共查询到20条相似文献,搜索用时 31 毫秒
1.
Craig H. Warden Steven Stone Sally Chiu Adam L. Diament Pablo Corva Donna Shattuck Robyn Riley Steven C. Hunt Juliet Easlick Janis S. Fisler Juan F. Medrano 《Mammalian genome》2004,15(6):460-471
Our primary objective was to discover simplified mouse models corresponding to human obesity linkages. We used the B10.UW– H3b we Pax1un at/Sn (B10.UW) congenic strain, a subcongenic strain with a reduced UW strain donor region, and their C57BL/10SnJ background strain. The congenic and subcongenic UW strain donor regions are on mouse Chr 2. We measured body length [anal-nasal (AN) length], summed fat depot weights normalized for body weight (Adiposity Index, AI), and percentage of body weight that is lipid. The B10.UW congenic and subcongenic strains have significantly smaller AN lengths (p < 0.0001) and have a significantly lower AI and percentage of body weight as fat than the background strain (p < 0.0001). In an F2 intercross of the congenic and background strains, AN and AI were both linked to the distal half of the donor region with LOD scores greater than 19 and 5, respectively. F2 haplotypes identified a minimal region for AN linkage of 0.8 megabases (Mb) that is estimated to express four genes in the current Celera mouse genome assembly. We narrowed the most likely location of the obesity gene to 15 Mb whose homologous genes are all located on human Chr 20 in the region surrounding the centromere. Since a previous study identified human obesity linkage peaking near the centromere, then the B10.UW mice may exhibit obesity due to the homologous gene. 相似文献
2.
Y. X. Liu H. Z. Han Q. L. Wang L. Jiang S. L. Wang X. Y. Zhang Y. Liu Y. F. Wang Y. J. Liu H. J. Liu 《Journal of fish biology》2013,82(2):588-599
A set of 72 microsatellite markers distributed evenly among 24 linkage groups were selected from the published genetic linkage maps of Japanese flounder Paralichthys olivaceus. In two normal diploid full‐sib families, the test for Mendelian inheritance showed that genotypic segregation deviations were not significant at all analysed loci. To estimate microsatellite‐centromere map distances, four meiotic gynogenetic diploid lines were produced by the activation of eggs using UV irradiated sperm of red seabream Pagrus major and cold‐shock treatment to block the extrusion of the second polar body. Under the assumption of complete interference, 21 markers were located in the centromeric region, 39 in the telomeric region and the rest in the intermediate region of linkage groups. A total of 192 mitotic gynogenetic diploids from one spawn were identified by these markers. Genotype analysis showed that the number of homozygous individuals decreased as microsatellite‐centromere map distance increased on each linkage group. 相似文献
3.
Denise Marcou 《Molecular & general genetics : MGG》1979,173(3):299-305
Summary A mutant which increases second division segregation (SDS) frequency of locus 110 (linkage group VI) was isolated. It was called mei4 because of its meiotic deficiency. The present paper deals with its effect on meiotic recombination when heterozygous. mei4 then only acts on linkage group VI. The SDS frequencies were increased for all markers used, except locus 5 located very close to the centromere. This quasi general enhancement results exclusively in an enlargement of map distance on linkage group VI's proximal part. Crosses involving three mutant genes allowed to check that the distances on the distal part were constant. This is due to a real lack of crossover frequency modification in this region and not to a change of chiasma interference. Among the seven linkage groups of Podospora anserina, group VI exhibits several other particularities concerning meiotic recombination, especially a lower positive chiasma interference and a more regular crossover distribution, suggesting a particular recombination regulation.Laboratoire associé n0 86 du Centre National de la Recherche Scientifique 相似文献
4.
Summary In Brassica oleracea, the pollen-stigma interaction of self-incompatibility is controlled by a single genetically defined locus designated S. Molecular studies have identified two genes that are tightly linked to the classically defined S locus: The S-Locus Glycoprotein (SLG) gene and the S-Receptor Kinase (SRK) gene. In previous RFLP linkage analyses with probes specific for SLG and SRK, we were unable to identify any recombination events between SLG, SRK, and self-incompatibility phenotype. In this paper, we use pulsed-field gel electrophoresis (PFGE) in conjunction with DNA blot analysis to characterize the S-locus region from two highly divergent self-incompatibility genotypes, S
2 and S
6. We establish the physical linkage of SLG and SRK in each genotype, and demonstrate that the two genes are separated by a maximum distance of 220 kb in the S
6 genotype and 350 kb in the S
2 genotype. Furthermore, a comparison of the data from the two genotypes reveals that a high level of polymorphism exists across the entire S-locus region. 相似文献
5.
Esch E 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2005,111(1):100-109
The gametes produced in meiosis provide information on the frequency of recombination and also on the interdependence of recombination events, i.e. interference. Using F2 individuals, it is not possible in all cases to derive the gametes, which have fused, and which provide the information about interference unequivocally when three or more segregating markers are considered simultaneously. Therefore, a method was developed to estimate the gametic frequencies using a maximum likelihood approach together with the expectation maximisation algorithm. This estimation procedure was applied to F2 mapping data from rice (Oryza sativa L.) to carry out a genome-wide analysis of crossover interference. The distribution of the coefficient of coincidence in dependence on the recombination fraction revealed for all chromosomes increasing positive interference with decreasing interval size. For some chromosomes this mutual inhibition of recombination was not so strong in small intervals. The centromere had a significant effect on interference. The positive interference found in the chromosome arms were reduced significantly when the intervals considered spanned the centromere. Two chromosomes even demonstrated independent recombination and slightly negative interference for small intervals including the centromere. Different marker densities had no effect on the results. In general, interference depended on the frequency of recombination events in relation to the physical length. The strength of the centromere effect on interference seemed to depend on the strength of recombination suppression around the centromere.Electronic Supplementary Material Supplementary material is available for this article at 相似文献
6.
Centromere mapping is a powerful tool for improving linkage maps, investigating crossover events, and understanding chiasma interference during meiosis. Ninety microsatellite markers selected across all linkage groups (LGs) from a previous Chlamys farreri genetic map were studied in three artificially induced meiogynogenetic families for centromere mapping by half-tetrad analysis. Inheritance analyses showed that all 90 microsatellite loci conformed to Mendelian inheritance in the control crosses, while 4.4 % of the microsatellite loci showed segregation departures from an expected 1:1 ratio of two homozygote classes in meiogynogenetic progeny. The second division segregation frequency (y) of the microsatellites ranged from 0.033 to 0.778 with a mean of 0.332, confirming the occurrence of partial chiasma interference in this species. Heterogeneity of y is observed in one of 42 cases in which markers were typed in more than one family, suggesting variation in gene–centromere recombination among families. Centromere location was mostly in accordance with the C. farreri karyotype, but differences in marker order between linkage and centromere maps occurred. Overall, this study makes the genetic linkage map a more complete and informative tool for genomic studies and it will also facilitate future research of the structure and function of the scallop centromeres. 相似文献
7.
C. Szpirer J. Szpirer F. Tissir E. Stephanova P. Vanvooren T. W. Kurtz N. Iwai T. Inagami M. Pravenec V. Kren K. Klinga-Levan G. Levan 《Mammalian genome》1997,8(9):657-660
Seven genes were regionally localized on rat Chromosome (Chr) 1, from 1p11 to 1q42, and two of these genes were also included
in a linkage map. This mapping work integrates the genetic linkage map and the cytogenetic map, and allows us to orient the
linkage map with respect to the centromere, and to deduce the approximate position of the centromere in the linkage map. These
mapping data also indicate that the Slc9a3 gene, encoding the Na+/H+ exchanger 3, is an unlikely candidate for the blood pressure loci assigned to rat Chr 1. These new localizations expand comparative
mapping between rat Chr 1 and mouse or human chromosomes.
Received: 21 March 1997 / Accepted: 3 May 1997 相似文献
8.
Morten T. Limborg Garrett J. McKinney Lisa W. Seeb James E. Seeb 《Molecular ecology resources》2016,16(3):655-661
Linkage mapping is often used to identify genes associated with phenotypic traits and for aiding genome assemblies. Still, many emerging maps do not locate centromeres – an essential component of the genomic landscape. Here, we demonstrate that for genomes with strong chiasma interference, approximate centromere placement is possible by phasing the same data used to generate linkage maps. Assuming one obligate crossover per chromosome arm, information about centromere location can be revealed by tracking the accumulated recombination frequency along linkage groups, similar to half‐tetrad analyses. We validate the method on a linkage map for sockeye salmon (Oncorhynchus nerka) with known centromeric regions. Further tests suggest that the method will work well in other salmonids and other eukaryotes. However, the method performed weakly when applied to a male linkage map (rainbow trout; O. mykiss) characterized by low and unevenly distributed recombination – a general feature of male meiosis in many species. Further, a high frequency of double crossovers along chromosome arms in barley reduced resolution for locating centromeric regions on most linkage groups. Despite these limitations, our method should work well for high‐density maps in species with strong recombination interference and will enrich many existing and future mapping resources. 相似文献
9.
Katarzyna Kulinska Tadeusz Kulinski Jacek Stawinski Aatto Laaksonen 《Journal of biomolecular structure & dynamics》2013,31(5):987-998
Abstract The hydration pattern of thymidyl(3′→5′) thymidine 1 and those of Rp and Sp diastereomers of the corresponding methylphosphonate analogue 2, have been studied using Molecular Dynamics (MD) computer simulation. It was found that the methylphosphonate modification leads to significant changes in the coordination of water molecules around the internucleotidic linkage and these, in turn, affect the hydration pattern of other parts of the molecule. The most notable differences between Rp and Sp diastereomers 2a and 2b were found to occur at the deoxyribose moieties of the nucleosid-5′-yl units. 相似文献
10.
The Genetics of a Probable Insertional Translocation in SORDARIA BREVICOLLIS 总被引:1,自引:1,他引:0
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Bond DJ 《Genetics》1979,92(1):75-82
A chromosome rearrangement has been isolated and characterized in Sordaria brevicollis. Crosses to spore color mutants on each of the seven linkage groups have enabled the breakpoints to be mapped. The simplest hypothesis to account for the results is that a piece of linkage group VI has been translocated to linkage group V and inserted 2.7 map units from its centromere. Previous reports of markers on this linkage group with centromere distances greater than 2.7 units make it unlikely that the translocation is quasiterminal. 相似文献
11.
Summary The interchromosomal effect of inversions in maize along the short arm of chromosome 9 yields results which are distinctly different from those which are reported with Drosophila melanogaster. Recombination was increased in the c
1-sh1 region of chromosome 9 while the sh
1-wx region was unaffected. This increased frequency of recombination appears to be due to an increase in single exchange events as multiple events were unchanged. Increases in recombination were accompanied by either an increase in chromosome interference or normal interference levels. The magnitude of increase in recombination was much smaller than that seen in interchromosomal effects in Drosophila and is consistent with other observations made in maize. When two inversions were present in the same nucleus simultaneously, the effect on recombination was of the same magnitude as the effect of a single inversion. All inversions tested, regardless of size or position with respect to the centromere showed the same magnitude of increase. 相似文献
12.
Anik K. Ratty Yoichi Matsuda Rosemary W. Elliott Verne M. Chapman Kenneth W. Gross 《Mammalian genome》1992,3(1):5-10
We present here the genetic mapping of two novel loci, D16Ros1 and D16Ros2, to mouse Chromosome (Chr) 16. The probes for these loci were genomic framents isolated from the chakragati mouse, a behavioural mutant resulting from insertional mutagenesis during the course of making transgenic mice. D16Ros1 and D16Ros2 were first mapped by recombinant inbred (RI) strain analysis and subsequently by the analysis of 145 progeny of two interspecific backcrosses between Mus domesticus and Mus spretus. These progeny had been typed for the centromere and this allowed mapping of D16Ros1 and D16Ros2 relative to the centromere. The other markers included in this study were Prm-1, Gap43 and Sod-1. The genetic map generated spanned 47.5 cM from the centromere to Sod-1, the most distal marker mapped here. The linkage data presented here should prove useful in mapping other loci relative to the centromere of Chr 16. 相似文献
13.
Jingxuan Zhu Xin Li Siqi Zhang Hen Ye Hui Zhao Hanyong Jin 《Journal of biomolecular structure & dynamics》2017,35(14):3140-3151
Wild-type phosphotriesterase (PTE) prefers the SP-enantiomers over the corresponding RP-enantiomers by factors ranging from 10 to 90. To satisfy the binding modes of the PTE of SP- and RP-enantiomers, all-atom molecular dynamics simulations were carried out on two paraoxon SP and RP derivatives, namely, Sp-1 and Rp-1. Molecular mechanics Poisson–Boltzmann surface area and molecular mechanics generalized Born surface area (MM-PBSA and MM-GBSA) calculations indicated that His230 in Sp-1-PTE had a closer interaction with the substrate than that in Rp-1-PTE and that such interaction increased the catalytic efficiency of PTE for Sp-1. The steered molecular dynamics simulation indicated that, compared with Sp-1, Rp-1 in the unbinding (binding) may hinder some residue displacement, thus requiring more effort to escape the binding pocket of PTE. In addition, Trp131, Phe306, and Tyr309 are deemed important residues for the Sp-1 unbinding pathway via PTE, whereas Tyr309 alone is considered an important residue for the Rp-1 unbinding pathway. These results demonstrate the possibility of dramatically altering the stereoselectivity and overall reactivity of the native enzyme toward chiral substrates by modifying specific residues located within the active site of PTE. 相似文献
14.
Md. Habibur Rahman Tohru Tsuchiya Keita Suwabe Junna Kohori Rubens Norio Tomita Yasuaki Kagaya Issei Kobayashi Katsuyuki Kakeda Yasuo Kowyama 《Sexual plant reproduction》2007,20(2):63-72
Sporophytic self-incompatibility (SSI) in the genus Ipomoea (Convolvulaceae) is controlled by a single polymorphic S locus. We have previously analyzed genomic sequences of an approximately 300 kb region spanning the S locus of the S
1
haplotype and characterized the genomic structure around this locus. Here, we further define the physical size of the S locus region by mapping recombination breakpoints, based on sequence analysis of PCR fragments amplified from the genomic
DNA of recombinants. From the recombination analysis, the S locus of the S
1
haplotype was delimited to a 0.23 cM region of the linkage map, which corresponds to a maximum physical size of 212 kb. To
analyze differences in genomic organization between S haplotypes, fosmid contigs spanning approximately 67 kb of the S
10
haplotype were sequenced. Comparison with the S
1
genomic sequence revealed that the S haplotype-specific divergent regions (SDRs) spanned 50.7 and 34.5 kb in the S
1
and S
10
haplotypes, respectively and that their flanking regions showed a high sequence similarity. In the sequenced region of the
S
10
haplotype, five of the 12 predicted open reading frames (ORFs) were found to be located in the divergent region and showed
co-linear organization of genes between the two S haplotypes. Based on the size of the SDRs, the physical size of the S locus was estimated to fall within the range 34–50 kb in Ipomoea. 相似文献
15.
Summary Tetrad and random spore analyses have been used to further develop the genetic map of Saccharomycopsis lipolytica. Mutations in 23 new nuclear genes have been isolated. Eight genes have been located on linkage fragment 1, 4 on fragment 2, 2 on fragment 5 and 3 on fragment 6. Linkage fragments 3 and 4 have been shown to be linked, and this fragment now contains 12 markers. A tentative map of the linkage fragments 1 and 3 is presented (Fig. 1). Markers exhibiting possible centromere linkage have been identified. Interference estimates suggest that there is little interference in S. lipolytica. 相似文献
16.
Marshall K. Tulloch‐Reid Robert L. Hanson Nancy G. Sebring James C. Reynolds Ahalya Premkumar David J. Genovese Anne E. Sumner 《Obesity (Silver Spring, Md.)》2004,12(8):1352-1359
Objective: The contribution of visceral adipose tissue (VAT) to insulin resistance is well‐established; however, the role of subcutaneous abdominal adipose tissue (SAT) in insulin resistance remains controversial. Sex may determine which of these two components of abdominal obesity is more strongly related to insulin resistance and its consequences. The aim of this study was to determine whether both VAT and SAT contribute to insulin resistance in African Americans and to examine the effects of sex on this relationship. Research Methods and Procedures: This was a cross‐sectional study of 78 nondiabetic African‐American volunteers (44 men, 35 women; age 33.8 ± 7.3 years; BMI 30.9 ± 7.4 kg/m2). VAT and SAT volumes were measured using serial computerized tomography slices from the dome of the diaphragm to the iliac crest. The insulin sensitivity index (SI) was determined from the minimal model using data obtained from the frequently sampled intravenous glucose tolerance test. Results: In men, both VAT and SAT were negatively correlated with SI (r for both correlations = ?0.57; p < 0.01). In women, the correlation coefficient between VAT and SI was ?0.50 (p < 0.01) and between SAT and SI was ?0.67 (p < 0.01). In women, the correlation coefficient for SI with SAT was significantly greater than the correlation coefficient with VAT (p = 0.02). Discussion: Both SAT and VAT are strongly correlated with insulin resistance in African Americans. For African‐American women, SAT may have a greater effect than VAT on insulin resistance. 相似文献
17.
D. D. Shaw 《Chromosoma》1970,30(3):326-343
Three species of the genus Stethophyma carry supernumerary heterochromatic segments. The European species, S. grossa, has segments located close to the centromere on the S11 chromosome pair, while the North American species, S. lineatum and S. gracile, have both interstitial and terminal segments on the S10 and S11 chromosomes. The latter species show a high degree of segment variation between individuals and the interstitial segments also show variation in size. The presence of segments on the S10 and S11 chromosomes, whether homozygous or heterozygous, modifies the pattern of chiasma distribution in these chromosomes when compared with that found in the basic homozygotes. When interstitial, they also lead to a high frequency of ring bivalents.Two points suggest that interstitially located supernumerary segments may prove to be more common than has previously been accepted. Firstly, combined equational and reductional segregation in unequal bivalents is only otherwise explicable in terms of chiasma formation in a short arm. Secondly the rod chromosomes of many Acridids may well be telocentric as in the case under study.It is proposed that these segments have arisen through a process of duplication with no evidence of interchromosomal movement.On educational leave from the Forest Research Laboratory, Canadian Forestry Service, Fredericton, New Brunswick, Canada. 相似文献
18.
D. Childress 《Molecular & general genetics : MGG》1973,121(2):133-138
Summary Females homozygous and heterozygous for the B
S translocation were tested to determine the extent of the intra- and interchromosomal effects caused by the rearrangement. The heterozygous translocation produces an increase in crossing over at the tip of the X and in the centromere region of chromosome 2. The homozygous translocation has no effect on crossing over in these regions, but an unexpected increase is observed near the centromere region of the B
S segment. This result is not predicted by the time-delay model for interchromsomal effects.Supported by USPHS Training Grant 5T1 GM 1145-05 and NSF GB 18786. 相似文献
19.
Genetic linkage map of ISSR and RAPD markers in Einkorn wheat in relation to that of RFLP markers 总被引:41,自引:0,他引:41
T. Kojima T. Nagaoka K. Noda Y. Ogihara 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1998,96(1):37-45
The potential of PCR-based markers for construction of a genetic linkage map in Einkorn wheat was investigated. From a comparison
of polymorphisms between two Einkorn wheats, Triticum monococcum (Mn) and T. boeoticum (Bt), we obtained 49 polymorphic bands produced by 33 primers for inter-simple sequence repeat (ISSR) and 36 polymorphic
bands shown by 25 combinations of random amplified polymorphic DNA (RAPD) primers for mapping in 66 individuals in the F2 population. Although 44 ISSR fragments and 29 RAPD fragments statistically showed a 3 : 1 segregation ratio in the F2 population, only 9 markers each of the ISSR and RAPD bands were able to be mapped on the RFLP linkage map of Einkorn wheat.
ISSR markers were distributed throughout the chromosomes. The mapped positions of the ISSR markers seemed to be similar to
those obtained by the RFLP markers. On the other hand, 4 of the 9 RAPD markers could map the RFLP marker-poor region on the
short arm of 3Am, suggesting a potential to map novel regions containing repetitive sequences. Comparisons of the genetic linkage map of Einkorn
wheat to the linkage map and cytological map of common wheat revealed that the marker orders between the two maps of Einkorn
wheat and common wheat coincided except for 4A, which harbors chromosome rearrangements specific for polyploid wheats, indicating
a conservatism between the two genomes. Recombinations in Einkorn wheat chromosomes took place more frequently around the
centromere and less at the distal part of chromosomes in comparison to those in common wheat. Nevertheless, recombinations
even in Einkorn wheat chromosomes were strongly suppressed around the centromere. In fact, the markers located within 1 cM
of the centromere were located almost in the central part of the chromosome arm.
Received: 7 June 1997 / Accepted: 17 June 1997 相似文献
20.
Serge Alonso Xavier Montagutelli Dominique Simon-Chazottes Jean-Louis Guénet Margaret Buckingham 《Mammalian genome》1993,4(1):15-20
We present here the genetic mapping of the -skeletal actin locus (Actsk-1) on mouse Chromosome (Chr) 8, on the basis of the PCR analysis of a microsatellite in an interspecific backcross. Linkage and genetic distances were established for four loci by analysis of 192 (or 222) meiotic events and indicated the following gene order: (centromere)-Es-1-11.7 cM-Tat-8.3 cM-Actsk-1-0.5 cM-Aprt. Mapping of ACTSK to human Chr 1 and of TAT and APRT to human Chr 16 demonstrates the existence of a new short region of homology between mouse Chr 8 and human Chr 1. Intermingling on this scale between human and mouse chromosomal homologies that occurred during evolution creates disorders in comparative linkage studies. 相似文献