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At least 739 records · Page 41Linked to original sources
PubMed1994

Analysis of segregation in a human male reciprocal translocation carrier, t(1;11) (p36.3;q13.1), by two-colour fluorescence in situ hybridization.

Using centromeric probes specific for chromosomes 1 and 11, 13,071 sperm nuclei from a male reciprocal translocation heterozygote, 46,XY,t(1;11) (p36.3;q13.1), were analyzed by fluorescence in situ hybridization (FISH). Decondensed sperm nuclei were simultaneously hybridized with DNA probes for chromosome 1 (pUC177) and chromosome 11 (D11Z1). Results were as follows: 1/11 (82.45%), 1/1/- (3.45%), -/11/11 (4.85%), 1/1/11 (1.20%), 1/11/11 (1.14%), 1/- (4.33%), -/11 (2.50%), 1/1/11/11 (0.06%), 1/1/1/- (0.02%). Because both the normal chromosome and its translocated derivative carry the same centromeric sequences, FISH cannot differentiate between sperm resulting from alternate segregation and those produced by adjacent I segregation. Using the same donor, comparable segregation patterns were obtained from sperm chromosome karyotypes (Spriggs et al., 1992: Hum Genet 88:447-452) and from MII spermatocytes (Goldman and Hulten, 1993: Cytogenet Cell Genet 63:16-23), demonstrating that selection is not a factor in the human sperm/hamster oocyte fusion technique or during meiosis. Although FISH does not provide the detailed information afforded by sperm karyotyping, it is a valuable technique for studying segregation patterns in translocation heterozygotes.

Cell Nucleus↗
PubMed2006

Inheritance and mapping of a powdery mildew resistance gene introgressed from Avena macrostachya in cultivated oat.

The powdery mildew resistance from Avena macrostachya was successfully introgressed into hexaploid oat (A. sativa). Genetic analysis of F(1), F(2), F(3) and BC(1) populations from two powdery-mildew resistant introgression lines revealed that the resistance is controlled by a dominant gene, tentatively designated Eg-5. Molecular marker analysis was conducted using bulked-segregant analysis in two segregating F(3) populations. One codominant simple sequence repeats (SSR) marker AM102 and four AFLP-derived PCR-based markers were successfully developed. The SSR marker AM102 and the STS marker ASE41M56 were linked to the gene Eg-5, with genetic distances of 2 and 0.4 cM, respectively, in both mapping populations. Three STS markers (ASE45M56, ASE41M61, ASE36M55) co-segregated with Eg-5 in one population while two (ASE45M56, ASE36M55) of them linked to Eg-5 with a genetic distance of 1 cM in another population. The gene was further mapped to be in a region corresponding to linkage group 22_44+18 in the Kanota x Ogle (KO) hexaploid oat map by comparative mapping. To our knowledge, this is the first report of mapping powdery-mildew resistance in hexaploid oat. The new resistance source of A. macrostachya, together with the tightly linked markers identified here, could be beneficial in oat breeding programmes.

Ascomycota↗
PubMed2001

Identification of a BIBAC clone that co-segregates with the petunia restorer of fertility (Rf) gene.

Molecular markers closely linked to the Restorer of fertility (Rf) locus in petunia were sought by conducting a bulk segregant analysis. The co-segregation of markers and Rf was tested on a large BC1 population produced from two different parental lines carrying Rf. The recombination frequency between OP704 and ECCA/MACT, the two most distal markers utilized in the fine-scale mapping. was significantly different in populations derived from parents that carry different nuclear backgrounds. The fine mapping identified an amplified fragment length polymorphism (AFLP) marker that co-segregates with Rf. A petunia BIBAC library (four genome equivalents), with an average insert size of 70 kb, was constructed and screened with the linked marker. A contiguous map was constructed from three different BIBAC clones that hybridized to the marker. As a result, we have identified a 37.5-kb BIBAC clone that co-segregates with Rf.

Chromosome Mapping↗
PubMed1999

Analysis of segregation and aneuploidy in two reciprocal translocation carriers, t(3;9)(q26.2;q32) and t(3;9)(p25;q32), by triple-color fluorescence in situ hybridization.

Meiotic segregation patterns of chromosomes 3 and 9 were analyzed in sperm of two translocation carriers (t(3;9)(q26.2;q32) and t(3;9)(p25;q32)) by triple-color fluorescent in situ hybridization (FISH) with a telomeric DNA probe in addition to two centromeric probes. The frequencies of each sperm product resulting from alternate or adjacent I, adjacent II and 3:1 segregation in a t(3;9)(q26.2;q32) translocation carrier were 88.35%, 5.44% and 5.94%, respectively. On the other hand, the frequencies of each sperm product in a t(3;9)(p25;q32) translocation carrier were 89.23%, 6.02% and 4.48%, respectively. Of all the sperm products, the frequency of normal or chromosomally balanced sperm in a t(3;9)(q26.2;q32) and a t(3;9)(p25;q32) were 52.49% and 47.25%, respectively. The frequencies of each sperm product resulting from various segregations were different between both carriers and significantly deviated from the expected frequencies. Additional dual-color and triple-color FISH were performed to analyze aneuploidy rates for chromosomes 12, 17, 18, X and Y in order to detect any interchromosomal effect; no evidence of an interchromosomal effect was found.

Abortion, Habitual↗
PubMed1983

A genetic map of reovirus: assignment of the newly defined mutant groups H, I, and J to genome segments.

Mutants representing three previously undefined reovirus type 3 mutant groups have been isolated following backcross of suppressed pseudorevertants to wild type (R.F. Ramig and B.N. Fields, 1979, Virology 92, 155-167; R. Ahmed, P.R. Chakraborty, A.F. Graham, R.F. Ramig, and B.N. Fields, 1980, J. Virol. 34, 383-389). The prototype mutant of each of the three new mutant groups was mapped by analysis of genome segment segregation in intertypic recombinants derived from crosses between the type 3 ts mutants and ts mutants of type 1 or type 2. Segregation analysis revealed the location of the group H prototype mutant tsH(26/8) to be genome segment M1, that of the group I prototype mutant tsI(138) to be segment L3, and that of the group J prototype mutant tsJ(128) to be segment S1. Mapping of the group I and J lesions required the identification of suppressed ts lesions in some of the intertypic rcombinant clones.

Animals↗
PubMed2006

The complete sequence and segregational stability analysis of a new cryptic plasmid pIGWZ12 from a clinical strain of Escherichia coli.

A new cryptic plasmid from a multi-resistant, multi-plasmid clinical strain of Escherichia coli has been isolated. The sequence of the 4072-base-pair pIGWZ12 (GenBank Accession No. DQ311641) was determined and analyzed. Two open-reading frames that code for proteins involved in plasmid mobilization and initiation of replication were identified. The putative origin of replication possesses all characteristic features of the theta mechanism for replicating plasmids. pIGWZ12 is stably maintained without selective pressure in bacterial cultures (for up to 80 generations), making it a good candidate for engineering a new cloning vector.

Amino Acid Sequence↗
PubMed2001

The role of interacting determinants in the localization of genes.

We describe the potential gains in power for localizing disease genes that can be obtained by allowing for interactions with environmental agents or other genes. The focus is on linkage and association methods in nuclear families with dichotomous phenotypes. A logistic model incorporating various main effects and interactions is used for penetrance, but similar methods apply to censored age-at-onset or continuous phenotypes. We begin by discussing the influence of gene-environment interactions in segregation analysis, illustrated with analysis of smoking as a modifying factor for lung cancer. We then discuss a number of approaches to linkage analysis-model-free and model-based(including generalized estimating equations) incorporating interactions with environmental factors and other genes, either candidate genes or linked loci. We find that a test of heterogeneity in IBD sharing probabilities across strata defined by sharing of environmental factors can offer greater power for detecting linkage than the simple mean test, provided the interaction effect is sufficiently strong; we explore the conditions under which this gain in power occurs. Finally, we describe approaches for testing association and disequilibrium involving interactions, utilizing case-control, case-parent, and pedigree-based approaches. A technical problem that must be addressed in many analyses is the effect of missing data on environmental covariates; we use multiple imputation in an analysis of lung cancer segregation to illustrate an approach to this problem.

Carcinogens, Environmental↗
PubMed2006

Analysis of segregation distortion of molecular markers in F2 population of rice.

A genetic linkage map comprising 148 SSR markers loci was constructed using an F2 population consisting of 90 lines derived from a sub-specific cross between a japonica variety Nipponbare and an indica variety Guangluai-4. The F2 population showed high significantly distorted segregations. Among these SSR markers, 49 markers(33.11%) showed the genetics distortion(P<0.05). Of them, 36 markers deviated toward male parent indica GuangLuAi-4 and 13 markers toward heterozygote, but none toward the female parent Nipponbare. It was found that the segregation distortion might be caused by gametophyte and zygote. Since most gametophyte loci and sterility loci were mapped in segregation distortion regions, it indicated that the segregation distortion may be caused by these gametophyte loci and sterility loci. Finally, this research also analyzed the skewed segregation of some markers, which had not been mapped on chromosome.

Biomarkers↗
PubMed2002

Bovine abnormal preimplantation embryos: analysis of segregated cells occurring in the subzonal space and/or blastocoele cavity for their nuclear morphology and persistence of RNA synthesis.

Bovine embryos in the early blastocyst/blastocyst stage were analysed by [5-3H]uridine labelling followed by electron microscopic autoradiography. In normal control embryos an intact zona pellucida, evenly developed blastomeres and a transparent perivitelline space were seen. In this group, the blastomeres of the trophoblast and embryoblast showed high homogeneous labelling localised in the nucleoplasm and even more intense labelling in the nucleolus. On the contrary, in addition to evident cytoplasmic disintegration, a clearly different labelling pattern and a low labelling intensity were observed in the nuclei of the segregated cells in the subzonal space and in those free in the blastocoele cavity. A typical nuclear morphological feature of these blastomeres was chromatin marginalisation, similar to that observed in embryos treated with actinomycin D for transcription inhibition. It is concluded that the segregated cells are arrested in their further differentiation.

Animals↗
PubMed2000

Development of a PCR-SSOP approach capable of defining the natural killer cell inhibitory receptor (KIR) gene sequence repertoires.

A molecular typing method based on polymerase chain reaction (PCR) amplification of three different target domains (immunoglobulin domains 1 and 3, and the transmembrane-cytoplasmic domain), followed by hybridisation with 26 digoxigenin-labelled sequence-specific oligonucleotide probes (SSOP) has been established for the polymorphic killer inhibitory receptor (KIR) genes. In addition to identifying the 12 KIR subfamilies, our PCR-SSOP typing approach could also distinguish the putative alleles, NKB1 and NKAT3, that comprise the KIR3DL1 subfamily. Ninety unrelated blood donors and 13 families (52 individuals), including both parents, were subjected to our KIR PCR-SSOP typing approach. All 12 KIR subfamilies, including a 2DS5 variant sequence, were present in the 90 individuals and displayed varied phenotype frequencies: 2DL1 (0.96), 2DL2 (0.31), 2DL3 (0.95), 2DS1 (0.56) 2DS2 (0.51), 2DS3 (0.27), 2DS4 (0.96), 2DS5v (0.35), 3DS1 (0.47), 3DL1 (0.96), 3DL2 (1.0) and 2DL4 (1.0). A total of 23 different KIR phenotypes were defined in this study, and 10 of these were only found on one occasion in one individual, indicating considerable diversity in the KIR phenotype profiles within the Irish population. Most individuals (93%) possessed the complement of inhibitory KIR specificities for the three well-defined HLA-B and -C ligands. An unusual probe pattern for 3DS1 was observed in 3 individuals indicating a variant 3DS1 gene sequence with changes at nucleotide positions 1185-1186, within the cytoplasmic domain. Sequencing analysis revealed a new single nucleotide polymorphism in exon 3 of 3DL1 NKB1(195, G-A) and a 22-bp deletion polymorphism in exon 5 of 2DS4 (nucleotides 777-798 deleted). A number of strong KIR associations were observed, namely 2DL1 with 2DL3, 2DS4 with 3DL1, 2DL2 with 2DS1/2DS2/2DS3, 2DS1 with 2DS3/2DS5v/3DS1, 2DS2 with 2DS3 and 2DS5v with 3DS1. Analysis of the KIR segregation observed in the 13 families confirmed these strong associations and permitted the definition of a number of partial KIR haplotypes, e.g. 2DL2-2DS1-2DS2-2DS3-3DL1. The segregation analysis concluded that at least 3 distinct gene loci encode 2DL1-4 and at least 4 gene loci encode the non-inhibitory KIR2DS1-2DS5. In the case of 3DL1-2 and 3DS1, our data suggests 3 gene loci, one for each subfamily.

Humans↗
PubMed2001

Analysis of segregation data from selfed progeny of allopolyploids.

This paper discusses the inference of parental genotype based on segregation data from selfed progeny of allopolyploids when there is incomplete information about genotypes and when alleles are codominant or null. The distinct alleles that are present in a genotype are assumed to be known, but not the frequency with which they occur. These assumptions may be appropriate when genotypes are deduced from DNA or protein banding patterns on electrophoretic gels. A computer program, SELF, is described that can generate all possible parental genotypes and rank them on the basis of their agreement with the progeny data. The program caters for tetraploids, hexaploids and octoploids. The methods are illustrated using data from a study of the inheritance of isoenzymes in selfed progeny of octoploid strawberry cultivars.

Alleles↗
PubMed1997

Identification of the parental origin of polysomy in two 49,XXXXY cases.

The parental origin and mechanism of formation of polysomy X were studied in two polysomic cases, using four X-linked restriction fragment length polymorphisms, three (CA)n dinucleotide repeat sequences and one variable number tandem repeat (VNTR) locus as genetic markers. A nonradioactive technique based on the hybridization of the polymerase chain reaction (PCR) product was developed for the analysis of dinucleotide repeats. Segregation analysis using different nonradioactive approaches based on the PCR, revealed that all four X chromosomes were of maternal origin. These data provide additional evidence of an identical mechanism of successive nondisjunctions in maternal meiosis I and II.

Adult↗
PubMed1992

Smooth pursuit ocular motor dysfunction in schizophrenia: evidence for a major gene.

OBJECTIVE: Evidence suggests that poor eye tracking relates to genetically transmitted vulnerability for schizophrenia. The authors tested competing models for the genetic transmission of poor eye tracking in a search for major gene effects. METHOD: Samples from three studies (conducted in Minneapolis, New York, and Vancouver, B.C.) were pooled. Probands (N = 92) were diagnosed as schizophrenic by DSM-III criteria. Of the comparison subjects (N = 171), Vancouver patients were an epidemiologic first-episode group; at other sites unselected admitted patients were studied. First-degree relatives (N = 146) of 65 probands were also studied. Eye tracking was measured while subjects followed a horizontally moving, sinusoidally driven (0.4 Hz) spot of light on a screen. Performance was quantified by root mean square error. Data analysis was by complex segregation analysis (Bonney's class D regressive models). RESULTS: A single major gene is needed to account for poor eye tracking in schizophrenic patients and their relatives. This gene alone can explain about two-thirds of the variance in eye tracking performance. A single gene alone (regardless of dominance) will, however, not account for the data; polygenic factors are also required. CONCLUSIONS: Results support postulation of a single gene for ocular motor dysfunction, which may be a risk factor for schizophrenia. Eye tracking may be useful as a gene carrier test in genetic studies of schizophrenia.

Adolescent↗
PubMed2006

Illuminating cancer health disparities using ethnogenetic layering (EL) and phenotype segregation network analysis (PSNA).

BACKGROUND: Resolving cancer health disparities continues to befuddle simplistic racial models. The racial groups alluded to in biomedicine, public health, and epidemiology are often profoundly substructured. METHODS: EL and PSNA are computational assisted techniques that focus on microethnic group (MEG) substructure. RESULTS: Geographical variations in cancer may be due to differences in MEG ancestry or similar environmental exposures to a recognized carcinogen. Examples include breast and prostate cancers in the Chesapeake Bay region and Bight of Biafra biological ancestry, hypertension and stroke in the Carolina Coast region and Central African biological ancestry, and pancreatic cancer in the Mississippi Delta region and dietary/medicinal exposure to safrol from Sassafras albidum.

Cultural Diversity↗
PubMed1989

Inherited collagen disorders.

The investigation of the inherited matrix disorders has been an example of progress on two parallel fronts. Two decades of protein chemistry have provided detailed background information on the structure, if not the function, of collagen. This has been used to identify the likely candidate genes for analysis using DNA markers. Segregation analysis has in turn sorted out which diseases are caused by collagen gene mutations and which are not. This information is now concentrating effort on defining the mutations in the linked diseases and establishing linkages to other genes in the rest. Using the background structural information, efficient and specific strategies for rapidly identifying individual mutants are being designed. Best of all, prenatal diagnosis is now a reality for many parents faced with the prospect of having a severely crippled child.

Collagen↗