primary genetic concerns in endangered species is whether they have ample adaptive variation to respond to novel selective factors. In examining 14 Przewalski's horses that are broadly representative of the living animals, we found six different class II DRB major histocompatibility sequences. The sequences showed extensive nonsynonymous variation, concentrated in the putative antigen-binding sites, and little synonymous variation. Individuals had from two to four sequences as determined by single-stranded conformation polymorphism (SSCP) analysis. On the basis of the SSCP data, phylogenetic analysis of the nucleotide sequences, and segregation in a family group, we conclude that four of these sequences are from one gene (although one sequence codes for a nonfunctional allele because it contains a stop codon) and two other sequences are from another gene. The position of the stop codon is at the same amino-acid position as in a closely related sequence from the domestic horse. Because other organisms have extensive variation at homologous loci, the Przewalski's horse may have quite low variation in this important adaptive region.
| S-EPMC1460696 | biostudies-other
Project description:While antidepressant treatment response appears to be partially heritable, no consistent genetic associations have been identified. Large, rare copy number variants (CNVs) play a role in other neuropsychiatric diseases, so we assessed their association with treatment-resistant depression (TRD).We analyzed data from two genome-wide association studies comprising 1263 Caucasian patients with major depressive disorder. One was drawn from a large health system by applying natural language processing to electronic health records (i2b2 cohort). The second consisted of a multicenter study of sequential antidepressant treatments, Sequenced Treatment Alternatives to Relieve Depression. The Birdsuite package was used to identify rare deletions and duplications. Individuals without symptomatic remission, despite two antidepressant treatment trials, were contrasted with those who remitted with a first treatment trial.CNV data were derived for 778 subjects in the i2b2 cohort, including 300 subjects (37%) with TRD, and 485 subjects in Sequenced Treatment Alternatives to Relieve Depression cohort, including 152 (31%) with TRD. CNV burden analyses identified modest enrichment of duplications in cases (empirical p = .04 for duplications of 100-200 kilobase) and a particular deletion region spanning gene PABPC4L (empirical p = .02, 6 cases: 0 controls). Pathway analysis suggested enrichment of CNVs intersecting genes regulating actin cytoskeleton. However, none of these associations survived genome-wide correction.Contribution of rare CNVs to TRD appears to be modest, individually or in aggregate. The electronic health record-based methodology demonstrated here should facilitate collection of larger TRD cohorts necessary to further characterize these effects.
| S-EPMC4104153 | biostudies-literature
Project description:Common copy number variations (CNVs) represent a significant source of genetic diversity, yet their influence on phenotypic variability, including disease susceptibility, remains poorly understood. To address this problem in human cancer, we performed a genome-wide association study of CNVs in the childhood cancer neuroblastoma, a disease in which single nucleotide polymorphism variations are known to influence susceptibility. We first genotyped 846 Caucasian neuroblastoma patients and 803 healthy Caucasian controls at approximately 550,000 single nucleotide polymorphisms, and performed a CNV-based test for association. We then replicated significant observations in two independent sample sets comprised of a total of 595 cases and 3,357 controls. Here we describe the identification of a common CNV at chromosome 1q21.1 associated with neuroblastoma in the discovery set, which was confirmed in both replication sets. This CNV was validated by quantitative polymerase chain reaction, fluorescent in situ hybridization and analysis of matched tumour specimens, and was shown to be heritable in an independent set of 713 cancer-free parent-offspring trios. We identified a previously unknown transcript within the CNV that showed high sequence similarity to several neuroblastoma breakpoint family (NBPF) genes and represents a new member of this gene family (NBPF23). This transcript was preferentially expressed in fetal brain and fetal sympathetic nervous tissues, and the expression level was strictly correlated with CNV state in neuroblastoma cells. These data demonstrate that inherited copy number variation at 1q21.1 is associated with neuroblastoma and implicate a previously unknown neuroblastoma breakpoint family gene in early tumorigenesis of this childhood cancer.
| S-EPMC2755253 | biostudies-literature
Project description:Genetic markers for distant metastatic disease in patients with colorectal cancer (CRC) are not well defined. Identification of genetic alterations associated with metastatic CRC could help to guide systemic and local treatment strategies. We evaluated the association of tumor necrosis factor receptor superfamily member 10C (TNFRSF10C) copy number variation (CNV) with distant metastatic disease in patients with CRC using The Cancer Genome Atlas (TCGA).Genetic sequencing data and clinical characteristics were obtained from TCGA for all available patients with CRC. There were 515 CRC patient samples with CNV and clinical outcome data, including a subset of 144 rectal adenocarcinoma patient samples. Using the TCGA CRC dataset, CNV of TNFRSF10C was evaluated for association with distant metastatic disease (M1 vs. M0). Multivariate logistic regression analysis with odds ratio (OR) using a 95% confidence interval (CI) was performed adjusting for age, T stage, N stage, adjuvant chemotherapy, gender, microsatellite instability (MSI), location, and surgical margin status.TNFRSF10C CNV in patients with CRC was associated with distant metastatic disease [OR 4.81 (95% CI, 2.13-10.85) P<0.001] and positive lymph nodes [OR 18.83 (95% CI, 8.42-42.09)]; P<0.001) but not MSI (OR P=0.799). On multivariate analysis, after adjusting for pathologic T stage, N stage, adjuvant chemotherapy, gender, and MSI, TNFRSF10C CNV remained significantly associated with distant metastatic disease (OR P=0.018). Subset analysis revealed that TNFRSF10C CNV was also significantly associated with distant metastatic disease in patients with rectal adenocarcinoma (OR P=0.016).TNFRSF10C CNV in patients with CRC is associated with distant metastatic disease. With further validation, such genetic profiles could be used clinically to support optimal systemic treatment strategies versus more aggressive local therapies in patients with CRC, including radiation therapy for rectal adenocarcinoma.
| S-EPMC4880759 | biostudies-other
Project description:The human genome contains hundreds of thousands of regions harboring copy-number variants (CNV). However, the phenotypic effects of most such polymorphisms are unknown because only larger CNVs have been ascertainable from SNP-array data generated by large biobanks. We developed a computational approach leveraging haplotype sharing in biobank cohorts to more sensitively detect CNVs. Applied to UK Biobank, this approach accounted for approximately half of all rare gene inactivation events produced by genomic structural variation. This CNV call set enabled a detailed analysis of associations between CNVs and 56 quantitative traits, identifying 269 independent associations (p < 5 × 10-8) likely to be causally driven by CNVs. Putative target genes were identifiable for nearly half of the loci, enabling insights into dosage sensitivity of these genes and uncovering several gene-trait relationships. These results demonstrate the ability of haplotype-informed analysis to provide insights into the genetic basis of human complex traits.
| S-EPMC9800003 | biostudies-literature
Project description:amphibian MHC IIB1 Raw sequence reads
| PRJNA862637 | ENA
Project description:Chromosomal rearrangements and copy number variants (CNVs) play key roles in genome evolution and genetic disease; however, the molecular mechanisms underlying these types of structural genomic variation are not fully understood. The availability of complete genome sequences for two bird species, the chicken and the zebra finch, provides, for the first time, an ideal opportunity to analyze the relationship between structural genomic variation (chromosomal and CNV) and recombination on a genome-wide level. The aims of this study were therefore threefold: (1) to combine bioinformatics, physical mapping to produce comprehensive comparative maps of the genomes of chicken and zebra finch. In so doing, this allowed the identification of evolutionary chromosomal rearrangements distinguishing them. The previously reported interchromosomal conservation of synteny was confirmed, but a larger than expected number of intrachromosomal rearrangements were reported; (2) to hybridize zebra finch genomic DNA to a chicken tiling path microarray and identify CNVs in the zebra finch genome relative to chicken; 32 interspecific CNVs were identified; and (3) to test the hypothesis that there is an association between CNV, chromosomal rearrangements, and recombination by correlating data from (1) and (2) with recombination rate data from a high-resolution genetic linkage map of the zebra finch. We found a highly significant association of both chromosomal rearrangements and CNVs with elevated recombination rates. The results thus provide support for the notion of recombination-based processes playing a major role in avian genome evolution.
| S-EPMC2847753 | biostudies-literature
Project description:BackgroundCopy number variation (CNV) is a major source of structural variants and has been commonly identified in mammalian genome. It is associated with gene expression and may present a major genetic component of phenotypic diversity. Unlike many other mammalian genomes where CNVs have been well annotated, studies of porcine CNV in diverse breeds are still limited.ResultHere we used Porcine SNP60 BeadChip and PennCNV algorithm to identify 1,315 putative CNVs belonging to 565 CNV regions (CNVRs) in 1,693 pigs from 18 diverse populations. Total 538 out of 683 CNVs identified in a White Duroc?×?Erhualian F2 population fit Mendelian transmission and 6 out of 7 randomly selected CNVRs were confirmed by quantitative real time PCR. CNVRs were non-randomly distributed in the pig genome. Several CNV hotspots were found on pig chromosomes 6, 11, 13, 14 and 17. CNV numbers differ greatly among different pig populations. The Duroc pigs were identified to have the most number of CNVs per individual. Among 1,765 transcripts located within the CNVRs, 634 genes have been reported to be copy number variable genes in the human genome. By integrating analysis of QTL mapping, CNVRs and the description of phenotypes in knockout mice, we identified 7 copy number variable genes as candidate genes for phenotypes related to carcass length, backfat thickness, abdominal fat weight, length of scapular, intermuscle fat content of logissimus muscle, body weight at 240 day, glycolytic potential of logissimus muscle, mean corpuscular hemoglobin, mean corpuscular volume and humerus diameter.ConclusionWe revealed the distribution of the unprecedented number of 565 CNVRs in pig genome and investigated copy number variable genes as the possible candidate genes for phenotypic traits. These findings give novel insights into porcine CNVs and provide resources to facilitate the identification of trait-related CNVs.
| S-EPMC3543711 | biostudies-literature
Project description:BackgroundC-C motif Chemokine Ligand 3 Like 1 (CCL3L1) is a multiallelic copy number variable, which plays a crucial role in immunoregulatory and hosts defense through the production of macrophage inflammatory protein (MIP)-1α. Variable range of the CCL3L1 copies from 0 to 14 copies have been documented in several different populations. However, there is still lack of report on the range of CCL3L1 copy number exclusively among Malaysians who are a multi-ethnic population. Thus, this study aims to extensively examine the distribution of CCL3L1 copy number in the three major populations from Malaysia namely Malay, Chinese and Indian. A diploid copy number of CCL3L1 for 393 Malaysians (Malay = 178, Indian = 90, and Chinese = 125) was quantified using Paralogue Ratio Tests (PRTs) and then validated with microsatellites analysis.ResultsTo our knowledge, this is the first report on the CCL3L1 copy number that has been attempted among Malaysians and the Chinese ethnic group exhibits a diverse pattern of CCL3L1 distribution copy number from the Malay and Indian (p < 0.0001). The CCL3L1 ranged from 0 to 8 copies for both the Malay and Indian ethnic groups while 0 to 10 copies for the Chinese ethnic. Consequently, the CCL3L1 copy number among major ethnic groups in the Malaysian population is found to be significantly varied when compared to the European population (p < 0.0001). The mean/median reported for the Malay, Chinese, Indian, and European are 2.759/2.869, 3.453/3.290, 2.437/1.970 and 2.001/1.940 respectively.ConclusionThis study reveals the existence of genetic variation of CCL3L1 in the Malaysian population, and suggests by examining genetic diversity on the ethnicity, and specific geographical region could help in reconstructing human evolutionary history and for the prediction of disease risk related to the CCL3L1 copy number.
| S-EPMC6942282 | biostudies-literature