939 resultados para genome wide complex trait analysis


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Lung cancer is the leading cause of cancer-related mortality in the US. Emerging evidence has shown that host genetic factors can interact with environmental exposures to influence patient susceptibility to the diseases as well as clinical outcomes, such as survival and recurrence. We aimed to identify genetic prognostic markers for non-small cell lung cancer (NSCLC), a major (85%) subtype of lung cancer, and also in other subgroups. With the fast evolution of genotyping technology, genetic association studies have went through candidate gene approach, to pathway-based approach, to the genome wide association study (GWAS). Even in the era of GWAS, pathway-based approach has its own advantages on studying cancer clinical outcomes: it is cost-effective, requiring a smaller sample size than GWAS easier to identify a validation population and explore gene-gene interactions. In the current study, we adopted pathway-based approach focusing on two critical pathways - miRNA and inflammation pathways. MicroRNAs (miRNA) post-transcriptionally regulate around 30% of human genes. Polymorphisms within miRNA processing pathways and binding sites may influence patients’ prognosis through altered gene regulation. Inflammation plays an important role in cancer initiation and progression, and also has shown to impact patients’ clinical outcomes. We first evaluated 240 single nucleotide polymorphisms (SNPs) in miRNA biogenesis genes and predicted binding sites in NSCLC patients to determine associations with clinical outcomes in early-stage (stage I and II) and late-stage (stage III and IV) lung cancer patients, respectively. First, in 535 early-stage patients, after correcting multiple comparisons, FZD4:rs713065 (hazard ratio [HR]:0.46, 95% confidence interval [CI]:0.32-0.65) showed a significant inverse association with survival in early stage surgery-only patients. SP1:rs17695156 (HR:2.22, 95% CI:1.44-3.41) and DROSHA:rs6886834 (HR:6.38, 95% CI:2.49-16.31) conferred increased risk of progression in the all patients and surgery-only populations, respectively. FAS:rs2234978 was significantly associated with improved survival in all patients (HR:0.59, 95% CI:0.44-0.77) and in the surgery plus chemotherapy populations (HR:0.19, 95% CI:0.07-0.46).. Functional genomics analysis demonstrated that this variant creates a miR-651 binding site resulting in altered miRNA regulation of FAS, providing biological plausibility for the observed association. We then analyzed these associations in 598 late-stage patients. After multiple comparison corrections, no SNPs remained significant in the late stage group, while the top SNP NAT1:rs15561 (HR=1.98, 96%CI=1.32-2.94) conferred a significantly increased risk of death in the chemotherapy subgroup. To test the hypothesis that genetic variants in the inflammation-related pathways may be associated with survival in NSCLC patients, we first conducted a three-stage study. In the discovery phase, we investigated a comprehensive panel of 11,930 inflammation-related SNPs in three independent lung cancer populations. A missense SNP (rs2071554) in HLA-DOB was significantly associated with poor survival in the discovery population (HR: 1.46, 95% CI: 1.02-2.09), internal validation population (HR: 1.51, 95% CI: 1.02-2.25), and external validation (HR: 1.52, 95% CI: 1.01-2.29) population. Rs2900420 in KLRK1 was significantly associated with a reduced risk for death in the discovery (HR: 0.76, 95% CI: 0.60-0.96) and internal validation (HR: 0.77, 95% CI: 0.61-0.99) populations, and the association reached borderline significance in the external validation population (HR: 0.80, 95% CI: 0.63-1.02). We also evaluated these inflammation-related SNPs in NSCLC patients in never smokers. Lung cancer in never smokers has been increasingly recognized as distinct disease from that in ever-smokers. A two-stage study was performed using a discovery population from MD Anderson (411 patients) and a validation population from Mayo Clinic (311 patients). Three SNPs (IL17RA:rs879576, BMP8A:rs698141, and STK:rs290229) that were significantly associated with survival were validated (pCD74:rs1056400 and CD38:rs10805347) were borderline significant (p=0.08) in the Mayo Clinic population. In the combined analysis, IL17RA:rs879576 resulted in a 40% reduction in the risk for death (p=4.1 × 10-5 [p=0.61, heterogeneity test]). We also validated a survival tree created in MD Anderson population in the Mayo Clinic population. In conclusion, our results provided strong evidence that genetic variations in specific pathways that examined (miRNA and inflammation pathways) influenced clinical outcomes in NSCLC patients, and with further functional studies, the novel loci have potential to be translated into clinical use.

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Nonsyndromic cleft lip with or without cleft palate (NSCLP) is a common birth defect with a multifactorial etiology. Despite decades of research, the genetic underpinnings of NSCLP still remain largely unexplained. A genome wide association study (GWAS) of a large NSCLP African American family with seven affected individuals across three generations found evidence for linkage at 8q21.3-24.12 (LOD = 2.98). This region contained three biologically relevant candidate genes: Frizzled-6 (FZD6) (LOD = 2.8), Matrilin-2 (MATN2) (LOD = 2.3), and Solute Carrier Family 25, Member 32 (SLC26A32) (LOD = 1.6). Sequencing of the coding regions and the 5’ and 3’ UTRs of these genes in two affected family members identified a rare intronic variant, rs138557689 (c.-153+432A>C), in FZD6. The rs138557689/C allele segregated with the NSCLP phenotype; in silico analysis predicted and EMSA analysis showed that the 138557689/C allele creates new DNA binding sites. FZD6 is part of the WNT pathway, which is involved in craniofacial development, including midface development and upper lip fusion. Our novel findings suggest that an alteration in FZD6 gene regulation may perturb this tightly controlled biological pathway and in turn contribute to the development of NSCLP in this family. Studies are underway to further define how the rs138557689/C variant affects expression of FZD6.

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Introduction. Distant metastasis remains the leading cause of death among prostate cancer patients. Several genetic susceptibility loci associated with Prostate cancer have been identified by the Genome Wide Association Studies (GWAS). To date, few studies have explored the ability of these SNPs to identify metastatic prostate cancer. Based on the identification of genetic variants as predictors of aggressive disease, a case comparison study of prostate cancer patients was designed to explore the association of 96 GWAS single nucleotide polymorphisms (SNPs) with metastatic disease. ^ Method. 1242 histologically confirmed prostate cancer patients, with and without metastatic disease, were enrolled into the study. Data were collected from personal interviews, hospital database and abstraction of medical records. Ninety six SNPs identified from GWAS studies based on their associations with prostate cancer risk were genotyped in the study population. Univariate and multivariate logistic regression analyses were used to explore the relationships of the variants with metastatic prostate cancer in Whites and African American men. ^ Results. Four SNPs showed independent associations with metastatic prostate cancer (rs721048 in EHBP1 (2p15), rs3025039 in VEGF (6p12), rs11228565 in Intergenic(11q13.2) and rs2735839 in KLK3(19q13.33)) in the White population. For SNP rs2735839 in KLK3, genotype GA was 1.71 times as likely to be associated with metastatic prostate cancer diagnosis as genotype AA after adjusting for other significant SNPs and covariates (95% CI, 1.12-2.60; p=0.012). In men of African descent, three SNPs: rs1512268 in NKX3-1(8p21.2), rs12155172 in intergenic (7p15.3) & rs10486567 in JAZF1 (7p15.2) were positively associated with metastatic disease in the multivariate analysis. The strongest SNP was rs1512268 heterozygous genotype AG in NKX3-1(8p21.2) which was associated with 3.97-fold increased risk of metastatic prostate cancer diagnosis (95% CI, 1.69-9.34; p =0.002). ^ Conclusion. Genetic variants associated with metastatic prostate cancer were different in Whites and African American men. Given the high mortality rate recorded in men diagnosed with metastatic prostate tumor, further studies are needed to validate associations and establish their clinical application.^

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Pancreatic cancer is the 4th most common cause for cancer death in the United States, accompanied by less than 5% five-year survival rate based on current treatments, particularly because it is usually detected at a late stage. Identifying a high-risk population to launch an effective preventive strategy and intervention to control this highly lethal disease is desperately needed. The genetic etiology of pancreatic cancer has not been well profiled. We hypothesized that unidentified genetic variants by previous genome-wide association study (GWAS) for pancreatic cancer, due to stringent statistical threshold or missing interaction analysis, may be unveiled using alternative approaches. To achieve this aim, we explored genetic susceptibility to pancreatic cancer in terms of marginal associations of pathway and genes, as well as their interactions with risk factors. We conducted pathway- and gene-based analysis using GWAS data from 3141 pancreatic cancer patients and 3367 controls with European ancestry. Using the gene set ridge regression in association studies (GRASS) method, we analyzed 197 pathways from the Kyoto Encyclopedia of Genes and Genomes (KEGG) database. Using the logistic kernel machine (LKM) test, we analyzed 17906 genes defined by University of California Santa Cruz (UCSC) database. Using the likelihood ratio test (LRT) in a logistic regression model, we analyzed 177 pathways and 17906 genes for interactions with risk factors in 2028 pancreatic cancer patients and 2109 controls with European ancestry. After adjusting for multiple comparisons, six pathways were marginally associated with risk of pancreatic cancer ( P < 0.00025): Fc epsilon RI signaling, maturity onset diabetes of the young, neuroactive ligand-receptor interaction, long-term depression (Ps < 0.0002), and the olfactory transduction and vascular smooth muscle contraction pathways (P = 0.0002; Nine genes were marginally associated with pancreatic cancer risk (P < 2.62 × 10−5), including five reported genes (ABO, HNF1A, CLPTM1L, SHH and MYC), as well as four novel genes (OR13C4, OR 13C3, KCNA6 and HNF4 G); three pathways significantly interacted with risk factors on modifying the risk of pancreatic cancer (P < 2.82 × 10−4): chemokine signaling pathway with obesity ( P < 1.43 × 10−4), calcium signaling pathway (P < 2.27 × 10−4) and MAPK signaling pathway with diabetes (P < 2.77 × 10−4). However, none of the 17906 genes tested for interactions survived the multiple comparisons corrections. In summary, our current GWAS study unveiled unidentified genetic susceptibility to pancreatic cancer using alternative methods. These novel findings provide new perspectives on genetic susceptibility to and molecular mechanisms of pancreatic cancer, once confirmed, will shed promising light on the prevention and treatment of this disease. ^

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The success of an aquaculture breeding program critically depends on the way in which the base population of breeders is constructed since all the genetic variability for the traits included originally in the breeding goal as well as those to be included in the future is contained in the initial founders. Traditionally, base populations were created from a number of wild strains by sampling equal numbers from each strain. However, for some aquaculture species improved strains are already available and, therefore, mean phenotypic values for economically important traits can be used as a criterion to optimize the sampling when creating base populations. Also, the increasing availability of genome-wide genotype information in aquaculture species could help to refine the estimation of relationships within and between candidate strains and, thus, to optimize the percentage of individuals to be sampled from each strain. This study explores the advantages of using phenotypic and genome-wide information when constructing base populations for aquaculture breeding programs in terms of initial and subsequent trait performance and genetic diversity level. Results show that a compromise solution between diversity and performance can be found when creating base populations. Up to 6% higher levels of phenotypic performance can be achieved at the same level of global diversity in the base population by optimizing the selection of breeders instead of sampling equal numbers from each strain. The higher performance observed in the base population persisted during 10 generations of phenotypic selection applied in the subsequent breeding program.

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There is an increasing interest in understanding the role of epigenetic variability in forest species and how it may contribute to their rapid adaptation to changing environments. In this study we have conducted a genome-wide analysis of cytosine methylation pattern in Pinus pinea, a species characterized by very low levels of genetic variation and a remarkable degree of phenotypic plasticity. DNA methylation profiles of different vegetatively propagated trees from representative natural Spanish populations of P. pinea were analyzed with the Methylation Sensitive Amplified Polymorphism (MSAP) technique. A high degree of cytosine methylation was detected (64.36% of all scored DNA fragments). Furthermore, high levels of epigenetic variation were observed among the studied individuals. This high epigenetic variation found in P. pinea contrasted with the lack of genetic variation based on Amplified Fragment Length Polymorphism (AFLP) data. In this manner, variable epigenetic markers clearly discriminate individuals and differentiates two well represented populations while the lack of genetic variation revealed with the AFLP markers fail to differentiate at both, individual or population levels. In addition, the use of different replicated trees allowed identifying common polymorphic methylation sensitive MSAP markers among replicates of a given propagated tree. This set of MSAPs allowed discrimination of the 70% of the analyzed trees.

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Legumes establish a root-nodule symbiosis with soil bacteria collectively known as rhizobia. This symbiosis allows legumes to benefit from the nitrogen fixation capabilities of rhizobia and thus to grow in the absence of any fixed nitrogen source. This is especially relevant for Agriculture, where intensive plant growth depletes soils of useable, fixed nitrogen sources. One of the main features of the root nodule symbiosis is its specificity. Different rhizobia are able to nodulate different legumes. Rhizobium leguminosarum bv. viciae is able to establish an effective symbiosis with four different plant genera (Pisum, Lens, Vicia, Lathyrus), and any given isolate will nodulate any of the four plant genera. A population genomics study with rhizobia isolated from P. sativum, L. culinaris, V. sativa or V. faba, all originating in the same soil, showed that plants select specific genotypes from those available in that soil. This was demonstrated at the genome-wide level, but also for specific genes. Accelerated mesocosm studies with successive plant cultures provided additional evidence on this plant selection and on the nature of the genotypes selected. Finally, representatives from the major rhizobial genotypes isolated from these plants allowed characterization of the size and nature of the respective pangenome and specific genome compartments. These were compared to the different genotypes ?symbiotic and non-symbiotic?present in rhizobial populations isolated directly from the soil without plant intervention.

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The idiopathic inflammatory bowel diseases, Crohn’s disease (CD) and ulcerative colitis (UC), are chronic, frequently disabling diseases of the intestines. Segregation analyses, twin concordance, and ethnic differences in familial risks have established that CD and UC are complex, non-Mendelian, related genetic disorders. We performed a genome-wide screen using 377 autosomal markers, on 297 CD, UC, or mixed relative pairs from 174 families, 37% Ashkenazim. We observed evidence for linkage at 3q for all families (multipoint logarithm of the odds score (MLod) = 2.29, P = 5.7 × 10−4), with greatest significance for non-Ashkenazim Caucasians (MLod = 3.39, P = 3.92 × 10−5), and at chromosome 1p (MLod = 2.65, P = 2.4 × 10−4) for all families. In a limited subset of mixed families (containing one member with CD and another with UC), evidence for linkage was observed on chromosome 4q (MLod = 2.76, P = 1.9 × 10−4), especially among Ashkenazim. There was confirmatory evidence for a CD locus, overlapping IBD1, in the pericentromeric region of chromosome 16 (MLod = 1.69, P = 2.6 × 10−3), particularly among Ashkenazim (MLod = 1.51, P = 7.8 × 10−3); however, positive MLod scores were observed over a very broad region of chromosome 16. Furthermore, evidence for epistasis between IBD1 and chromosome 1p was observed. Thirteen additional loci demonstrated nominal (MLod > 1.0, P < 0.016) evidence for linkage. This screen provides strong evidence that there are several major susceptibility loci contributing to the genetic risk for CD and UC.

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One intradermal injection of incomplete Freund’s adjuvant-oil induces a T cell-mediated inflammatory joint disease in DA rats. Susceptibility genes for oil-induced arthritis (OIA) are located both within and outside the major histocompatibility complex (MHC, Oia1). We have searched for disease-linked non-MHC loci in an F2 intercross between DA rats and MHC-identical but arthritis-resistant LEW.1AV1 rats. A genome-wide scan with microsatellite markers revealed two major chromosome regions that control disease incidence and severity: Oia2 on chromosome 4 (P = 4 × 10−13) and Oia3 on chromosome 10 (P = 1 × 10−6). All animals homozygous for DA alleles at both loci developed severe arthritis, whereas all those homozygous for LEW.1AV1 alleles were resistant. These results have general implications for situations where nonspecific activation of the immune system (e.g., incomplete Freund’s adjuvant-oil) causes inflammation and disease, either alone or in conjunction with specific antigens. They may also provide clues to the etiology of inflammatory diseases in humans, including rheumatoid arthritis.

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The major murine systemic lupus erythematosus (SLE) susceptibility locus Sle1 is syntenic to a chromosomal region linked with SLE susceptibility in multiple human studies. Congenic analyses have shown that Sle1 breaks tolerance to chromatin, a necessary step for full disease induction that can be suppressed by specific modifier loci. In the present study, our fine mapping analysis of the location of Sle1 has determined that three loci within this congenic interval, termed Sle1a, Sle1b, and Sle1c, can independently cause a loss of tolerance to chromatin. Each displays a distinctive profile of serological and cellular characteristics, with T and B cell functions being more affected by Sle1a and Sle1b, respectively. The epistatic interactions of Sle1 with other susceptibility loci to cause severe nephritis cannot be accounted, however, by these three loci alone, suggesting the existence of an additional locus, termed Sle1d. These findings indicate that the potent autoimmune phenotype caused by the Sle1 genomic interval reflects the combined impact of four, separate, susceptibility genes. This level of genetic complexity, combined with similar findings in other systems, supports the possibility that many complex trait loci reflect the impact of polymorphisms in linked clusters of genes with related functions.

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Here we present the successful application of the microarray technology platform to the analysis of DNA polymorphisms. Using the rice genome as a model, we demonstrate the potential of a high-throughput genome analysis method called Diversity Array Technology, DArT‘. In the format presented here the technology is assaying for the presence (or amount) of a specific DNA fragment in a representation derived from the total genomic DNA of an organism or a population of organisms. Two different approaches are presented: the first involves contrasting two representations on a single array while the second involves contrasting a representation with a reference DNA fragment common to all elements of the array. The Diversity Panels created using this method allow genetic fingerprinting of any organism or group of organisms belonging to the gene pool from which the panel was developed. Diversity Arrays enable rapid and economical application of a highly parallel, solid-state genotyping technology to any genome or complex genomic mixtures.

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The SWISS-PROT group at EBI has developed the Proteome Analysis Database utilising existing resources and providing comparative analysis of the predicted protein coding sequences of the complete genomes of bacteria, archaea and eukaryotes (http://www.ebi.ac.uk/proteome/). The two main projects used, InterPro and CluSTr, give a new perspective on families, domains and sites and cover 31–67% (InterPro statistics) of the proteins from each of the complete genomes. CluSTr covers the three complete eukaryotic genomes and the incomplete human genome data. The Proteome Analysis Database is accompanied by a program that has been designed to carry out InterPro proteome comparisons for any one proteome against any other one or more of the proteomes in the database.

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We performed a genome-wide analysis of gene expression in primary human CD15+ myeloid progenitor cells. By using the serial analysis of gene expression (SAGE) technique, we obtained quantitative information for the expression of 37,519 unique SAGE-tag sequences. Of these unique tags, (i) 25% were detected at high and intermediate levels, whereas 75% were present as single copies, (ii) 53% of the tags matched known expressed sequences, 34% of which were matched to more than one known expressed sequence, and (iii) 47% of the tags had no matches and represent potentially novel genes. The correct genes were confirmed by application of the generation of longer cDNA fragments from SAGE tags for gene identification (GLGI) technique for high-copy tags with multiple matches. A set of genes known to be important in myeloid differentiation were expressed at various levels and used different spliced forms. This study provides a normal baseline for comparison of gene expression in myeloid diseases. The strategy of using SAGE and GLGI techniques in this study has broad applications to the genome-wide identification of expressed genes.

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A maioria dos casos de puberdade precoce central (PPC) em meninas permanece idiopática. A hipótese de uma causa genética vem se fortalecendo após a descoberta de alguns genes associados a este fenótipo, sobretudo aqueles implicados com o sistema kisspeptina (KISS1 e KISS1R). Entretanto, apenas casos isolados de PPC foram relacionados à mutação na kisspeptina ou em seu receptor. Até recentemente, a maioria dos estudos genéticos em PPC buscava genes candidatos selecionados com base em modelos animais, análise genética de pacientes com hipogonadismo hipogonadotrófico, ou ainda, nos estudos de associação ampla do genoma. Neste trabalho, foi utilizado o sequenciamento exômico global, uma metodologia mais moderna de sequenciamento, para identificar variantes associadas ao fenótipo de PPC. Trinta e seis indivíduos com a forma de PPC familial (19 famílias) e 213 casos aparentemente esporádicos foram inicialmente selecionados. A forma familial foi definida pela presença de mais de um membro afetado na família. DNA genômico foi extraído dos leucócitos do sangue periférico de todos os pacientes. O estudo de sequenciamento exômico global realizado pela técnica ILLUMINA, em 40 membros de 15 famílias com PPC, identificou mutações inativadoras em um único gene, MKRN3, em cinco dessas famílias. Pesquisa de mutação no MKRN3 realizada por sequenciamento direto em duas famílias adicionais (quatro pacientes) identificou duas novas variantes nesse gene. O MKRN3 é um gene de um único éxon, localizado no cromossomo 15 em uma região crítica para a síndrome de Prader Willi. O gene MKRN3 sofre imprinting materno, sendo expresso apenas pelo alelo paterno. A descoberta de mutações em pacientes com PPC familial despertou o interesse para a pesquisa de mutações nesse gene em 213 pacientes com PPC aparentemente esporádica por meio de reação em cadeia de polimerase seguida de purificação enzimática e sequenciamento automático direto (Sanger). Três novas mutações e duas já anteriormente identificadas, incluindo quatro frameshifts e uma variante missense, foram encontradas, em heterozigose, em seis meninas não relacionadas. Todas as novas variantes identificadas estavam ausentes nos bancos de dados (1000 Genomes e Exome Variant Server). O estudo de segregação familial em três dessas meninas com PPC aparentemente esporádica e mutação no MKRN3 confirmou o padrão de herança autossômica dominante com penetrância completa e transmissão exclusiva pelo alelo paterno, demonstrando que esses casos eram, na verdade, também familiares. A maioria das mutações encontradas no MKRN3 era do tipo frameshift ou nonsense, levando a stop códons prematuros e proteínas truncadas e, portanto, confirmando a associação com o fenótipo. As duas mutações missenses (p.Arg365Ser e p.Phe417Ile) identificadas estavam localizadas em regiões de dedo ou anel de zinco, importantes para a função da proteína. Além disso, os estudos in silico dessas duas variantes demonstraram patogenicidade. Todos os pacientes com mutação no MKRN3 apresentavam características clínicas e hormonais típicas de ativação prematura do eixo reprodutivo. A mediana de idade de início da puberdade foi de 6 anos nas meninas (variando de 3 a 6,5) e 8 anos nos meninos (variando de 5,9 a 8,5). Tendo em vista o fenômeno de imprinting, análise de metilação foi também realizada em um subgrupo de 52 pacientes com PPC pela técnica de MS-MLPA, mas não foram encontradas alterações no padrão de metilação. Em conclusão, este trabalho identificou um novo gene associado ao fenótipo de PPC. Atualmente, mutações inativadoras no MKRN3 representam a causa genética mais comum de PPC familial (33%). O MKRN3 é o primeiro gene imprintado associado a distúrbios puberais em humanos. O mecanismo preciso de ação desse gene na regulação da secreção de GnRH necessita de estudos adicionais

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The South African Boer goat displays a characteristic white spotting phenotype, in which the pigment is limited to the head. Exploiting the existing phenotype variation within the breed, we mapped the locus causing this white spotting phenotype to chromosome 17 by genome wide association. Subsequent whole genome sequencing identified a 1 Mb copy number variant (CNV) harboring 5 genes including EDNRA. The analysis of 358 Boer goats revealed 3 alleles with one, two, and three copies of this CNV. The copy number is correlated with the degree of white spotting in goats. We propose a hypothesis that ectopic overexpression of a mutant EDNRA scavenges EDN3 required for EDNRB signaling and normal melanocyte development and thus likely lead to an absence of melanocytes in the non-pigmented body areas of Boer goats. Our findings demonstrate the value of domestic animals as reservoir of unique mutants and for identifying a precisely defined functional CNV.