title: Chromosomal duplication in Giardia duodenalis.
abstract: Strains of Giardia duodenalis from diverse parts of the world have three or four chromosomal bands in the range of 650-800 kb as defined by field inversion gel electrophoresis. The extra chromosome band in this range defined a group of strains which are geographically distinct from other strains missing this band. The cloned line WB-1B has three chromosome bands in this size range and chromosome band 3 was used to construct a library of chromosome-specific probes. In some strains examined, including BRIS/83/HEPU/106, a subset of these WB-1B probes hybridized to chromosome band 3 and to the extra chromosome band 4, indicating a partial duplication of chromosome 3 in BRIS/83/HEPU/106. This duplication was estimated to be at least 500 kb when the sizes of NotI chromosome segments which hybridized with chromosome band 3-specific probes were added. A second subset of WB-1B chromosome 3-specific probes hybridized to a fifth chromosome of strain BRIS/83/HEPU/106, in the size range 650-800 kb, which was not visible by ethidium bromide staining. The two subsets of WB-1B probes hybridized to a variety of chromosome combinations in this size range in other Giardia strains and included apparent reversal of chromosome 3 and 4 mobility as well as identification of other minor chromosomes. These data indicate that chromosome band 3 of the line WB-1B is a cluster of at least two different chromosomes that cannot be electrophoretically separated but genetic rearrangements in other strains allow separation of linkage groups carried by chromosome band 3 of WB-1B.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Bancroft Centre, Queensland Institute of Medical Research, Brisbane, Australia.
authors.forename: J A
authors.initials: JA
authors.lastname: Upcroft
authors.forename: A
authors.initials: A
authors.lastname: Healey
authors.forename: P
authors.initials: P
authors.lastname: Upcroft
mesh_terms: D000818:Animals; D002869:Chromosome Aberrations; D015342:DNA Probes; D016054:DNA, Protozoan / Q000235:genetics / Q000378:metabolism; D015252:Deoxyribonucleases, Type II Site-Specific / Q000378:metabolism; D014644:Genetic Variation; D015698:Genomic Library; D016829:Giardia lamblia / Q000235:genetics*; D005810:Multigene Family; D009693:Nucleic Acid Hybridization; D013045:Species Specificity
chemical_list: D015342:DNA Probes; D016054:DNA, Protozoan; D015252:Deoxyribonucleases, Type II Site-Specific; C038565:GCGGCCGC-specific type II deoxyribonucleases; C029312:GGTACC-specific type II deoxyribonucleases