Genome physical mapping from large-insert clones by fingerprint analysis with capillary electrophoresis: a robust physical map of Penicillium chrysogenum

Abstract

Physical mapping with large-insert clones is becoming an active area of genomics research, and capillary electrophoresis (CE) promises to revolutionize the physical mapping technology. Here, we demonstrate the utility of the CE technology for genome physical mapping with large-insert clones by constructing a robust, binary bacterial artificial chromosome (BIBAC)-based physical map of Penicillium chrysogenum. We fingerprinted 23.1x coverage BIBAC clones with five restriction enzymes and the SNaPshot kit containing four fluorescent-ddNTPs using the CE technology, and explored various strategies to construct quality physical maps. It was shown that the fingerprints labeled with one or two colors, resulting in 40-70 bands per clone, were assembled into much better quality maps than those labeled with three or four colors. The selection of fingerprinting enzymes was crucial to quality map construction. From the dataset labeled with ddTTP-dROX, we assembled a physical map for P.chrysogenum, with 2-3 contigs per chromosome and anchored the map to its chromosomes. This map represents the first physical map constructed using the CE technology, thus providing not only a platform for genomic studies of the penicillin-producing species, but also strategies for efficient use of the CE technology for genome physical mapping of plants, animals and microbes.

Figure 1

Example of a single BIBAC fingerprint generated with five restriction enzymes (the HaeIII fragment ends were not labeled) and four fluorescent-ddNTPs of the SNaPshot Multiplex Ready Reaction Mix on the ABI 3100 DNA analyzer. The blue peaks show the BamHI fragments labeled with ddGTP-dR110; the green peaks show the HindIII fragments labeled with ddATP-dR6G; the black peaks show the XbaI fragments labeled with ddCTP–dTAMRA; the red peaks show the XhoI fragments labeled with ddTTP–dROX; and the orange peaks show the internal size standard LIZ-500.