Search results for "LOCUS"
showing 10 items of 632 documents
Two distinct amplification events of the c-myc locus in a colorectal tumour.
2008
Southern hybridisation of genomic DNA extracted from a human primary colorectal carcinoma revealed amplification of a fragment containing the wild-type c-myc locus. Two additional rearranged DNA fragments, lying upstream of c-myc, fused to distant non-contiguous sequences from the same chromosome, with an opposite configuration (head to head vs. head to tail), were also found to be amplified. Sequences analysis suggested that these rearrangements resulted from illegitimate recombination at two distinct points within the DNA sequence just upstream of the c-myc ORF and further that these events triggered two different amplification mechanisms, only one of which, involving a strand invasion ev…
Accelerated Evolution of Fetuin-A (FETUA, also AHSG) is Driven by Positive Darwinian Selection, not GC-Biased Gene Conversion
2009
article i nfo Human Fetuin-A (FETUA, also termed AHSG) is a serum protein composed of two cystatin-like domains D1 and D2 of together 235 amino acids (aa) and an unrelated domain D3 of 114 aa. Though the protein plays a role in diverse physiological and pathological processes, comparably little is known about sequence evolution of FETUA. We therefore analyzed its molecular evolution on the basis of coding sequences of 16 primate species. Ratios of non-synonymous to synonymous substitution rates (dn/ds= ω) suggest that a previously reported acceleration of sequence evolution of exon 7, which encodes domain D3, is driven by positive selection instead of neutral evolution. Irrespective of the …
Molecular diversity at the self-incompatibility locus is a salient feature in natural populations of wild tomato (Lycopersicon peruvianum)
1993
A cDNA encoding a stylar protein was cloned from flowers of self-incompatible wild tomato (Lycopersicon peruvianum). The corresponding gene was mapped to the S locus, which is responsible for self-incompatibility. The nucleotide sequence was determined for this allele, and compared to other S-related sequences in the Solanaceae. The S allele was used to probe DNA from 92 plants comprising 10 natural populations of Lycopersicon peruvianum. Hybridization was conducted under moderate and permissive stringencies in order to detect homologous sequences. Few alleles were detected, even under permissive conditions, underscoring the great sequence diversity at this locus. Those alleles that were de…
The Genetics of Evolutionary Change in Senecio vulgaris L.: A QTL Mapping Approach
2001
: The cosmopolitan weed Senecio vulgaris var. vulgaris is likely to have originated from the non-weedy S. vulgaris ssp. denticulatus from which it differs by showing no seed dormancy, by completing its life cycle from germination to seed formation much faster and by lacking ray florets. An F2 generation of 120 individuals obtained through selfing of one hybrid individual between var. vulgaris and ssp. denticulatus was used to construct a linkage map based on RAPD polymorphisms and the presence or absence of ray florets. This linkage map was used for a QTL analysis of 12 characters distinguishing the two taxa. For seven of these 12 characters, three significant QTLs could be found. One of th…
Interphase FISH assays for the detection of translocations with breakpoints in immunoglobulin light chain loci
2002
Many B-cell malignancies bear chromosomal translocations juxtaposing immunoglobulin (IG) genes with oncogenes, resulting in deregulated expression of the latter. Translocations affecting the IG heavy chain (IGH) locus in chromosomal region 14q32 are most prevalent. However, variant translocations involving the IG kappa (IGK) locus in 2p12 or the IG lambda (IGL) locus in 22q11 occur recurrently in B-cell neoplasias. No routine methods for the detection of all breakpoints involving IG light chain loci independently of the translocation partner have been described. For this reason, we have designed 2 novel interphase fluorescence in situ hybridization (FISH) assays using differentially labeled…
The mouseClq genes are clustered on chromosome 4 and show conservation of gene organization
1996
Mouse complement component C1q is a serum glycoprotein which consists of six A chains, six B chains and six C chains. The three polypeptides are 223, 228, and 217 residues long, respectively, and are encoded by three genes. DNA probes for mouse C1q A, B, and C chains were hybridized to Southern blots of DNA obtained from various inbred mouse strains. On the basis of fragment length polymorphisms, two different alleles of each of the genes could be identified. The distribution of these alleles was determined in the BXD and LXPL recombinant inbred strain series. Comparison with previously reported strain distribution patterns shows that the genes encoding mouseClq map to the same locus on dis…
Analysis of extended genomic rearrangements in oncological research.
2007
Screening for genomic rearrangements is a fundamental task in the genetic diagnosis of many inherited disorders including cancer-predisposing syndromes. Several methods were developed for analysis of structural genomic abnormalities, some are targeted to the analysis of one or few specific loci, others are designed to scan the whole genome. Locus-specific methods are used when the candidate loci responsible for the specific pathological condition are known. Whole-genome methods are used to discover loci bearing structural abnormalities when the disease-associated locus is unknown. Three main approaches have been employed for the analysis of locus-specific structural changes. The first two a…
Copy Number Variation and Missense Mutations of the Agouti Signaling Protein (<i>ASIP)</i> Gene in Goat Breeds with Different Coat Colors
2009
In goats, classical genetic studies reported a large number of alleles at the <i>Agouti</i> locus with effects on coat color and pattern distribution. From these early studies, the dominant <i>A</i><sup>Wt</sup> (white/tan) allele was suggested to cause the white color of the Saanen breed. Here, we sequenced the coding region of the goat <i>ASIP</i> gene in 6 goat breeds (Girgentana, Maltese, Derivata di Siria, Murciano-Granadina, Camosciata delle Alpi, and Saanen), with different coat colors and patterns. Five single nucleotide polymorphisms (SNPs) were identified, 3 of which caused missense mutations in conserved positions of the cysteine-ri…
Analysis of the melanocortin receptor 1 (MC1R) gene in Sicilian goat breeds
2010
AbstractMammalian coat colour is mainly determined by the distribution of two different types of melanins: pheomelanin (red/yellow pigments) and eumelanin (black pigments). Their synthesis is regulated by the melanocortin 1 receptor (MC1R/Extension locus) that binds the α-melanocyte-stimulating hormone (α-MSH) and the agouti signalling protein (ASIP, coded by the Agouti locus). In mammals, several studies have reported that loss-of-function mutations in MC1R lead to red/yellow pigmentation, while gain-of-function mutations lead to black/dark colours. Mutations at the Agouti locus exert, in general, epistatic interactions on the Extension locus. In goats, classical genetic studies have indic…
Coat colours in the Massese sheep breed are associated with mutations in the agouti signalling protein (ASIP) and melanocortin 1 receptor (MC1R) genes
2012
Massese is an Italian dairy sheep breed characterized by animals with black skin and horns and black or apparent grey hairs. Owing to the presence of these two coat colour types, this breed can be considered an interesting model to evaluate the effects of coat colour gene polymorphisms on this phenotypic trait. Two main loci have been already shown to affect coat colour in sheep: Agouti and Extension coding for the agouti signalling protein (ASIP) and melanocortin 1 receptor (MC1R) genes, respectively. The Agouti locus is affected by a large duplication including the ASIP gene that may determine the Agouti white and tan allele (A(Wt)). Other disrupting or partially inactivating mutations ha…