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1.
Zsuzsanna Schwarz-Sommer Thomas Gübitz Julia Weiss Perla Gómez-di-Marco Luciana Delgado-Benarroch Andrew Hudson Marcos Egea-Cortines 《BMC plant biology》2010,10(1):275
Background
Genetic recombination maps provide important frameworks for comparative genomics, identifying gene functions, assembling genome sequences and for breeding. The molecular recombination map currently available for the model eudicot Antirrhinum majus is the result of a cross with Antirrhinum molle, limiting its usefulness within A. majus. 相似文献2.
Background
Vibrio cholerae gains natural competence upon growth on chitin. This allows the organism to take up free DNA from the environment and to incorporate it into its genome by homologous recombination. 相似文献3.
Nicolas Corradi Karen L Haag Jean-François Pombert Dieter Ebert Patrick J Keeling 《Genome biology》2009,10(10):R106-12
Background
The highly compacted 2.9-Mb genome of Encephalitozoon cuniculi placed the microsporidia in the spotlight, encoding a mere 2,000 proteins and a highly reduced suite of biochemical pathways. This extreme level of reduction is not universal across the microsporidia, with genomes known to vary up to sixfold in size, suggesting that some genomes may harbor a gene content that is not as reduced as that of Enc. cuniculi. In this study, we present an in-depth survey of the large genome of Octosporea bayeri, a pathogen of Daphnia magna, with an estimated genome size of 24 Mb, in order to shed light on the organization and content of a large microsporidian genome. 相似文献4.
Ruth?Tachezy Annabel?Rector Marta?Havelkova Elke?Wollants Pierre?Fiten Ghislain?Opdenakker A?Bennett?Jenson John?P?Sundberg Marc?Van Ranst
Background
An avian papillomavirus genome has been cloned from a cutaneous exophytic papilloma from an African grey parrot (Psittacus erithacus). The nucleotide sequence, genome organization, and phylogenetic position of the Psittacus erithacus papillomavirus (PePV) were determined. This PePV sequence represents the first complete avian papillomavirus genome defined. 相似文献5.
Background
Analysis of the first reported complete genome sequence ofBifidobacterium longumNCC2705, an actinobacterium colonizing the gastrointestinal tract, uncovered its proteomic relatedness toStreptomyces coelicolorandMycobacterium tuberculosis. However, a rapid scrutiny by genometric methods revealed a genome organization totally different from all so far sequenced high-GC Gram-positive chromosomes. 相似文献6.
Background
Whole genome duplication is a common evolutionary event in plants. Bread wheat (Triticum aestivum L.) is a good model to investigate the impact of paleo- and neoduplications on the organization and function of modern plant genomes. 相似文献7.
Background
Cre-mediated site-specific integrative recombination in mouse embryonic stem (ES) cells is a useful tool for genome engineering, allowing precise and repeated site-specific integration. To promote the integrative reaction, a left element/right element (LE/RE) mutant strategy using a pair of lox sites with mutations in the LE or RE of the lox sequence has previously been developed. Recombination between LE and RE mutant lox produces a wild-type lox P site as well as an LE+RE double mutant lox site, which has mutations in both sides and less affinity to Cre, resulting in stable integration. We previously demonstrated successful integrative recombination using lox 71 (an LE mutant) and lox 66 (an RE mutant) in ES cells. Recently, other LE/RE mutant lox sites showing higher recombination efficiency in Escherichia coli have been reported. However, their recombination efficiency in mammalian cells remains to be analyzed. 相似文献8.
9.
10.
Origins of chromosomal rearrangement hotspots in the human genome: evidence from the <Emphasis Type="Italic">AZFa</Emphasis>deletion hotspots 总被引:1,自引:1,他引:0
Background
The origins of the recombination hotspots that are a common feature of both allelic and non-allelic homologous recombination in the human genome are poorly understood. We have investigated, by comparative sequencing, the evolution of two hotspots of non-allelic homologous recombination on the Y chromosome that lie within paralogous sequences known to sponsor deletions resulting in male infertility. 相似文献11.
GC- and AT-rich chromatin domains differ in conformation and histone modification status and are differentially modulated by Rpd3p 总被引:1,自引:0,他引:1
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Dekker J 《Genome biology》2007,8(6):R116
Background
Base-composition varies throughout the genome and is related to organization of chromosomes in distinct domains (isochores). Isochore domains differ in gene expression levels, replication timing, levels of meiotic recombination and chromatin structure. The molecular basis for these differences is poorly understood. 相似文献12.
Marco Fondi Giovanni Bacci Matteo Brilli Maria Cristiana Papaleo Alessio Mengoni Mario Vaneechoutte Lenie Dijkshoorn Renato Fani 《BMC evolutionary biology》2010,10(1):59
Background
Prokaryotic plasmids have a dual importance in the microbial world: first they have a great impact on the metabolic functions of the host cell, providing additional traits that can be accumulated in the cell without altering the gene content of the bacterial chromosome. Additionally and/or alternatively, from a genome perspective, plasmids can provide a basis for genomic rearrangements via homologous recombination and so they can facilitate the loss or acquisition of genes during these events, which eventually may lead to horizontal gene transfer (HGT). Given their importance for conferring adaptive traits to the host organisms, the interest in plasmid sequencing is growing and now many complete plasmid sequences are available online. 相似文献13.
Wei Zhang Xianwen Zhu Mingyi Zhang Shiaoman Chao Steven Xu Xiwen Cai 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2018,131(11):2381-2395
Key message
We physically dissected and mapped wheat chromosome 2B and its homoeologues in Aegilops speltoides and Thinopyrum elongatum based on meiotic homoeologous recombination, providing a unique physical framework for genome studies.Abstract
Common wheat has a large and complex genome with narrow genetic diversity and various degrees of recombination between the A, B, and D subgenomes. This has limited the homologous recombination-based genome studies in wheat. Here, we exploited meiotic homoeologous recombination for molecular mapping of wheat chromosome 2B and its homoeologue 2S from Aegilops speltoides and 2E from Thinopyrum elongatum. The 2B–2S and 2B–2E recombination was induced by the ph1b mutant, and recovered using molecular markers and fluorescent genomic in situ hybridization (FGISH). A total of 112 2B–2S and 87 2B–2E recombinants involving different chromosome regions were developed and physically delineated by FGISH. The 2B–2S and 2B–2E recombination hotspots mapped to the subterminal regions on both arms. Recombination hotspots with the highest recombination rates mapped to the short arms. Eighty-three 2B–2S and 67 2B–2E recombinants were genotyped using the wheat 90 K SNP arrays. Based on the genotyping results and FGISH patterns of the recombinants, chromosomes 2B, 2S, and 2E were partitioned into 93, 66, and 46 bins, respectively. In total, 1037 SNPs physically mapped onto distinct bins of these three homoeologous chromosomes. A homoeologous recombination-based bin map was constructed for chromosome 2B, providing a unique physical framework for genome studies in wheat and its relatives. Meiotic homoeologous recombination also facilitates gene introgression to diversify the wheat genome for germplasm development. Therefore, homoeologous recombination-based studies enhance understanding of the wheat genome and its homoeologous counterparts from wild grasses, and expand the genetic variability of the wheat genome.14.
Hanan Sela Caroline Loutre Beat Keller Alan Schulman Eviatar Nevo Abraham Korol Tzion Fahima 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2011,122(1):175-187
Introduction
Recombination is a key evolutionary factor enhancing diversity. However, the effect of recombination on diversity in inbreeding species is expected to be low. To estimate this effect, recombination and diversity patterns of Lr10 gene were studied in natural populations of the inbreeder species, wild emmer wheat (Triticum dicoccoides). Wild emmer wheat is the progenitor of most cultivated wheats and it harbors rich genetic resources for disease resistance. Lr10 is a leaf rust resistance gene encoding three domains: a coiled-coil, nucleotide-binding site, and leucine-rich repeat (CC-NBS-LRR). 相似文献15.
Caitlin R Ross Dominick S DeFelice Greg J Hunt Kate E Ihle Gro V Amdam Olav Rueppell 《BMC genomics》2015,16(1)
Background
Meiotic recombination has traditionally been explained based on the structural requirement to stabilize homologous chromosome pairs to ensure their proper meiotic segregation. Competing hypotheses seek to explain the emerging findings of significant heterogeneity in recombination rates within and between genomes, but intraspecific comparisons of genome-wide recombination patterns are rare. The honey bee (Apis mellifera) exhibits the highest rate of genomic recombination among multicellular animals with about five cross-over events per chromatid.Results
Here, we present a comparative analysis of recombination rates across eight genetic linkage maps of the honey bee genome to investigate which genomic sequence features are correlated with recombination rate and with its variation across the eight data sets, ranging in average marker spacing ranging from 1 Mbp to 120 kbp. Overall, we found that GC content explained best the variation in local recombination rate along chromosomes at the analyzed 100 kbp scale. In contrast, variation among the different maps was correlated to the abundance of microsatellites and several specific tri- and tetra-nucleotides.Conclusions
The combined evidence from eight medium-scale recombination maps of the honey bee genome suggests that recombination rate variation in this highly recombining genome might be due to the DNA configuration instead of distinct sequence motifs. However, more fine-scale analyses are needed. The empirical basis of eight differing genetic maps allowed for robust conclusions about the correlates of the local recombination rates and enabled the study of the relation between DNA features and variability in local recombination rates, which is particularly relevant in the honey bee genome with its exceptionally high recombination rate.Electronic supplementary material
The online version of this article (doi:10.1186/s12864-015-1281-2) contains supplementary material, which is available to authorized users. 相似文献16.
Background
The molecular organization of very few genetically defined CACTA transposon systems have been characterized thoroughly as those of Spm/En in maize, Tam1 of Antirrhinum majus Candystripe1 (Cs1) from Sorghum bicolor and CAC1 from Arabidopsis thaliana, for example. To date, only defective deletion derivatives of CACTA elements have been described for soybean, an economically important plant species whose genome sequence will be completed in 2008. 相似文献17.
Background
Enzymes involved in DNA metabolic events of the highly radioresistant bacterium Deinococcus radiodurans are currently examined to understand the mechanisms that protect and repair the Deinococcus radiodurans genome after extremely high doses of γ-irradiation. Although several Deinococcus radiodurans DNA repair enzymes have been characterised, no biochemical data is available for DNA ligation and DNA endhealing enzymes of Deinococcus radiodurans so far. DNA ligases are necessary to seal broken DNA backbones during replication, repair and recombination. In addition, ionizing radiation frequently leaves DNA strand-breaks that are not feasible for ligation and thus require end-healing by a 5'-polynucleotide kinase or a 3'-phosphatase. We expect that DNA ligases and end-processing enzymes play an important role in Deinococcus radiodurans DNA strand-break repair. 相似文献18.
Lara-Ramírez EE Segura-Cabrera A Guo X Yu G García-Pérez CA Rodríguez-Pérez MA 《PloS one》2011,6(2):e17300
Background
Helicobacter pylori has a reduced genome and lives in a tough environment for long-term persistence. It evolved with its particular characteristics for biological adaptation. Because several H. pylori genome sequences are available, comparative analysis could help to better understand genomic adaptation of this particular bacterium.Principal Findings
We analyzed nine H. pylori genomes with emphasis on microevolution from a different perspective. Inversion was an important factor to shape the genome structure. Illegitimate recombination not only led to genomic inversion but also inverted fragment duplication, both of which contributed to the creation of new genes and gene family, and further, homological recombination contributed to events of inversion. Based on the information of genomic rearrangement, the first genome scaffold structure of H. pylori last common ancestor was produced. The core genome consists of 1186 genes, of which 22 genes could particularly adapt to human stomach niche. H. pylori contains high proportion of pseudogenes whose genesis was principally caused by homopolynucleotide (HPN) mutations. Such mutations are reversible and facilitate the control of gene expression through the change of DNA structure. The reversible mutations and a quasi-panmictic feature could allow such genes or gene fragments frequently transferred within or between populations. Hence, pseudogenes could be a reservoir of adaptation materials and the HPN mutations could be favorable to H. pylori adaptation, leading to HPN accumulation on the genomes, which corresponds to a special feature of Helicobacter species: extremely high HPN composition of genome.Conclusion
Our research demonstrated that both genome content and structure of H. pylori have been highly adapted to its particular life style. 相似文献19.
Recombination plays an important role in species adaptation since it acts as an evolutionary force that can influence genome
pattern organization. However, recombination can be detrimental in some situations, causing the breakdown of some adaptive
gene combinations such as coadapted gene complexes. Genetic and cytological chromosome maps allow recombination throughout
the genome to be analyzed. In this study we compare the recombination rate of two types of homokaryotypic lines of D. subobscura (OST and O
3+4
) using a set of at least 13 microsatellite loci. The genetic maps obtained present similar lengths: 184 and 196 cM for OST and O
3+4
chromosomes, respectively. For most pairs of markers analyzed, a sample size of about 150 individuals appeared sufficient
to obtain appropriate recombination values, with the exception of markers located in the same cytological band. Recombination
rates seemed to be fairly uniform along the O chromosome, but some regional differences were observed. Several recombination
hot and coldspots were detected, and their numbers were different in the homokaryotypic line types (OST and O
3+4
). This variability could be attributed to differences between the genetic content of the two arrangements or to differences
between the lines. 相似文献
20.
Helena T Funk Sabine Berg Karin Krupinska Uwe G Maier Kirsten Krause 《BMC plant biology》2007,7(1):45