scholarly journals DECONVOLUTING BAC–GENE RELATIONSHIPS USING A PHYSICAL MAP

2008 ◽  
Vol 06 (03) ◽  
pp. 603-622
Author(s):  
YONGHUI WU ◽  
LAN LIU ◽  
TIMOTHY J. CLOSE ◽  
STEFANO LONARDI
Keyword(s):  
Physical Map ◽  
Bac Library ◽  
Artificial Chromosome ◽  
Hybridization Experiment ◽  
Pooling Design ◽  
Bac Clones ◽  
Hybridization Data ◽  
A Genome ◽  
The Right ◽  
Combinatorial Pooling

Deconvolution of relationships between bacterial artificial chromosome (BAC) clones and genes is a crucial step in the selective sequencing of regions of interest in a genome. It often includes combinatorial pooling of unique probes obtained from the genes (unigenes), and screening of the BAC library using the pools in a hybridization experiment. Since several probes can hybridize to the same BAC, in order for the deconvolution to be achievable the pooling design has to be able to handle a large number of positives. As a consequence, smaller pools need to be designed, which in turn increases the number of hybridization experiments, possibly making the entire protocol unfeasible. We propose a new algorithm that is capable of producing high-accuracy deconvolution even in the presence of a weak pooling design, i.e. when pools are rather large. The algorithm compensates for the decrease of information in the hybridization data by taking advantage of a physical map of the BAC clones. We show that the right combination of combinatorial pooling and our algorithm not only dramatically reduces the number of pools required, but also successfully deconvolutes the BAC–gene relationships with almost perfect accuracy. Software is available on request from the first author.

scholarly journals Development of a sequence-based reference physical map of pea (Pisum sativum L.)

2019 ◽  
Author(s):  
Krishna Kishore Gali ◽  
Bunyamin Tar’an ◽  
Mohammed-Amin Madoui ◽  
Edwin van der Vossen ◽  
Jan van Oeveren ◽  
...  
Keyword(s):  
Genome Sequence ◽  
Positional Cloning ◽  
Physical Map ◽  
Repetitive Sequences ◽  
Bac Library ◽  
Artificial Chromosome ◽  
Bac Clones ◽  
Pooled Dna ◽  
Mapping Technology ◽  
Generation Sequencing

AbstractWhole genome profiling (WGP) is a sequence-based physical mapping technology and uses sequence tags generated by next generation sequencing for construction of bacterial artificial chromosome (BAC) contigs of complex genomes. The physical map provides a framework for assembly of genome sequence and information for localization of genes that are difficult to find through positional cloning. To address the challenges of accurate assembly of the pea genome (~4.2 GB of which approximately 85% is repetitive sequences), we have adopted the WGP technology for assembly of a pea BAC library. Multi-dimensional pooling of 295,680 BAC clones and sequencing the ends of restriction fragments of pooled DNA generated 1,814 million high quality reads, of which 825 million were deconvolutable to 1.11 million unique WGP sequence tags. These WGP tags were used to assemble 220,013 BACs into contigs. Assembly of the BAC clones using the modified Fingerprinted Contigs (FPC) program has resulted in 13,040 contigs, consisting of 213,719 BACs, and 6,294 singleton BACs. The average contig size is 0.33 Mbp and the N50 contig size is 0.62 Mbp. WGPTM technology has proved to provide a robust physical map of the pea genome, which would have been difficult to assemble using traditional restriction digestion based methods. This sequence-based physical map will be useful to assemble the genome sequence of pea. Additionally, the 1.1 million WGP tags will support efficient assignment of sequence scaffolds to the BAC clones, and thus an efficient sequencing of BAC pools with targeted genome regions of interest.

Construction of a bacterial artificial chromosome (BAC) library for potato molecular cytogenetics research

Genome ◽  
2000 ◽  
Vol 43 (1) ◽  
pp. 199-204 ◽  
Author(s):  
Junqi Song ◽  
Fenggao Dong ◽  
Jiming Jiang
Keyword(s):  
Bacterial Artificial Chromosome ◽  
Physical Map ◽  
Molecular Cytogenetics ◽  
Bac Library ◽  
Artificial Chromosome ◽  
Average Insert Size ◽  
Chromosome Identification ◽  
Insert Size ◽  
Potato Genome ◽  
Bac Clones

Lack of reliable techniques for chromosome identification is the major obstacle for cytogenetics research in plant species with large numbers of small chromosomes. To promote molecular cytogenetics research of potato (Solanum tuberosum, 2n = 4x = 48) we developed a bacterial artificial chromosome (BAC) library of a diploid potato species S. bulbocastanum. The library consists of 23 808 clones with an average insert size of 155 kb, and represents approximately 3.7 equivalents to the potato genome. The majority of the clones in the BAC library generated distinct signals on specific potato chromosomes using fluorescence in situ hybridization (FISH). The hybridization signals provide excellent cytological markers to tag individual potato chromosomes. We also demonstrated that the BAC clones can be mapped to specific positions on meiotic pachytene chromosomes. The excellent resolution of pachytene FISH can be used to construct a physical map of potato by mapping molecular marker-targeted BAC clones on pachytene chromosomes. Key words: potato, BAC library, chromosome identification, physical mapping, molecular cytogenetics.

scholarly journals Construction and Characterization of a Bacterial Artificial Chromosome Library for the A-Genome of Cotton (G.arboreumL.)

2011 ◽  
Vol 2011 ◽  
pp. 1-5 ◽  
Author(s):  
Yan Hu ◽  
Yamin Lu ◽  
Dan Ma ◽  
Wangzhen Guo ◽  
Tianzhen Zhang
Keyword(s):  
Bacterial Artificial Chromosome ◽  
Bac Library ◽  
Artificial Chromosome ◽  
Gene Isolation ◽  
Comparative Genome Analysis ◽  
Bac Clones ◽  
A Genome ◽  
Reference Map ◽  
Insert Length

A bacterial artificial chromosome (BAC) library for the A-genome of cotton has been constructed from the leaves ofG. arboreumL cv. Jianglinzhongmian. It is used as elite A-genome germplasm resources in the present cotton breeding program and has been used to build a genetic reference map of cotton. The BAC library consists of 123,648 clones stored in 322 384-well plates. Statistical analysis of a set of 103 randomly selected BAC clones indicated that each clone has an average insert length of 100.2 kb per plasmid, with a range of 30 to 190 kb. Theoretically, this represents 7.2 haploid genome equivalents based on an A-genome size of 1697 Mb. The BAC library has been arranged in column pools and superpools allowing screening with various PCR-based markers. In the future, the A-genome cotton BAC library will serve as both a giant gene resource and a valuable tool for map-based gene isolation, physical mapping and comparative genome analysis.

Construction and characterization of bacterial artificial chromosome library of black-handed spider monkey (Ateles geoffroyi)

Genome ◽  
2004 ◽  
Vol 47 (2) ◽  
pp. 239-245 ◽  
Author(s):  
Yaping Qian ◽  
Li Jin ◽  
Bing Su
Keyword(s):  
Bacterial Artificial Chromosome ◽  
Large Scale ◽  
Bac Library ◽  
Artificial Chromosome ◽  
Spider Monkey ◽  
Ateles Geoffroyi ◽  
Comparative Genomic ◽  
Average Insert Size ◽  
Bac Clones ◽  
Genomic Study

The large-insert genomic DNA library is a critical resource for genome-wide genetic dissection of target species. We constructed a high-redundancy bacterial artificial chromosome (BAC) library of a New World monkey species, the black-handed spider monkey (Ateles geoffroyi). A total of 193 152 BAC clones were generated in this library. The average insert size of the BAC clones was estimated to be 184.6 kb with the small inserts (50-100 kb) accounting for less than 3% and the non-recombinant clones only 1.2%. Assuming a similar genome size with humans, the spider monkey BAC library has about 11× genome coverage. In addition, by end sequencing of randomly selected BAC clones, we generated 367 sequence tags for the library. When blasted against human genome, they showed a good correlation between the number of hit clones and the size of the chromosomes, an indication of unbiased chromosomal distribution of the library. This black-handed spider monkey BAC library would serve as a valuable resource in comparative genomic study and large-scale genome sequencing of nonhuman primates.Key words: black-handed spider monkeys, Ateles geoffroyi, BAC library.

scholarly journals Use of a Mycobacterium tuberculosisH37Rv Bacterial Artificial Chromosome Library for Genome Mapping, Sequencing, and Comparative Genomics

1998 ◽  
Vol 66 (5) ◽  
pp. 2221-2229 ◽  
Author(s):  
Roland Brosch ◽  
Stephen V. Gordon ◽  
Alain Billault ◽  
Thierry Garnier ◽  
Karin Eiglmeier ◽  
...  
Keyword(s):  
Comparative Genomics ◽  
Bacterial Artificial Chromosome ◽  
Genome Mapping ◽  
Sequence Data ◽  
Bac Library ◽  
Artificial Chromosome ◽  
Excellent Correlation ◽  
Sequencing Project ◽  
Polysaccharide Biosynthesis ◽  
Bac Clones

ABSTRACT The bacterial artificial chromosome (BAC) cloning system is capable of stably propagating large, complex DNA inserts in Escherichia coli. As part of the Mycobacterium tuberculosis H37Rv genome sequencing project, a BAC library was constructed in the pBeloBAC11 vector and used for genome mapping, confirmation of sequence assembly, and sequencing. The library contains about 5,000 BAC clones, with inserts ranging in size from 25 to 104 kb, representing theoretically a 70-fold coverage of the M. tuberculosisgenome (4.4 Mb). A total of 840 sequences from the T7 and SP6 termini of 420 BACs were determined and compared to those of a partial genomic database. These sequences showed excellent correlation between the estimated sizes and positions of the BAC clones and the sizes and positions of previously sequenced cosmids and the resulting contigs. Many BAC clones represent linking clones between sequenced cosmids, allowing full coverage of the H37Rv chromosome, and they are now being shotgun sequenced in the framework of the H37Rv sequencing project. Also, no chimeric, deleted, or rearranged BAC clones were detected, which was of major importance for the correct mapping and assembly of the H37Rv sequence. The minimal overlapping set contains 68 unique BAC clones and spans the whole H37Rv chromosome with the exception of a single gap of ∼150 kb. As a postgenomic application, the canonical BAC set was used in a comparative study to reveal chromosomal polymorphisms between M. tuberculosis, M. bovis, and M. bovis BCG Pasteur, and a novel 12.7-kb segment present in M. tuberculosis but absent from M. bovis and M. bovis BCG was characterized. This region contains a set of genes whose products show low similarity to proteins involved in polysaccharide biosynthesis. The H37Rv BAC library therefore provides us with a powerful tool both for the generation and confirmation of sequence data as well as for comparative genomics and other postgenomic applications. It represents a major resource for present and future M. tuberculosis research projects.

Construction of a hexaploid wheat (Triticum aestivumL.) bacterial artificial chromosome library for cloning genes for stripe rust resistance

Genome ◽  
2005 ◽  
Vol 48 (6) ◽  
pp. 1028-1036 ◽  
Author(s):  
P Ling ◽  
X M Chen
Keyword(s):  
Triticum Aestivum ◽  
Stripe Rust ◽  
Hexaploid Wheat ◽  
Rust Resistance ◽  
Puccinia Striiformis ◽  
Bac Library ◽  
Artificial Chromosome ◽  
Stripe Rust Resistance ◽  
Insert Size ◽  
Bac Clones

A hexaploid wheat (Triticum aestivum L.) bacterial artificial chromosome (BAC) library was constructed for cloning Yr5 and other genes conferring resistance to stripe rust (Puccinia striiformis f. sp. tritici). Intact nuclei from a Yr5 near-isogenic line were used to isolate high molecular weight DNA, which was partially cleaved with HindIII and cloned into pECBAC1 and pIndigoBAC-5 vectors. The wheat BAC library consisted of 422 400 clones arrayed in 1100 micro-titer plates (each plate with 384 wells). Random sampling of 300 BAC clones indicated an average insert size of 140 kb, with a size range from 25 to 365 kb. Ninety percent of the clones in the library had an insert size greater than 100 kb and fewer than 5% of the clones did not contain inserts. Based on an estimated genome size of 15 966 Mb for hexaploid wheat, the BAC library was estimated to have a total coverage of 3.58× wheat genome equivalents, giving approximately 96% probability of identifying a clone representing any given wheat DNA sequence. Twelve BAC clones containing an Yr5 locus-specific marker (Yr5STS7/8) were successfully selected by PCR screening of 3-dimensional BAC pools. The results demonstrated that the T. aestivum BAC library is a valuable genomic resource for positional cloning of Yr5. The library also should be useful in cloning other genes for stripe rust resistance and other traits of interest in hexaploid wheat.Key words: BAC library, BAC pools, hexaploid wheat, Puccinia striiformis f. sp. tritici, resistance gene, stripe rust, Triticum aestivum.

Comparison of the chromosome maps around a resistance hot spot on chromosome 5 of potato and tomato using BAC-FISH painting

Genome ◽  
2010 ◽  
Vol 53 (2) ◽  
pp. 103-110 ◽  
Author(s):  
Ute C. Achenbach ◽  
Xiaomin Tang ◽  
Agim Ballvora ◽  
Hans de Jong ◽  
Christiane Gebhardt
Keyword(s):  
Hot Spot ◽  
Artificial Chromosome ◽  
Globodera Pallida ◽  
Chromosome 5 ◽  
Physical Size ◽  
Bac Clones ◽  
A Genome ◽  
Chromosome Maps ◽  
Bac Fish

Potato chromosome 5 harbours numerous genes for important qualitative and quantitative traits, such as resistance to the root cyst nematode Globodera pallida and the late blight fungus, Phytophthora infestans . The genes make up part of a “hot spot” for resistances to various pathogens covering a genetic map length of 3 cM between markers GP21 and GP179. We established the physical size and position of this region on chromosome 5 in potato and tomato using fluorescence in situ hybridization (FISH) on pachytene chromosomes. Five potato bacterial artificial chromosome (BAC) clones with the genetically anchored markers GP21, R1-contig (proximal end), CosA, GP179, and StPto were selected, labeled with different fluorophores, and hybridized in a five-colour FISH experiment. Our results showed the location of the BAC clones in the middle of the long arm of chromosome 5 in both potato and tomato. Based on chromosome measurements, we estimate the physical size of the GP21–GP179 interval at 0.85 Mb and 1.2 Mb in potato and tomato, respectively. The GP21–GP179 interval is part of a genome segment known to have inverted map positions between potato and tomato.

scholarly journals A Bacterial Artificial Chromosome Contig Spanning the Major Domestication Locus Q in Wheat and Identification of a Candidate Gene

Genetics ◽  
2003 ◽  
Vol 164 (1) ◽  
pp. 311-321 ◽  
Author(s):  
Justin D Faris ◽  
John P Fellers ◽  
Steven A Brooks ◽  
Bikram S Gill
Keyword(s):  
Physical Map ◽  
Bac Library ◽  
Wheat Chromosome ◽  
Artificial Chromosome ◽  
Physical Distance ◽  
Bac Contig ◽  
Complete Sequencing ◽  
Bacterial Artificial Chromosome Contig ◽  
Q Gene ◽  
Similarity Searches

Abstract The Q locus played a major role in the domestication of wheat because it confers the free-threshing character and influences many other agronomically important traits. We constructed a physical contig spanning the Q locus using a Triticum monococcum BAC library. Three chromosome walking steps were performed by complete sequencing of BACs and identification of low-copy markers through similarity searches of database sequences. The BAC contig spans a physical distance of ∼300 kb corresponding to a genetic distance of 0.9 cM. The physical map of T. monococcum had perfect colinearity with the genetic map of wheat chromosome arm 5AL. Recombination data in conjunction with analysis of fast neutron deletions confirmed that the contig spanned the Q locus. The Q gene was narrowed to a 100-kb segment, which contains an APETALA2 (AP2)-like gene that cosegregates with Q. AP2 is known to play a major role in controlling floral homeotic gene expression and thus is an excellent candidate for Q.

A bacterial artificial chromosome based physical map of the Ustilago maydis genome

Genome ◽  
2005 ◽  
Vol 48 (2) ◽  
pp. 207-216 ◽  
Author(s):  
Khalid Meksem ◽  
Jeffry Shultz ◽  
Faiza Tebbji ◽  
Aziz Jamai ◽  
Jürgen Henrich ◽  
...  
Keyword(s):  
Bacterial Artificial Chromosome ◽  
Gel Electrophoresis ◽  
Physical Map ◽  
Artificial Chromosome ◽  
Ustilago Maydis ◽  
Pulsed Field Gel Electrophoresis ◽  
Pulsed Field ◽  
Artificial Chromosomes ◽  
Bac Clones ◽  
Copy Dna

Ustilago maydis, a basidiomycete, is a model organism among phytopathogenic fungi. A physical map of U. maydis strain 521 was developed from bacterial artificial chromosome (BAC) clones. BAC fingerprints used polyacrylamide gel electrophoresis to separate restriction fragments. Fragments were labeled at the HindIII site and codigested with HaeIII to reduce fragments to 50–750 bp. Contiguous overlapping sets of clones (contigs) were assembled at nine stringencies (from P ≤ 1 x 10–6 to 1 x 10–24). Each assembly nucleated contigs with different percentages of bands overlapping between clones (from 20% to 97%). The number of clones per contig decreased linearly from 41 to 12 from P ≤ 1 x 10–7 to 1 x 10–12. The number of separate contigs increased from 56 to 150 over the same range. A hybridization-based physical map of the same BAC clones was compared with the fingerprint contigs built at P ≤ 1 × 10–7. The two methods provided consistent physical maps that were largely validated by genome sequence. The combined hybridization and fingerprint physical map provided a minimum tile path composed of 258 BAC clones (18–20 Mbp) distributed among 28 merged contigs. The genome of U. maydis was estimated to be 20.5 Mbp by pulsed-field gel electrophoresis and 24 Mbp by BAC fingerprints. There were 23 separate chromosomes inferred by both pulsed-field gel electrophoresis and fingerprint contigs. Only 11 of the tile path BAC clones contained recognizable centromere, telomere, and subtelomere repeats (high-copy DNA), suggesting that repeats caused some false merges. There were 247 tile path BAC clones that encompassed about 17.5 Mbp of low-copy DNA sequence. BAC clones are available for repeat and unique gene cluster analysis including tDNA-mediated transformation. Program FingerPrint Contigs maps aligned with each chromosome can be viewed at http://www.siu.edu/~meksem/ustilago_maydis/.Key words: Ustilago maydis, physical map, bacterial artificial chromosomes, whole-genome sequencing.

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