title: Genome size and genetic map of Cowdria ruminantium.
abstract: Cowdria ruminantium is the cause of a serious tick-borne disease of domestic ruminants, known as heartwater or cowdriosis. The organism belongs to the tribe Ehrlichieae:, which contains obligate intracellular pathogens, causing several important animal and human diseases. Although a few C. ruminantium genes have been cloned and sequenced, very little is known about the size, gross structure and organization of the genome. This paper presents a complete physical map and a preliminary genetic map for C. ruminantium. Chromosomal C. ruminantium DNA was examined by PFGE and Southern hybridization. PFGE analysis revealed that C. ruminantium has a circular chromosome approximately 1576 kb in size. A physical map was derived by combining the results of PFGE analysis of DNA fragments resulting from digestion of the whole genome with KSP:I, RSR:II and SMA:I and Southern hybridization analysis with a series of gene probes and isolated macrorestriction fragments. A genetic map for C. ruminantium with a mean resolution of 290 kb was established, the first for a member of the Ehrlichieae: A total of nine genes or cloned C. ruminantium DNA fragments were mapped to specific KSP:I, RSR:II and SMA:I fragments, including the major antigenic protein gene, map-1.
authors.affiliation: Onderstepoort Veterinary Institute, Onderstepoort, 0110, Republic of South Africa1.
authors.forename: E P
authors.initials: EP
authors.lastname: de Villiers
authors.affiliation: Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, WA 99164, USA2.
authors.forename: K A
authors.initials: KA
authors.lastname: Brayton
authors.affiliation: Onderstepoort Veterinary Institute, Onderstepoort, 0110, Republic of South Africa1.
authors.forename: E
authors.initials: E
authors.lastname: Zweygarth
authors.affiliation: Onderstepoort Veterinary Institute, Onderstepoort, 0110, Republic of South Africa1.
authors.forename: B A
authors.initials: BA
authors.lastname: Allsopp
mesh_terms: D000818:Animals; D015139:Blotting, Southern; D002417:Cattle; D004262:DNA Restriction Enzymes / Q000378:metabolism; D016995:Ehrlichia ruminantium / Q000235:genetics*; D016521:Electrophoresis, Gel, Pulsed-Field / Q000379:methods; D016680:Genome, Bacterial; D006357:Heartwater Disease / Q000382:microbiology; D051379:Mice; D020161:Physical Chromosome Mapping
chemical_list: D004262:DNA Restriction Enzymes