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A 3-Mb sequence-ready contig map encompassing the multiple disease gene cluster on chromosome 11q13.1-q13.3.

Despite the presence of several human disease genes on chromosome 11q13, few of them have been molecularly cloned. Here, we report the construction of a contig map encompassing 11q13.1-q13.3 using bacteriophage P1 (P1), bacterial artificial chromosome (BAC), and P1-derived artificial chromosome (PAC). The contig map comprises 32 P1 clones, 27 BAC clones, 6 PAC clones, and 1 YAC clone and spans a 3-Mb region from D11S480 to D11S913. The map encompasses all the candidate loci of Bardet-Biedle syndrome type I (BBS1) and spinocerebellar ataxia type 5 (SCA5), one-third of the distal region for hereditary paraganglioma 2 (PGL2), and one-third of the central region for insulin-dependent diabetes mellitus 4 (IDDM4). In the process of map construction, 61 new sequence-tagged site (STS) markers were developed from the Not I linking clones and the termini of clone inserts. We have also mapped 30 ESTs on this map. This contig map will facilitate the isolation of polymorphic markers for a more refined analysis of the disease gene region and identification of candidate genes by direct cDNA selection, as well as prediction of gene function from sequence information of these bacterial clones.

Chromosome Mapping↗

A rapid and accurate strategy for rice contig map construction by combination of fingerprinting and hybridization.

A rapid and accurate strategy for rice contig map construction was described. Rice BAC library with average insert of 120 kb in length was used as building materials in contig mapping. The contigs of varied lengths ranging from 500 kb to several megabases with sufficient redundancy to ensure the accuracy of the joining between individual BACs were formed by fingerprinting. The contigs were then assigned to and ordered along the chromosomes by various molecular markers through their hybridization against the whole rice genomic library. The accuracy of clone overlaps in contig was further confirmed by the existence in contigs of well fit stacks of marker-lodged clones. He contigs thus obtained covered nearly the rice genome.

Chromosome Mapping↗

A physical map of human chromosome 7: an integrated YAC contig map with average STS spacing of 79 kb.

The construction of highly integrated and annotated physical maps of human chromosomes represents a critical goal of the ongoing Human Genome Project. Our laboratory has focused on developing a physical map of human chromosome 7, a approximately 170-Mb segment of DNA that corresponds to an estimated 5% of the human genome. Using a yeast artificial chromosome (YAC)-based sequence-tagged site (STS)-content mapping strategy, 2150 chromosome 7-specific STSs have been established and mapped to a collection of YACs highly enriched for chromosome 7 DNA. The STSs correspond to sequences generated from a variety of DNA sources, with particular emphasis placed on YAC insert ends, genetic markers, and genes. The YACs include a set of relatively nonchimeric clones from a human-hamster hybrid cell line as well as clones isolated from total genomic libraries. For map integration, we have localized 260 STSs corresponding to Genethon genetic markers and 259 STSs corresponding to markers orders by radiation hybrid (RH) mapping on our YAC contigs. Analysis of the data with the program SEGMAP results in the assembly of 22 contigs that are "anchored" on the Genethon genetic map, the RH map, and/or the cytogenetic map. These 22 contigs are ordered relative to one another, are (in all but 3 cases) oriented relative to the centromere and telomeres, and contain > 98% of the mapped STSs. The largest anchored YAC contig, accounting for most of 7p, contains 634 STSs and 1260 YACs. An additional 14 contigs, accounting for approximately 1.5% of the mapped STSs, are assembled but remain unanchored on either the genetic or RH map. Therefore, these 14 "orphan" contigs are not ordered relative to other contigs. In our contig maps, adjacent STSs are connected by two or more YACs in > 95% of cases. With 2150 mapped STSs, our map provides an average STS spacing of approximately 79 kb. The physical map we report here exceeds the goal of 100-kb average STS spacing and should provide an excellent framework for systematic sequencing of the chromosome.

Chromosome Mapping↗

A 12-Mb complete coverage BAC contig map in human chromosome 16p13.1-p11.2.

We have constructed a complete coverage BAC contig map that spans a 12-Mb genomic segment in the human chromosome 16p13.1-p11.2 region. The map consists of 68 previously mapped STSs and 289 BAC clones, 51 of which-corresponding to a total of 7.721 Mb of genomic DNA-have been sequenced, and provides a high resolution physical map of the region. Contigs were initially built based mainly on the analysis of STS contents and restriction fingerprint patterns of the clones. To close the gaps, probes derived from BAC clone ends were used to screen deeper BAC libraries. Clone end sequence data obtained from chromosome 16-specific BACs, as well as from public databases, were used for the identification of BACs that overlap with fully sequenced BACs by means of sequence match. This approach allowed precise alignment of clone overlaps in addition to restriction fingerprint comparison. A freehand contig drawing software tool was developed and used to manage the map data graphically and generate a real scale physical map. The map we present here is approximately 3.5 x deep and provides a minimal tiling path that covers the region in an array of contigous, overlapping BACs.

Base Sequence↗

PCAP: probe choice and analysis package--a set of programs to aid in choosing synthetic oligomers for contig mapping.

In the program, PCAP, we provide a methodology for choosing synthetic oligonucleotide probes to be used in contig mapping experiments. The package serves the purpose of presenting a series of short oligonucleotides (8-12mers) that are chosen based on constraints with respect to frequency of occurrence within a particular genome and the G+C content of the oligonucleotides. The four programs contained within the package: (i) convert GenBank files to a format useable by the package; (ii) calculate trinucleotide and tetranucleotide frequencies in available sequence data on a particular species; (iii) present the user with upper and lower bounds on the frequencies of hybridization sites for oligonucleotide probes of length 8-12, (iv) allow the user to place constraints on site frequency and G+C content and provides a list of short probe sequences that fit these criteria. These sequences can then be synthetically produced and used in hybridization experiments to carry out contig mapping.

Base Sequence↗

A 120 kilobase resolution contig map of the rice genome.

92% of the rice genome (4.3 x 10(8) bp, 2n = 24) was covered by 631 contigs of various length, which were generated by fingerprinting from a representative and genetically stable bacterial artificial chromosome (BAC) library of the Guang Lu Ai 4 (a O. Sativa variety) genome with the average insert of 120 kb in length. To form the contig map, 565 molecular markers of RFLP, STS, cDNA and anchor set derived from two O. Sativa varieties were by colony hybridization mapped to the contigs, which were then assigned to and ordered along the particular chromosomes according to the marker colinearity. Being highly conserved DNA sequences shared among the genomes of rice, barley, wheat, oat, maize, sorghum and sugar cane, 89 anchor markers mapped help to identify the rice genes through the information provided by the maps of relative genomes, and vice versa. Numerous repeated DNA sequences of various length were identified and mapped to the chromosomes. Physical distances have been determined for hundreds pairs of adjacent markers, which would facilitate the identification by map-based cloning the rice genes of interest. The accuracy of clone overlaps in contigs was further confirmed by the existence in contigs of well fit stacks of marker-lodged clones independently identified by hybridization. Large scale DNA sequencing of individual chromosomes could now be initiated simply by selecting and sequencing the minimally overlapped BAC clones of the contigs.

Alkyl and Aryl Transferases↗

Bacterial contig map of the 21q11 region associated with Alzheimer's disease and abnormal myelopoiesis in Down syndrome.

We present a high-resolution bacterial contig map of 3.4 Mb of genomic DNA in human chromosome 21q11-q21, encompassing the region of elevated disomic homozygosity in Down Syndrome-associated abnormal myelopoiesis and leukemia, as well as the markers, which has shown a strong association with Alzheimer's Disease that has never been explained. The map contains 89 overlapping PACs, BACs, or cosmids in three contigs (850, 850, and 1500 kb) with two gaps (one of 140-210 kb and the second <5 kb). To date, eight transcribed sequences derived by cDNA selection, exon trapping, and/or global EST sequencing have been positioned onto the map, and the only two genes so far mapped to this cytogenetic region, STCH and RIP140 have been precisely localized. This work converts a further 10% of chromosome 21q into a high-resolution bacterial contig map, which will be the physical basis for the long-range sequencing of this region. The map will also enable positional derivation of new transcribed sequences, as well as new polymorphic probes, that will help in elucidation of the role the genes in this region may play in abnormal myelopoiesis and leukemia associated with trisomy 21 and Alzheimer's Disease.

Alzheimer Disease↗

A YAC contig map of Arabidopsis thaliana chromosome 3.

We have constructed a YAC contig map of Arabidopsis thaliana chromosome 3. From an estimated total size of 25 Mb, about 21 Mb were covered by 148 clones arranged into nine YAC contigs, which represented most of the low-copy regions of the chromosome. YAC clones were anchored with 259 molecular markers, including 111 for which linkage information was previously available. Most of the genetic map was included in the YAC coverage, and more than 60% of the genetic markers from the reference recombinant inbred line map were anchored, giving a high level of integration between the genetic and physical maps. The submetacentric structure of the chromosome was confirmed by physical data; 3R (the top arm of the linkage map) was about 12 Mb, and 3L (the bottom arm of the linkage map) was about 9 Mb. This YAC physical map will aid in chromosome walking experiments and provide a framework for large-scale DNA sequencing of chromosome 3.

Arabidopsis↗

A 2-Mb sequence-ready contig map and a novel immunoglobulin superfamily gene IGSF4 in the LOH region of chromosome 11q23.2.

Human chromosome 11q23.2 has been proposed to contain a tumor suppressor gene(s) whose deletion has been associated with cancer of the lung and breast and with neuroblastoma. To analyze the genomic structure and to isolate a candidate tumor suppressor gene from this region, we constructed a 2-Mb sequence-ready contig map using bacteriophage P1 (P1), bacterial artificial chromosome (BAC), and P1-derived artificial chromosome (PAC). The map comprises a contig of 24 overlapping P1, BAC, and PAC clones. To isolate gene fragments from the region, we performed direct cDNA library screening, exon trapping, EST mapping, and genomic sequencing using the P1, BAC, and PAC clones. Sequence analysis of 5 clones, which spans 23% (458,738 bp) of the region, and extensive gene scanning along the entire region revealed that the region is extraordinarily scarce in genes, but we identified one ubiquitously expressed novel gene and one testis-specific gene fragment. The novel gene, which we call IGSF4 (immunoglobulin superfamily 4), is transcribed into a 1.6- or 4.4-kb RNA encoding a 442-amino-acid protein. It shares strong homology with mouse IGSF-B12 and cell adhesion molecules NCAM1 and NCAM2 within their Ig-like C2-type domains. The IGSF4 gene, a novel gene that is shown to be located in the common loss of heterozygosity region, possesses a number of interesting features and may be good candidate for a tumor suppressor gene.

Amino Acid Sequence↗

CMAP: contig mapping and analysis package, a relational database for chromosome reconstruction.

In the contig mapping and analysis package, CMAP, we provide a foundation for reverse genetics by organizing information about DNA fragments obtained from an organism's genome into a physical map. The user can store information about a particular segment of DNA. This information can be both descriptive, such as any genes contained in a particular DNA fragment, or experimental, such as hybridization profiles or restriction digest patterns for comparison with other fragments. The package can then be instructed to update the physical map or provide information on a DNA fragment within the map, such as its location. The user interface is designed to minimize the learning curve associated with database usage, while eliminating the possibility of entering data outside the ranges of fields through error-checking protocols. Queries are currently accomplished by the use of dynamic SQL (structured query language), which gives the user the ability to build queries based on any combination of the attributes contained within the database without requiring that all possible queries be permanently programmed within the query software. In order to eliminate the need for knowledge of SQL, an interface was designed to allow users to build queries by menu choices. Thus, CMAP is a software package supporting a database for both the production and storage of a physical map as well as being the first step toward the production of a physical mapping workstation.

Algorithms↗

YAC contig mapping of six expressed sequences encoded by human chromosome 21.

Six cDNA clones from human chromosome 21 have been mapped in a set of complete YAC contig spanning the entire chromosome 21q. The mapping positions between two STSs on the YAC contig and the NotI coordinates starting from the telomere of 21q were determined for the cDNA clones. The YAC contig mapping positions agree well with those using a comprehensive somatic cell hybrid mapping panel.

Animals↗

FISH mapping and inter-Alu fingerprinting define the YAC contig map around the centromeric region of human chromosome 18.

Previous reports concerning the location of D18S44 with respect to the centromere have been ambiguous. Also, it has not been possible, based on formerly reported markers, to show that contigs WC18.0 and WC18.1 overlap. However, the data presented here definitively show, using FISH technology, that D18S44 (located on WC18.0) maps to proximal 18q. Furthermore, inter-Alu fingerprinting shows a clear overlap between WC18.0 and WC18.1, thereby establishing a complete contig between D18S44 and markers from WC18.1.

Centromere↗

A YAC contig map of the human genome.

A yeast artificial chromosome library containing 33,000 clones with an average insert size of one megabase of human genomic DNA was extensively analysed by several different procedures for detecting overlaps and positional information. We developed an analysis strategy that resulted, after confirmatory tests, in a YAC contig map reliably covering about 75% of the human genome in 225 contigs having an average size of about ten megabases.

Chromosome Mapping↗

Physical calibration of yeast artificial chromosome contig maps by RecA-assisted restriction endonuclease (RARE) cleavage.

Clone-based genome maps can be constructed by determining the presence or absence of sequence-tagged sites (STSs) in a redundant collection of yeast artificial chromosome clones (YACs). While STS-content mapping has proven to be an effective means of ordering clone ends and STSs along chromosomes, the exact physical map positions of these landmarks are not determined. This fundamental weakness can be overcome by RecA-assisted restriction endonuclease (RARE) cleavage, a method that exploits the binding specificity on duplex DNA of a RecA-protein-oligodeoxynucleotide complex to enhance the cleavage specificity of a restriction endonuclease. This technique allows selective cleavage at individual members of a large set of restriction sites. RARE-cleavage mapping was applied to a contig comprising 5 overlapping YACs spanning 580 kb on human chromosome 14. An STS-content map comprising 10 YAC-end specific STSs and one internal STS was constructed. RARE cleavage was performed on 2 YACs that span the entire contig at the EcoRI sites defining the vector-insert junctions of all 5 YACs, as well as at a HhaI site within the STS that was initially used to screen the YAC library for the clones in the contig. The sizes of the RARE-cleavage fragments were measured by pulsed-field gel electrophoresis and used to convert the STS-content map into a true physical map that indicates precise positions of clone ends and STSs.

Base Sequence↗

A bacterial artificial chromosome-based framework contig map of human chromosome 22q.

We have constructed a physical map of human chromosome 22q using bacterial artificial chromosome (BAC) clones. The map consists of 613 chromosome 22-specific BAC clones that have been localized and assembled into contigs using 452 landmarks, 346 of which were previously ordered and mapped to specific regions of the q arm of the chromosome by means of chromosome 22-specific yeast artificial chromosome clones. The BAC-based map provides immediate access to clones that are stable and convenient for direct genome analysis. The approach to rapidly developing marker-specific BAC contigs is relatively straightforward and can be extended to generate scaffold BAC contig maps of the rest of the chromosomes. These contigs will provide substrates for sequencing the entire human genome. We discuss how to efficiently close contig gaps using the end sequences of BAC clone inserts.

Cell Line↗

A fine physical map of Arabidopsis thaliana chromosome 5: construction of a sequence-ready contig map.

A fine physical map of Arabidopsis thaliana chromosome 5 was constructed by ordering the clones from YAC, P1, TAC and BAC libraries of the genome using the sequences of a variety of genetic and EST markers and terminal sequences of clones. The markers used were 88 genetic markers, 13 EST markers, 87 YAC end probes, 100 YAC subclone end probes, and 390 end probes of P1, TAC and BAC clones. The entire genome of chromosome 5, except for the centromeric and telomeric regions, was covered by two large contigs 11.6 Mb and 14.2 Mb long separated by the centromeric region. The minimum tiling path of the chromosome was constituted by a total of 430 P1, TAC and BAC clones. The map information is available at the Web site http://www.kazusa.or.jp/arabi/.

Arabidopsis↗

Contig map of the Parkinson's disease region on 4q21-q23.

We have constructed a yeast artificial chromosome contig (YAC) map of human chromosome 4q21-q23 across the Parkinson's disease region by combining molecular and fluorescence in situ hybridization techniques. This map contains 55 YACs and 51 molecular markers, including 23 polymorphic markers. We have also isolated one P1 and 33 bacterial artificial chromosomes located within this contig. Plasmid libraries were generated from 11 of these BAC and P1 clones, and 614 random plasmid clones were sequenced for a total of about 200 kb. This contig allowed us to precisely determine the location of 18 transcripts within the D4S2460-D4S2986 interval, including the alpha-synuclein gene found to be mutated in some families with Parkinson's disease.

Chromosome Mapping↗