Abstract
In this study, the genetic and physical mapping of bovine α (IFNA), [β (IFNB), ω (IFNO), trophoblast (IFNT) and Υ (IFNG) interferon gene families, the characterization of individual genes and alleles within each IFN class, and the relationship between IFN genotype and disease resistance was examined. Using a bovine-rodent hybrid somatic cell panel, the previous syntenic assignments for IFNA (U18), EFNB (U18) and IFNG (U3) were verified, and IFNO and IFNT were assigned to bovine syntenic group U18. Syntenic group U18 was subsequently assigned to bovine chromosome 8 by the fluorescent in situ localization of IFNO and IFNT genes to chromosome 8, band 13. With pulsed field gel electrophoresis, physical linkage among IFNA, IFNB, IFNO and IFNT genes was demonstrated. Bovine and ovine IFN restriction fragment length polymorphisms (RFLPs) were identified in Southern blots of genomic DNA using 35 (bovine) and 27 (ovine) probe-enzyme combinations. Following extended electrophoresis, the segregation of bovine RFLPs in 12 probe-enzyme combinations was followed through cattle pedigrees. Codominant segregation of alleles was found for 20 polymorphic IFN loci (5 IFNA, 4 IFNB, 8 IFNO. 2 IFNT and 1 IFNG). A total of 43 IFN genes (10 IFNA, 6 IFNB, 20 IFNO, 6 IFNT and 1 IFNG) were identified in Southern blots of bovine genomic DNA. A provisional genetic map for 8 polymorphic loci was constructed from the analysis of meiotic recombination frequencies in backcross cattle pedigrees. Genetic linkage was not demonstrated between brucellosis resistance and 20 IFN loci in cattle pedigrees segregating resistance to B. abortus as an autosomal dominant trait. However, statistical associations were observed between the presence of specific alleles at 1 IFNB and 2 IFNO loci and the severity of clinical disease following experimental infection with Bovine Herpesvirus-1. A better understanding of the genetic and physical organization of IFN genes in cattle may facilitate the genetic improvement of cattle through selective breeding.
Ryan, Anne Marie (1992). Molecular characterization of interferon genes in cattle. Texas A&M University. Texas A&M University. Libraries. Available electronically from
https : / /hdl .handle .net /1969 .1 /DISSERTATIONS -1293007.