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At least 1,135 records · Page 63Linked to original sources
PubMed1995

Genetic map of the Mycoplasma genitalium chromosome.

At 600 kb, the genome of Mycoplasma genitalium is among the smallest known for cellular organisms capable of independent replication. As such, elucidation of the genetic makeup and chromosome architecture of this organism is of considerable interest. We have located 631 markers on the physical map of M. genitalium. The clones have been mapped by hybridizing 20 overlapping cosmid and lambda clones which encompass the entire M. genitalium chromosome to replica filters containing 856 genomic DNA clones. Three hundred fifty-six of these clones represent sequence tag sites, which were previously characterized by database searches. The remaining markers represent clones with an average size of 2.5 kb derived from Sau3A1 partial digestion of genomic DNA. The hybridization data can be divided into three classes: clones which hybridized to only one cosmid; clones which hybridized to two adjacent and overlapping cosmids; and clones which hybridized to several cosmids, which represent repetitive DNA. This rapid approach for placing clones on the physical map has allowed useful comparisons to be made with other bacterial chromosomes, especially that of the closely related organism M. pneumoniae, and has provided insight to the types of events which may have led to the reduction in size of this genome. Future use of these data is discussed.

Chromosome Mapping↗
PubMed2005

Genetic mapping of expressed sequences in onion and in silico comparisons with rice show scant colinearity.

The Poales (which include the grasses) and Asparagales [which include onion (Allium cepa L.) and other Allium species] are the two most economically important monocot orders. Enormous genomic resources have been developed for the grasses; however, their applicability to other major monocot groups, such as the Asparagales, is unclear. Expressed sequence tags (ESTs) from onion that showed significant similarities (80% similarity over at least 70% of the sequence) to single positions in the rice genome were selected. One hundred new genetic markers developed from these ESTs were added to the intraspecific map derived from the BYG15-23xAC43 segregating family, producing 14 linkage groups encompassing 1,907 cM at LOD 4. Onion linkage groups were assigned to chromosomes using alien addition lines of Allium fistulosum L. carrying single onion chromosomes. Visual comparisons of genetic linkage in onion with physical linkage in rice revealed scant colinearity; however, short regions of colinearity could be identified. Our results demonstrate that the grasses may not be appropriate genomic models for other major monocot groups such as the Asparagales; this will make it necessary to develop genomic resources for these important plants.

Base Sequence↗
PubMed1986

Characterization and genetic mapping of a mutation affecting apurinic endonuclease activity in Staphylococcus aureus.

Protoplast fusion between the Rec- mutant RN981 (L. Wyman, R. V. Goering, and R. P. Novick, Genetics 76:681-702, 1974) of Staphylococcus aureus NCTC 8325 and a Rec+ NCTC 8325 derivative yielded Rec+ recombinants that exhibited the increased sensitivity to N-methyl-N'-nitro-N-nitrosoguanidine characteristic of RN981. Transformation analyses identified a specific mutation, designated ngr-374, that was responsible not only for N-methyl-N'-nitro-N-nitrosoguanidine sensitivity, but also sensitivity to methyl methanesulfonate, ethyl methanesulfonate, nitrous acid, and UV irradiation. However, ngr-374-carrying recombinants showed no significant increase in their sensitivity to mitomycin C or 4-nitroquinoline 1-oxide and were unaffected in recombination proficiency. In vitro assays showed that ngr-374-carrying strains had lower apurinic/apyrimidinic endonuclease activities than the wild type. The chromosomal locus occupied by ngr-374 was shown to exist in the gene order omega(Chr::Tn551)40-ngr-374-thrB106.

4-Nitroquinoline-1-oxide↗
PubMed1989

Construction of a linkage map of the human genome, and its application to mapping genetic diseases.

A powerful method for localizing the genes responsible for genetic diseases is to "mark" each chromosomal region so as to permit its inheritance to be tracked in families carrying the disease; the disease gene must lie in the same region as any marker with which it is co-inherited. Chromosomes can be efficiently marked in this way by using restriction fragment length polymorphisms (RFLPs). We describe the construction of a map of the human genome with over 550 RFLP markers, such that over 95% of the genome is detectably linked to one or more of these markers. This map will make possible efficient searches for genes underlying a variety of disorders, both simple and complex, and lead to the development of presymptomatic diagnostic tests for these diseases.

Base Sequence↗
PubMed1994

Genetic mapping of the Batten disease locus (CLN3) to the interval D16S288-D16S383 by analysis of haplotypes and allelic association.

CLN3, the gene for juvenile-onset neuronal ceroid lipofuscinosis (JNCL) or Batten disease, has been localized by genetic linkage analysis to chromosome 16p between loci D16S297 and D16S57. We have now further refined the localization of CLN3 by haplotype analysis using two new microsatellite markers from loci D16S383 and SPN in the D16S297-D16S57 interval on a larger collaborative family resource consisting of 142 JNCL pedigrees. Crossover events in 3 maternal meioses define new flanking markers for CLN3 and localize the gene to the interval at 16p12.1-p11.2 between D16S288 and D16S383, which corresponds to a genetic distance of 2.1 cM. Within this interval 4 microsatellite loci are in strong linkage disequilibrium with CLN3, and extended haplotype analysis of the associated alleles indicates that CLN3 is in closest proximity to loci D16S299 and D16S298.

Alleles↗
PubMed1996

A pericentric inversion of chromosome six in a patient with Peutz-Jeghers' syndrome and the use of FISH to localise the breakpoints on a genetic map.

Karyotypic analysis in a patient with Peutz-Jeghers' syndrome demonstrated a pericentric inversion on chromosome 6. Further investigation was undertaken using fluorescence in situ hybridisation (FISH) with yeast artificial chromosome clones selected to contain genetic markers from chromosome 6, and a probe for the centromeric alphoid repeat array. This analysis located one inversion breakpoint within the alphoid array, in a 1-cM interval between D6S257 and D6S402, and the other in a 4-cM interval between D6S403 and D6S311. The oestrogen receptor gene locus (ESR) is excluded from the latter interval.

Adult↗
PubMed2003

Genetic mapping of the Sorghum bicolor vp1 gene and its relationship with preharvest sprouting resistance.

The plant vp1 gene encodes a transcription factor originally identified in maize that participates in the control of the transition from embryogenesis to seed germination. Different lines of evidence suggest that vp1 participates in preharvest sprouting (PHS) resistance in cereals, but the genetic relationship is not yet established. Thus, the aim of this study was to investigate if there is a connection between vp1 and the formerly documented quantitative trait loci for PHS in Sorghum bicolor. This gene was mapped in sorghum using two well-studied inbred lines displaying contrasting PHS phenotypes. Linkage analysis revealed that the S. bicolor vp1 (Sbvp1) locus is linked to markers located on chromosomes 3 and 8 in maize. Analysis indicated that this gene is not correlated with PHS at a statistically significant level. Structural analysis of the Sbvp1 gene from both inbred lines showed a high degree of overall conservation (low polymorphism), even in the promoter region. These findings, taken together with the previously observed correlation between the pattern of expression of this gene and PHS performance, suggest that Sbvp1 might act downstream in the signalling pathway that leads to seed germination, or even be differentially regulated as a consequence rather than as a cause of the phenotypic behaviour.

Chromosome Mapping↗
PubMed1999

Genetic mapping of the rat Lcn2 gene to chromosome 3.

The expression of rat 24p3, encoded by the Lcn2 gene, has been associated with rat mammary carcinomas initiated by the neu oncogene (Stoesz and Gould, 1995). In this study, we assign the Lcn2 gene to rat chromosome band 3q12 by genetic linkage analysis.

Acute-Phase Proteins↗
PubMed1994

Genetic map of the fused locus on mouse chromosome 17.

Fused (Fu) is a dominant mutation in mice resulting in the asymmetry and fusion of tail vertebrae in heterozygotes. Fu/Fu homozygotes are often viable and can exhibit a duplication of the terminal tail vertebrae resulting in bifurcated tails. There are two more severe alleles at Fu, Kinky (FuKi) and Knobbly (FuKb), which die between 9 and 10 days of gestation as homozygotes, exhibiting a duplication of the embryonic axis, leading to incomplete or complete twinning. To define the precise map position of the FuKi mutation on mouse Chromosome 17, a 983-animal (FuKi tf x Mus spretus)F1 x +tf/+tf interspecific backcross was generated and scored for FuKi, another tightly linked visible marker tufted (tf), and five linked molecular loci, D17MIT18, D17Leh54, D17Aus57, Hba-ps4, and Pim1. The order and genetic distances between the markers were determined to be centromere-D17MIT18-5.79 cM-D17Leh54-0.85 cM-D17Pri6-0.12 cM-D17Pri7-0.12 cM-Hba-ps4-1.20 cM-D17Pri8-0.48 cM-tf-2.05 cM-Pim1. The FuKi gene could not be genetically separated from three molecular markers, D17Pri6, D17Pri7, and Hba-ps4. Yeast artificial chromosome clones that contain these tightly linked markers have been isolated to form a contig that contains FuKi. Recombination breakpoints generated through the interspecies backcross were mapped onto the contig and demonstrate that recombination in this region is not random.

Animals↗
PubMed1993

Genetic mapping of three GABAA receptor-subunit genes in the mouse.

GABAA receptors are a heterogeneous group of heterooligomeric ligand-gated anion channels that represent the main means of synaptic inhibition in neuronal tissue. At least 14 distinct GABAA subunit proteins representing 5 different classes have been identified. Using rat brain cDNAs for the GABAA receptor beta 1-, alpha 2-, and alpha 4-subunits, we have assigned the corresponding murine genes Gabrb-1, Gabra-2, and Gabra-4 to specific chromosomes with somatic cell hybrids, and we have positioned these genes by analysis of the progeny of three genetic crosses. Gabrb-1 and Gabra-2 are tightly linked on mouse Chromosome 5 between the markers Pgm-1 and Kit, and Gabra-4 maps to proximal mouse Chromosome 7 in apparent proximity to the previously mapped Gabrb-3. The Gabrb-1, Gabra-2 pair of genes on Chr 5 maps near the mouse "circling mutation" pi (pirouette).

Alleles↗
PubMed2002

Genetic mapping of polyphenol oxidase in tetraploid wheat.

Pasta colour is one of the main factors influencing pasta quality. It is the product of a desirable yellow component, an undesirable brown component and, under some drying conditions, a red component. The brown colour depends on enzymatic and chemical factors. Polyphenol oxidase (PPO; E.C. 1.14.18.1) is one of the enzymatic factors. It is mainly localised in the peripheral part of the wheat kernel, and is involved in the oxidation of endogenous wheat phenolic compounds resulting in the production of highly coloured products. Therefore, a knowledge of the genetic control of PPO activity could enable the developing of better strategies in breeding programs to reduce pasta darkening. The aim of this study was to map the gene(s) affecting PPO activity using a set of recombinant inbred (RI) lines, derived from a cross between Triticum turgidum L. var. durum cultivar Messapia and the accession MG4343 of Triticum turgidum L. var. dicoccoides. After performing linkage analysis, the gene for high PPO activity was mapped on the long arm of the chromosome 2A and its characteristic was found highly associated to the RFLP marker Xutv1427-2A, with a value of LOD equal to 29.84. The identification of molecular markers linked to loci controlling the PPO activity may potentially accelerate wheat breeding since the selection of plants can be carried out by genotype rather than phenotype.

Breeding↗
PubMed1992

Genetic mapping of 1,3-beta-glucanase-encoding genes in Saccharomyces cerevisiae.

The map position of three 1,3-beta-glucanase-encoding genes in S. cerevisiae has been determined following conventional meiotic and mitotic mapping combined with recombinant DNA techniques. EXG1, EXG2 and SSG1 were localized to chromosomes XII, IV and XV, respectively, by hybridizing the cloned genes to Southern blots of chromosomes separated by pulsed-field gel electrophoresis, in conjunction with the rad52-1-dependent chromosome-loss mapping technique. Meiotic tetrad analyses further localized the EXG1 gene 6.1 centimorgans centromere-proximal to CDC25 on the right arm of chromosome XII. EXG2 was positioned between LYS4 and GCN2 on the right arm of chromosome IV, at distances of 6.2 centimorgans from LYS4 and 4.9 centimorgans from GCN2. Finally, the SSG1 locus mapped on the right arm of chromosome XV, about 8.2 centimorgans to the centromere-proximal side of HIS3.

Chromosome Mapping↗
PubMed1979

Genetic mapping of the region c of the bacteriophage G101 (Pseudomonas aeruginosa).

Morphological mutants of the c type of the bacteriophage G101 (Pseudomonas aeruginosa) were isolated after mutagenesis with hydroxylamine. Complementation analysis of 27 c mutants showed that the c region is formed by at least two genes. Two types of c mutants were obtained. One of them (cI26) behaves analogously to a mutant in the gene controlling the synthesis of the repressor of phage lambda. The second type of the c mutants (cII1, cII18) specifies a gene having probably an auxiliary function in the "c" region. According to the low frequency of recombination between the genes cI26 and c II18 (1.37 recombination units), these genes responsible for lysogenization are localized in a short region of the chromosome.

Bacteriophages↗
PubMed1996

Genetic mapping of genes for twelve nuclear-encoded polypeptides associated with the thylakoid membranes in Beta vulgaris L.

Thylakoid membranes of chloroplasts are composed of approx. 75 polypeptide species. Nearly 60% originate in nuclear genes, the remainder in plastid genes. In order to localize representatives of the nuclear-encoded gene complement in a eukaryotic plant genome (sugar beet, Beta vulgaris L.), we have investigated the RFLP patterns of 21 cDNAs from spinach that code for thylakoid proteins or proteins peripherally associated with thylakoid membranes. Differences in gene dosage were noted between both related species. Polymorphism was found for 12 cDNA loci in a segregating sugar beet F2 population. These loci were mapped along with genomic RFLP, isozyme, and morphological markers, and shown to be distributed in six of the nine sugar beet linkage groups. The lack of positional clustering even of genes that encode components of the same supramolecular membrane assembly is commensurate with phylogenetically independent gene translocations from the plastid (endosymbiont), and raises the question of the functional integration of various translocated genes into common signal transduction chains.

Cell Nucleus↗
PubMed1993

HLA susceptibility genes in celiac disease: genetic mapping and role in pathogenesis.

The overrepresentation of particular HLA alleles in patients with celiac disease was first noted two decades ago. Several lines of evidence obtained during the last years strongly suggest that a particular HLA-DQ heterodimer, encoded by the DQA1*0501 and DQB1*0201 genes in cis or trans configuration, confers the primary disease susceptibility. This paper reviews the evidence behind this concept and discusses how this particular DQ molecule may be involved in the pathogenesis.

Alleles↗