Plant, Animal & Microbe Genomes X Conference Plant, Animal & Microbe Genomes X ConferenceJanuary 12-16, 2002
Town & Country Convention Center
San Diego, CA
Workshop: Cattle/Sheep
Over the past years, intensive international efforts have produced genetic, cytogenetic and radiation hybrid maps of the bovine genome (http://locus.jouy.inra.fr). However, despite the large number of mapped genes (over 1200) and the availability of a relatively dense network of genetically mapped markers (over 2300), positional cloning of economic trait loci is hampered by the lack of large insert clones in the region of interest. Here we describe the construction of a first generation physical map of the bovine genome using fingerprinting and PCR screening methods. The INRA bovine BAC library (4 genome equivalent) was fingerprinted as follows : DNA of each of the 105 984 clones was prepared and digested with the restriction enzymes HindIII and HaeIII (Promega), fragments were labelled with ddATP (R110, R6G or Tamra) using Sequenase II (Pharmacia), after purification, fragments were separated on a MegaBace 1000 (Pharmacia) and the profiles were analyzed using the Genetic Profiler software (Pharmacia). A homemade software was used to reduce background and hand on control was performed for every profile. 90 000 fingerprint patterns were then analyzed using the FPC software (http://www.sanger.ac.uk). A contig built with raw data for the 90 000 BAC clones was completed with cutoff values of 10e-8 : 15 000 contigs were observed with an average of 4-5 clones per contig. In a parallel effort, the BAC library is currently being screened by PCR with microsatellite markers and genes in order to anchor the contig on the maps already available. More than 600 STSs have been screened resulting in 2500 BACs identified. These results represent preliminary data towards the construction of a physical map of the bovine genome. Integrated to the ongoing effort with other BAC libraries (http://www.bcgsc.bc.ca/projects/bovine_mapping) the collection of overlapping clones will constitute in the near future a powerful tool for the bovine genome community.