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Centromeric End (centromeric + end)
Selected AbstractsLRRN6A/LERN1 (leucine-rich repeat neuronal protein 1), a novel gene with enriched expression in limbic system and neocortexEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 12 2003Laura Carim-Todd Abstract Human chromosome 15q24-q26 is a very complex genomic region containing several blocks of segmental duplications to which susceptibility to anxiety disorders has been mapped (Gratacos et al., 2001, Cell, 106, 367,379; Pujana et al., 2001, Genome Res., 11, 98,111). Through an in silico gene content analysis of the 15q24-q26 region we have identifie1d a novel gene, LRRN6A (leucine-rich repeat neuronal 6A), and confirmed its location to the centromeric end of this complex region. LRRN6A encodes a transmembrane leucine-rich repeat protein, LERN1 (leucine-rich repeat neuronal protein 1), with similarity to proteins involved in axonal guidance and migration, nervous system development and regeneration processes. The identification of homologous genes to LRRN6A on chromosomes 9 and 19 and the orthologous genes in the mouse genome and other organisms suggests that LERN proteins constitute a novel subfamily of LRR (leucine-rich repeat)-containing proteins. The LRRN6A expression pattern is specific to the central nervous system, highly and broadly expressed during early stages of development and gradually restricted to forebrain structures as development proceeds. Expression level in adulthood is lower in general but remains stable and significantly enriched in the limbic system and cerebral cortex. Taken together, the confirmation of LRRN6A's expression profile, its predicted protein structure and its similarity to nervous system-expressed LRR proteins with essential roles in nervous system development and maintenance suggest that LRRN6A is a novel gene of relevance in the molecular and cellular neurobiology of vertebrates. [source] Identification of novel single nucleotide polymorphisms within the NOTCH4 gene and determination of association with MHC allelesINTERNATIONAL JOURNAL OF IMMUNOGENETICS, Issue 2 2003R. Tazi-Ahnini Summary Mapping of disease susceptibility loci within the MHC has been partly hampered by the high degree of polymorphism of the HLA genes and the high level of linkage disequilibrium (LD) between markers within the MHC region. It is therefore important to identify new markers and determine the level of LD between HLA alleles and non-HLA genes. The NOTCH4 gene lies at the centromeric end of the MHC class III region, approximately 335 kb telomeric of the DRB1 locus. The encoded protein is an oncogene that is important in regulating vascular development and remodelling. A recent report has linked polymorphisms within NOTCH4 with risk of developing schizophrenia. We have investigated if coding polymorphisms exist within this gene and have identified three single nucleotide polymorphisms; a synonomous T to C transition at +1297 (HGBASE accession number SNP000064386), a synonomous A to G transition at +3061 (SNP000064387) and an A to G transition at +3063 which results in a replacement of glycine with aspartic acid at amino acid 279 (SNP000064388). The allele frequencies of +1297T, +3061A and +3063G were 0.65, 0.66 and 0.66, respectively. Linkage disequilibrium was detected both between these markers and with MHC alleles. These findings can be used in the fine mapping of disease susceptibility alleles within the MHC. [source] Assessment of selection mapping near the myostatin gene (GDF-8) in cattleANIMAL GENETICS, Issue 5 2009P. Wiener Summary Domestic species provide a unique opportunity to examine the effects of selection on the genome. The myostatin gene (GDF-8) has been under strong selection in a number of cattle breeds because of its influence on muscle conformation and association with the ,double-muscling' phenotype. This study examined genetic diversity near this gene in a set of breeds including some nearly fixed for the allele associated with double-muscling (MH), some where the allele is segregating at intermediate frequency and some where the allele is absent. A set of microsatellites and SNPs were used to examine patterns of diversity at the centromeric end of bovine chromosome 2, the region where GDF-8 is located, using various statistical methods. The putative position of a selected gene was moved across the genomic region to determine, by regression, a best position of reduced heterozygosity. Additional analyses examined extended homozygous regions and linkage disequilibrium patterns. While the SNP data was not found to be very informative for selection mapping in this dataset, analyses of the microsatellite data provided evidence of selection on GDF-8 in several breeds. These results suggested that, of the breeds examined, the allele was most recently introduced into the South Devon. Limitations to the selection-mapping approach were highlighted from the analysis of the SNP data and the situation where the MH allele was at intermediate frequency. [source] Bovine umbilical hernia maps to the centromeric end of Bos taurus autosome 8ANIMAL GENETICS, Issue 6 2004M. Ron Summary Twelve bull calves were produced by mating elite Israeli cows to ,Glenhapton Enhancer', a Canadian Holstein bull. The frequency of umbilical hernia (UH) in the progeny of the sons ranged from 1 to 21%, consistent with the hypothesis that Enhancer is the carrier of major dominant or codominant gene with partial penetrance for UH. Five sons of Enhancer produced progeny with >10% frequency of UH including sire 3259, whereas progeny of three sons had <3% UH. A total of 116 grand-progeny of Enhancer, all progeny of 3259, were genotyped for 59 microsatellites spanning the 29 bovine autosomes. Of these offspring, 41 were affected. Significant differences in paternal allele frequencies between the affected and unaffected progeny groups were found for marker BMS1591 on bovine chromosome 8 (BTA8). The UH-associated paternal allele originated from Enhancer. The chromosomal segment associated with UH was more precisely mapped between UWCA47, on the centromeric end of BTA8 and RM321, 12 cM from the centromere. A maximum LOD score of 3.84 was obtained 2.5 cM from the centromere with a support interval of 8 cM. Haplotype analysis of eight sons of Enhancer suggested that the UH gene is located in the centromeric end of BTA8 beyond ARO71/ARO72. Thus, by integrating the results from progeny of sire 3259 and sons of Enhancer the location of the UH gene was further refined to the BTA8 segment between ARO71/ARO72 and UWCA47. [source] | ||||||||||