Search results for "Polymorphism"
showing 10 items of 1968 documents
Microduplications At 22q11.21 are Associated with Classic Bladder Exstrophy
2010
Purpose Classic exstrophy of the bladder (CBE) is part of the exstrophy-epispadias complex (EEC), a spectrum of urogenital anomalies in which part or all of the distal urinary tract fails to close. Familial occurrence has been observed, and previous studies have suggested an underlying multifactorial mode of inheritance. To date, no causative genetic or non-genetic factor has been unequivocally identified in humans. The present study aimed to identify microaberrations characterized by loss or gain of genomic material that contribute to the EEC at a genome-wide level. Material and Methods Molecular karyotyping, utilizing 549,839 single nucleotide polymorphisms (SNPs) with an average spacing …
Identification and prevention of genotyping errors caused by G-quadruplex- and i-motif-like sequences.
2009
Abstract Background: Reliable PCR amplification of DNA fragments is the prerequisite for most genetic assays. We investigated the impact of G-quadruplex– or i-motif–like sequences on the reliability of PCR-based genetic analyses. Methods: We found the sequence context of a common intronic polymorphism in the MEN1 gene (multiple endocrine neoplasia I) to be the cause of systematic genotyping errors by inducing preferential amplification of one allelic variant [allele dropout (ADO)]. Bioinformatic analyses and pyrosequencing-based allele quantification enabled the identification of the underlying DNA structures. Results: We showed that G-quadruplex– or i-motif–like sequences can reproducibly …
The haplotype distribution of two genes of citrus tristeza virus is altered after host change or aphid transmission.
1999
Genetic variability of citrus tristeza virus (CTV) was studied using the haplotypes detected by single-strand conformation polymorphism (SSCP) analysis of genes p18 and p20 in six virus populations of two origins. The Spanish group included a CTV isolate and subisolates obtained by graft-transmission to different host species. The other included two subisolates aphid-transmitted from a single Japanese isolate. The homozygosity observed for gene p20 was always significantly higher than that expected under neutral evolution, whereas only three populations showed high homozygosity for p18, suggesting stronger host constraints for p20 than for p18. Sequential transmissions of a Spanish isolate …
Successful Replication of GWAS Hits for Multiple Sclerosis in 10,000 Germans Using the Exome Array
2015
Genome-wide association studies (GWAS) successfully identified various chromosomal regions to be associated with multiple sclerosis (MS). The primary aim of this study was to replicate reported associations from GWAS using an exome array in a large German study. German MS cases (n = 4,476) and German controls (n = 5,714) were genotyped using the Illumina HumanExome v1-Chip. Genotype calling was performed with the Illumina Genome Studio(TM) Genotyping Module, followed by zCall. Single-nucleotide polymorphisms (SNPs) in seven regions outside the human leukocyte antigen (HLA) region showed genome-wide significant associations with MS (P values < 5 × 10(-8) ). These associations have been repor…
Genetic differentiation in the striped dolphin Stenella coeruleoalba from European waters according to mitochondrial DNA (mtDNA) restriction analysis
1999
We used mitochondrial DNA (mtDNA) restriction analysis to study genetic variation in 98 striped dolphins (Stenella coeruleoalba) stranded on coasts from different European countries and from animals caught by fisheries. A total of 63 different restriction sites was mapped after digestion of mtDNA with 15 restriction endonucleases that yielded a total of 27 haplotypes. No haplotype was shared between Mediterranean and Atlantic areas. All the analyses indicate the existence of two different populations with a very limited gene flow across the Strait of Gibraltar.
Temporal changes of chromosomal polymorphism in natural populations of Drosophila subobscura
1984
The behaviour of the chromosomal polymorphism of D. subobscura was analyzed in relation to temporal changes, daily, seasonal and annual. Firstly, chromosome analyses were carried out over a year in a natural population. Samples were taken at monthly intervals in Tibidabo, a locality close to Barcelona. In all the months except January, the number of individuals captured was enough to carry out a chromosome analysis of that population. The A, E and O chromosomes showed a great uniformity in the frequencies of gene arrangement over the year. However, significant changes occur in the frequencies of J and U chromosomes. The J1 and U1+2+8 arrangements showed a similar tendency, with two maxima, …
A study of the polymorphism and ethnic distribution differences of human serum paraoxonase
1983
The enzyme serum paraoxonase shows a polymorphism in Europeans which is governed by two alleles. The first allele has a gene frequency plow of 0.716–0.777, and is manifested as a low activity group in homozygotes. More than 50% of all European test subjects can be included in this group. A second allele with a gene frequency qhigh of 0.223–0.284 was found in typical European distributions and is manifested in both the form of a second heterozygotic and a third homozygotic group with high activities. The Hardy-Weinberg rule for a two-allele model is valid for the distribution. The gene frequency plow of the first allele decreases as one moves from Europe in the direction of Africa and Asia. …
PrP Gene Polymorphism in Medieval Remains of Sicilian Sheep
2015
Encephalopathy in sheep was at first described in Ireland in 1732 and was called scrapie. Ancient DNA in archaeogenetics represents an effective method to evaluate the ancestral pedigree of living animals and track evolutionary changes occurred between the past and the present day. Since several point mutations are today widely described in modern scrapie, no data about both sequence and frequency are still available for the prion protein (PrP) gene in ancient breeds. In order to evaluate whether the haplotypes distribution in ancient sheep differed from those of the modern population we evaluated polymorphism at four well know codons of the Prp Open Reading Frame. In the present work, we c…
Genetic analysis of IDDM: The GAW5 multiplex family dataset
1989
In a collaborative effort by 12 centers from Europe and North America, data were assembled from 94 multiplex families with insulin-dependent diabetes mellitus (IDDM) for analysis of genetic and other factors of possible etiological importance. The dataset contains information on the following genetic markers: HLA-DR beta and -DQ beta restriction fragment length polymorphisms (RFLPs), three RFLPs detected with two probes that map 5' to the insulin gene, the serologically defined HLA loci, and the immunoglobulin allotypes. Data also were included for auto-antibodies to insulin and pancreatic islet cells as possible indicators of pathogenesis and for antibodies to certain viruses that have bee…
Beta-lactoglobulin polymorphism in Girgentana goat breed
2007
Beta-lactoglobulin (b-lg) is a globular protein belonging to the lipocalin family. It is the major whey protein in the milk of ruminants. It is also present in the milk of most mammals but is lacking in rodents, lagomorphs and humans. A large number of variants have been reported for cow and sheep milk. Several studies have shown association between b-lg variants and milk production and composition, even if the results are not always concordant. In goat, no b-lg variants related with amino acid change have been characterized at DNA level, but some authors described the presence of polymorphisms in the 3’UTR and in the proximal promoter region. Mutations in the promoter region could be those…