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[
Worm Breeder's Gazette,
1992]
We are continuing to map clones by fingerprinting, where appropriate. Polytene YAC filters are an additional mapping resource, not a replacement. Thus any clones that require mapping should be sent to Cambridge initially (preferably DNA and clone). There is greater than a 90% probability that a clone will be mapped by fingerprinting, provided that it has sufficient HindIII sites (generally more than 2 or 3) to generate an adequate fingerprint (i.e. essentially all cosmids and lambdas). Clones with insufficient HindIII sites for unequivocal mapping solely by fingerprinting ( many plasmids for example) may be mapped to the cosmid level by a combination of fingerprinting and polytene YAC probing (when the fingerprint comparison is to a smaller subset of cosmids as defined by the probing).
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[
International C. elegans Meeting,
1995]
Twelve contigs of cosmids and yeast artificial chromosomes (YACs) span more than 95Mb of the 100Mb C.elegans genome. 650 markers link the physical and genetic maps.Hybridisation of tag-sequenced cDNA clones to a map-representative set of YACs indicates that the map incorporates in excess of 99.8% of genes. The map is accessible in ACeDB. We (S.C.) are investigating the representation by bacterial artificial chromosomes (BACs) of regions of the genome not represented by cosmids. Two grids of YACs, of 958 clones ('Poly2') and 223 clones ('Suppoly') are available on request. The latter represents regions of the genome that have been characterised or better defined since the selection of clones for the former. Cosmid clones and YAC grids are available from the Sanger Centre (requests to alan@sanger.ac.uk; FAX 01223 494919). YAC clones and 'cm' series cDNA clones are available from the Sanger Centre or Washington University (rw@nematode. wustl.edu; FAX 314 362 2985).
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[
Methods Cell Biol,
1995]
The clone-based physical map of the 100-Mb Caenorhabditis elegans genome has evolved over a number of years. Although the detection of clone overlaps and construction of the map have of necessity been carried out centrally, it has been essentially a community project. Without the provision of cloned markers and relevant map information by the C. elegans community as a whole, the map would lack the genetic anchor points and coherent structure that make it a viable entity. Currently, the map consists of 13 mapped contigs totaling in excess of 95 Mb and 2 significant unmapped contigs totaling 1.3 Mb. Telomeric clones are not yet in place. The map carries 600 physically mapped loci, of which 262 have genetic map data. With one exception, the physical extents of the remaining gaps are not known. The exception is the remaining gap on linkage group (LG) II. This has been shown to be bridged by a 225-kb Sse83871 fragment. Because the clones constituting the map are a central resource, there is essentially no necessity for individuals to construct cosmid and yeast artificial chromosome (YAC) libraries. Consequently, such protocols are not included here. Similarly, protocols for clone fingerprinting, which forms the basis of the determination of cosmid overlaps and the mapping of clones received from outside sources and has to be a centralized operation, and YAC linkage are not give here. What follows is essentially a "user's guide" to the physical map. Details of map construction are given where required for interpretation of the map as distributed. The physical mapping has been a collaboration between the MRC Laboratory of Molecular Biology, Cambridge, United Kingdom (now at The Sanger Centre, Cambridge, UK) and Washington University School of Medicine, St. Louis, Missouri. Inquiries regarding map interpretation, information, and materials should be addressed to alan@sanger.ac.uk or rw@nematode.wustl.edu.
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[
Zootaxa,
2022]
Rhagovelia medinae sp. nov., of the hambletoni group (angustipes complex), and R. utria sp. nov., of the hirtipes group (robusta complex), are described, illustrated, and compared with similar congeners. Based on the examination of type specimens, six new synonymies are proposed: R. elegans Uhler, 1894 = R. pediformis Padilla-Gil, 2010, syn. nov.; R. cauca Polhemus, 1997 = R. azulita Padilla-Gil, 2009, syn. nov., R. huila Padilla-Gil, 2009, syn. nov., R. oporapa Padilla-Gil, 2009, syn. nov, R. quilichaensis Padilla-Gil, 2011, syn. nov.; and R. gaigei, Drake Hussey, 1947 = R. victoria Padilla-Gil, 2012 syn. nov. The first record from Colombia is presented for R. trailii (White, 1879), and the distributions of the following species are extended in the country: R. cali Polhemus, 1997, R. castanea Gould, 1931, R. cauca Polhemus, 1997, R. gaigei Drake Hussey, 1957, R. elegans Uhler, 1894, R. femoralis Champion, 1898, R. malkini Polhemus, 1997, R. perija Polhemus, 1997, R. sinuata Gould, 1931, R. venezuelana Polhemus, 1997, R. williamsi Gould, 1931, and R. zeteki Drake, 1953.
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[
International C. elegans Meeting,
1991]
We have developed a polymorphic genetic STS map which includes 37 sites scattered over the six linkage groups. In many cases the assays can be combined into a single reaction so that multiple sites can be followed simultaneously. By using this map new mutations can be mapped rapidly to a small interval through analysis of the progeny of a single cross. To develop the map we exploited Tcl polymorphisms between the low copy number Bristol and high copy number Bergerac strains. In addition to previously identified sites we have located 80 Tcl containing sites by fingerprinting genomic clones from a Bergerac library to the physical map. Each PCR assay was designed to behave as a dominant genetic marker that gives a product of defined length from the 'filled' Tcl site in Bergerac DNA, but gives no product from the corresponding 'empty' site in Bristol DNA. This was accomplished by determining flanking sequence, and synthesizing an oligonucleotide primer for use in combination with a primer within Tcl. Since the reaction products from different sites were designed to be of different lengths, multiple sites can be assayed in a single reaction. We have used the polymorphic STS markers to map several lethal mutations. Bristol/Bergerac hybrid hermaphrodites are allowed to self and individual homozygous mutant progeny are selected for PCR. The first 20 - 30 animals are tested against markers from all five autosomes to assign the mutation to a linkage group. Additional animals are then assayed with a chromosome specific marker set to determine position along the chromosome. The polymorphic STS map should also be useful for mapping suppressor mutations and mapping loci involved in polygenic traits. In addition to genetic linkage data the map has improved the local contiguity of the genetic and physical maps.
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[
Genetics,
1992]
We devised an efficient genetic mapping system in the nematode Caenorhabditis elegans which is based upon the differences in number and location of the transposable element Tc1 between the Bristol and Bergerac strains. Using the nearly completed physical map of the C. elegans genome, we selected 40 widely distributed sites which contain a Tc1 element in the Bergerac strain, but not in the Bristol strain. For each site a polymerase chain reaction assay was designed that can distinguish between the Bergerac Tc1-containing site and the Bristol "empty" site. By combining appropriate assays in a single reaction, one can score multiple sites within single worms. This permits a mutation to be rapidly mapped, first to a linkage group and then to a chromosomal subregion, through analysis of only a small number of progeny from a single interstrain cross.
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[
Worm Breeder's Gazette,
1992]
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[
Worm Breeder's Gazette,
1993]
See Figures 1-6
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[
Worm Breeder's Gazette,
1992]
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[
Bioessays,
1991]
During the past decade, it has become apparent that it is within our grasp to understand fully the development and functioning of complex organisms. It is widely accepted that this undertaking must include the elucidation of the genetic blueprint - the genome sequence - of a number of model organisms. As a prelude to the determination of these sequences, clone-based physical maps of the genomes of a number of multicellular animals and plants are being constructed. Yeast artificial chromosome (YAC) vectors, by virtue of their relatively unbiased cloning capabilities and capacity to carry large inserts, have come to play a central role in the construction of these maps. The application of YACs to the physical map of the Caenorhabditis elegans genome has enabled cosmid clone 'islands' to be linked together in an efficient manner. The long-range continuity has improved the linkage between the genetic and physical maps, greatly increasing its utility. Since the genome can be represented by a relatively small number of YACs, it has been possible to make replica filters of genomically ordered YACs available to the community at large.