Construction, characterization, and preliminary BAC-end sequencing analysis of a bacterial artificial chromosome library of white clover (Trifolium repens L.)

Genome ◽  
2007 ◽  
Vol 50 (4) ◽  
pp. 412-421 ◽  
Author(s):  
Melanie Febrer ◽  
Foo Cheung ◽  
Christopher D. Town ◽  
Steven B. Cannon ◽  
Nevin D. Young ◽  
...  

White clover ( Trifolium repens L.) is a forage legume widely used in combination with grass in pastures because of its ability to fix nitrogen. We have constructed a bacterial artificial chromosome (BAC) library of an advanced breeding line of white clover. The library contains 37 248 clones with an average insert size of approximately 85 kb, representing an approximate 3-fold coverage of the white clover genome based on an estimated genome size of 960 Mb. The BAC library was pooled and screened by polymerase chain reaction (PCR) amplification using both white clover microsatellites and PCR-based markers derived from Medicago truncatula , resulting in an average of 6 hits per marker; this supports the estimated 3-fold genome coverage in this allotetraploid species. PCR-based screening of 766 clones with a multiplex set of chloroplast primers showed that only 0.5% of BAC clones contained chloroplast-derived inserts. The library was further evaluated by sequencing both ends of 724 of the clover BACs. These were analysed with respect to their sequence content and their homology to the contents of a range of plant gene, expressed sequence tag, and repeat element databases. Forty-three microsatellites were discovered in the BAC-end sequences (BESs) and investigated as potential genetic markers in white clover. The BESs were also compared with the partially sequenced genome of the model legume M. truncatula with the specific intention of identifying putative comparative-tile BACs, which represent potential regions of microsynteny between the 2 species; 14 such BACs were discovered. The results suggest that a large-scale BAC-end sequencing strategy has the potential to anchor a significant proportion of the genome of white clover onto the gene-space sequence of M. truncatula.

Genome ◽  
2004 ◽  
Vol 47 (2) ◽  
pp. 239-245 ◽  
Author(s):  
Yaping Qian ◽  
Li Jin ◽  
Bing Su

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.


2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Changqing Liu ◽  
Yuo Guo ◽  
Taofeng Lu ◽  
Hongmei Wu ◽  
Risu Na ◽  
...  

Bacterial artificial chromosome (BAC) libraries have been invaluable tools for the genome-wide genetic dissection of complex organisms. Here, we report the construction and characterization of a high-redundancy BAC library from a very valuable pig breed in China, Wuzhishan miniature pig (Sus scrofa), using its blood cells and fibroblasts, respectively. The library contains approximately 153,600 clones ordered in 40 superpools of 10 × 384-deep well microplates. The average insert size of BAC clones was estimated to be 152.3 kb, representing approximately 7.68 genome equivalents of the porcine haploid genome and a 99.93% statistical probability of obtaining at least one clone containing a unique DNA sequence in the library. 19 pairs of microsatellite marker primers covering porcine chromosomes were used for screening the BAC library, which showed that each of these markers was positive in the library; the positive clone number was 2 to 9, and the average number was 7.89, which was consistent with 7.68-fold coverage of the porcine genome. And there were no significant differences of genomic BAC library from blood cells and fibroblast cells. Therefore, we identified 19 microsatellite markers that could potentially be used as genetic markers. As a result, this BAC library will serve as a valuable resource for gene identification, physical mapping, and comparative genomics and large-scale genome sequencing in the porcine.


2001 ◽  
Vol 14 (3) ◽  
pp. 422-425 ◽  
Author(s):  
Artem E. Men ◽  
Khalid Meksem ◽  
My Abdelmajid Kassem ◽  
Dasharath Lohar ◽  
Jiri Stiller ◽  
...  

We constructed a BAC library of the model legume Lotus japonicus with a 6-to 7-fold genome coverage. We used vector PCLD04541, which allows direct plant transformation by BACs. The average insert size is 94 kb. Clones were stable in Escherichia coli and Agrobacterium tumefaciens.


Author(s):  
Andrzej Kasprzak ◽  
Jan Šafář ◽  
Jaroslav Janda ◽  
Jaroslav Doležel ◽  
Bogdan Wolko ◽  
...  

AbstractThe narrow-leafed lupin possesses valuable traits for environment-friendly agriculture and for the production of unconventional agricultural products. Despite various genetic and environmental studies, the breeding of improved cultivars has been slow due to the limited knowledge of its genomic structure. Further advances in genomics require, among other things, the availability of a genomic DNA library with large inserts. We report here on the construction of the first DNA library cloned in a BAC (bacterial artificial chromosome) vector from diploid Lupinus angustifolius L. cv. Sonet. The high molecular weight DNA used for its preparation was isolated from interphase nuclei that were purified by flow cytometry. The library comprises 55,296 clones and is ordered in 144×384-well microtitre plates. With an average insert size of 100 kb, the library represents six haploid genome equivalents. Thanks to the purification of the nuclei by flow cytometry, contamination with chloroplast DNA and mitochondrial DNA was negligible. The availability of a BAC library opens avenues for the development of a physical contig map and positional gene cloning, as well as for the analysis of the plant’s genome structure and evolution.


2010 ◽  
Vol 10 (1) ◽  
pp. 94 ◽  
Author(s):  
Melanie L Hand ◽  
Noel OI Cogan ◽  
Timothy I Sawbridge ◽  
German C Spangenberg ◽  
John W Forster

Genome ◽  
1997 ◽  
Vol 40 (4) ◽  
pp. 420-427 ◽  
Author(s):  
L. Fredrick Marek ◽  
R. C. Shoemaker

We constructed a soybean bacterial artificial chromosome (BAC) library suitable for map-based cloning and physical mapping in soybean. This library consists of approximately 40 000 clones (4–5 genome equivalents) stored individually in 384-well microtiter dishes. A random sampling of 224 clones yielded an average insert size of 150 kb, giving a 98% probability of recovering any specific sequence. We screened the library for seven single or very low copy genie or genomic sequences using the polymerase chain reaction (PCR) and found between one and seven BACs for each of the seven sequences. When testing the library with a portion of the soybean psbA chloroplast gene, we found less than 1% chloroplast DNA representation. We also screened the library for eight different classes of disease resistance gene analogs (RGAs) and identified BACs containing all RGAs except class 8. We arranged nine of the class 1 RGA BACs and six of the class 3 RGA BACs into individual contigs based on fingerprint patterns observed after Southern probing of restriction digests of the member BACs with a class-specific sequence. This resulted in the partial localization of the different multigene family sequences without precise definition of their exact positions. Using PCR-based end rescue techniques and RFLP mapping of BAC ends, we mapped individual BACs of each contig onto linkage group J of the soybean public map. The class 1 contig mapped to the region on linkage group J that contains several disease resistance genes. The class 1 contig extended approximately 400 kb. The arrangement of the BACs within this contig has been confirmed using PCR. One end of the class 1 contig core BAC mapped to two positions on linkage group J and cosegregated with two class 1 RGA loci, suggesting that this segment is within an area of regional duplication.Key words: bacterial artificial chromosome, BAC library, soybean, contig, resistance gene analog.


Genome ◽  
2006 ◽  
Vol 49 (11) ◽  
pp. 1393-1398 ◽  
Author(s):  
X.F. Wang ◽  
J. Ma ◽  
W.S. Wang ◽  
Y.M. Zheng ◽  
G.Y. Zhang ◽  
...  

As the second most widely cultivated cotton, Gossypium barbadense is well known for its superior fiber properties and its high levels of resistance to Fusarium and Verticillium wilts. To enhance our ability to exploit these properties in breeding programs, we constructed the first bacterial artificial chromosome (BAC) library for this species. The library contains 167 424 clones (49 920 BamHI and 117 504 HindIII clones), with an estimated average insert size of 130 kb. About 94.0% of the clones had inserts over 100 kb, and the empty clones accounted for less than 4.0%. Contamination of the library with chloroplast clones was very low (0.2%). Screening the library with locus-specific probes showed that BAC clones represent 6.5-fold genome equivalents. This high-quality library provides an additional asset with which to exploit genetic variation for cotton improvement.


Genome ◽  
2000 ◽  
Vol 43 (1) ◽  
pp. 199-204 ◽  
Author(s):  
Junqi Song ◽  
Fenggao Dong ◽  
Jiming Jiang

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.


Genome ◽  
1999 ◽  
Vol 42 (6) ◽  
pp. 1176-1182 ◽  
Author(s):  
D Lijavetzky ◽  
G Muzzi ◽  
T Wicker ◽  
B Keller ◽  
R Wing ◽  
...  

A genomic bacterial artificial chromosome (BAC) library of the A genome of wheat has been constructed. Triticum monococcum accession DV92 was selected for this purpose because it is a cultivated diploid wheat and one of the parental lines used in the construction of a saturated genetic map. Leaves from this accession were used to isolate high-molecular-weight DNA from nuclei. This DNA was partially digested with restriction enzyme Hind III, subjected to double size selection, electroeluted and cloned into the pINDIGO451 BAC vector. The library consists of 276 480 clones with an average insert size of 115 kb. Excluding the 1.33% of empty clones and 0.14% of clones with chloroplast DNA, the coverage of this library is 5.6 genome equivalents. With this genome coverage the probability of having any DNA sequence represented in this library is higher than 99.6%. Clones were sorted in 720 384-well plates and blotted onto 15 high-density filters. High-density filters were screened with several single or low-copy clones and five positive BAC clones were selected for further analysis. Since most of the T. monococcum BAC ends included repetitive sequences, a modification was introduced into the classical end-isolation procedure to select low copy sequences for chromosome walking.Key words: bacterial artificial chromosome, BAC library, Triticum monococcum, wheat.


2005 ◽  
Vol 53 (6) ◽  
pp. 389 ◽  
Author(s):  
Natasha Sankovic ◽  
Wayne Bawden ◽  
John Martyn ◽  
Jennifer A. M. Graves ◽  
Kurt Zuelke

With the accelerating recognition of the power of comparative genomics, there is now enormous interest in sequencing the genomes of a broad range of species. Marsupials diverged at an important evolutionary time. The model Australian marsupial, the tammar wallaby (Macropus eugenii), has long been a resource for biological and genetic studies of marsupials, and the availability of a bacterial artificial chromosome (BAC) library will be a valuable resource in these studies. A tammar wallaby BAC library was constructed using pRazorBAC vector. It contains 55 296 clones with an average insert size of 108 kb, representing 2.2 times coverage of the wallaby genome (based on an estimated 2.7 × 109 bp haploid genome size). The library was arrayed in 384-well plates, and spotted in duplicate onto nylon membranes. Screening these membranes has yielded clones containing 34 single-copy genes distributed over the genome, while it failed for only one gene. Each probe isolated 1–12 BAC clones and, to date, no chimeric clones have been found. This BAC library will constitute an invaluable resource for creating physical maps, positional cloning of genes and other sequences in the tammar wallaby, as well as comparative mapping studies in mammals.


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