Chromosome restriction mapping

Eig. 5. Restriction map of the yeast artificial chromosome (YAC) vector used for cloning very large fragments of eukaryotic DNA. Terms defined in text... 

Figure 2. Restriction map of the A. aculeatus rhgA genomic clone plM803. pIM803 contains a 3.9-kb chromosomal Ba/nHI-Sa/1 fragment in pBluescriptSK(-l-). The open reading frame is indicated as closed bars. 5 - and 3 - untranslated sequences and introns are given as open boxes.

Archaeal chromosomes have been shown to be circular in three cases. For Thermococcus celer [12], restriction mapping of the entire chromosome with three rare-cutting enzymes clearly demonstrated circularity. Sulfolobus solfataricus DNA gives two... 

The most highly developed genetic map is that of Escherichia coli K12, and it has recently been augmented with coarse [10] and fine [11] restriction maps. As the most nearly complete genetic map it can give us clues to structural features which may be functionally important, especially since some data exist on the effects of chromosomal rearrangements. This makes it a natural reference to which other maps of similar-sized genomes can be compared. 

Restriction maps of entire genomes can be obtained by two approaches. In the top-down approach, infrequently-cutting restriction enzymes and pulsed-field gel electrophoresis are used to map a chromosome much as one would a plasmid. In the bottom-up approach, analysis of many clones in parallel leads to the accumulation of a set of clones which represent the whole genome. Restriction maps of the clones can then be merged to make the genome map. The clones themselves are also a valuable resource. The earliest complete and nearly complete physical mapping projects, both top-down E. co//[10], Schizosaccharomycespombe 19 ) and bottom-up ( . coli[ 1], Saccharomyces cerevisiae[ 2, Caenorhabditis [80,81 ]), were on genomes which were already... 

Ichikawa H., Shimizu K., Saito A., Wang D., Oliva R., Kobayashi H., Kaneko Y., Miyoshi H., Smith C.L., Cantor C.R., Ohki M. (1992). Long-distance restriction mapping of the proximal long arm of human chromosome 21 with Not linking clones. Proc. Natl. Acad. Sci. USA 89 23-27. 

Taylor, D.P., Cohen, S.N., Qark, W.G., and Marrs, B.L. (1983) Alignment of genetic and restriction maps of the photosynthesis region of the Rhodopseudomonas capsulata chromosome by a conjugation-mediated marker rescue technique. J. Bacteriol. 154,580 - 590. 

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