Restriction mapping

It should be obvious that direct mapping cannot be used to characterise DNA sequences from very large genomes like the human genome. For such applications, specific sequences are identified against a background of a very large number of 

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

Bam HI restriction map giving approximate size (Kb) of the fragments in the 16 Kb xanthan gene cluster... 

Figure 7.11 Restriction map of Xanthomonas campestris xanthan gene cluster. Adapted from R W Vanderslice at at. Genetic engineering of polysaccharide structure In Xanthomonas campestris. In Biomedical and Biotechnological Advances In Industrial Polysaccharides, 1989, Gordon and Breach N Y.

DNA restriction analysis of the corresponding cosmids revealed one common c oRJ fragment of 9.2 kbp. The restriction map of the DNA region covered by the overlapping clones is shown in Fig 1. 

The XE6 DNA was digested with several restriction enzymes and analysed via Southern blots using a probe derived fi-om the pgaW gene. A restriction map of the X.E6 clone revealed that the complete gene should be present on a 3.0 kb EcoRl fi agment (see Fig. 1). 

Figure 1. The detailed restriction map of the 3.0 kb EcdFl fragment of the XE6 clone. The position of pgaE gene is shown by the black bar. This fragment was cloned into pBluescript SK and further analysed.

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.

Figure 9.8 The construction of restriction maps. The relative position of cleavage sites for two hypothetic restriction enzymes is illustrated for a 12 kb piece of DNA.

A restriction map shows the location of restriction sites in a given DNA sequence. 

A RESTRICTION MAP is used to identify and locate specific restriction sites on a given piece of DNA. The size of a fragment is determined by running the restriction digest on an agarose gel. Fragments separate by size—the smaller ones move farther toward the bottom of the gel. 

Producing restriction maps for gene mapping (Chapter 4, Medical Genetics)... 

The left vertical line is the Thom isomorphism, and the right one is given by the restriction maps. From the dehnition of the Thom isomorphism, we know that the composite map... 

Fig. 3. Restriction Maps of pMAHl and Its Derivatives. Deleted areas are indicated with dotted lines.

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