We report the most extensive physically anchored linkage map for cattle produced to date. Three-hundred thirteen genetic markers ordered in 30 linkage groups, anchored to 24 autosomal chromosomes (n = 29), the X and Y chromosomes, four unanchored syntenic groups and two unassigned linkage groups spanning 2464 cM of the bovine genome are summarized. The map also assigns 19 type I loci to specific chromosomes and/or syntenic groups and four cosmid clones containing informative microsatellites to chromosomes 13, 25 and 29 anchoring syntenic groups U11, U7 and U8, respectively. This map provides the skeletal framework prerequisite to development of a comprehensive genetic map for cattle and analysis of economic trait loci (ETL).

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Fas (APO-1, CD95), a member of the tumor necrosis factor (TNF) receptor superfamily, is a cell membrane protein that mediates programmed cell death (apoptosis). In an effort to characterize the possible role of Fas-mediated apoptosis in some important physiological processes in livestock, bovine Fas (bFas) cDNA was isolated and its nucleotide sequence determined. The predicted amino acid sequence encodes a 323-amino-acid protein that contains a leader peptide, a transmembrane domain, and three domains of cysteine-rich motif within the extracellular region. At the amino acid level, bFas is 57% and 50% identical to human (hFas) and mouse (mFas), respectively. Its expression is abundant in peripheral blood lymphocytes, lung, spleen, thymus, and ovary, but minimal in heart, liver, and brain. A polyclonal anti-bFas serum raised against the carboxy-terminal half of cysteine-rich motif I recognized a single 46-kD protein in bovine MDBK cells by Western blot analysis. To investigate the apoptotic activity of bFas, MDBK and bFas-transfected L929 cells were exposed to a monoclonal anti-hFas IgM. Unlike other cell culture systems, the antibody failed to trigger cell death in MDBK and bFas transfected L929 cells.

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The cell-surface protein Fas (APO-1) is a member of the tumor necrosis factor receptor (TNFR) superfamily and transduces apoptosis following binding of Fas ligand or exposure to certain anti-Fas antibodies. We have isolated the bovine Fas (bFas) gene and determined its genomic organization and chromosomal location. Our data indicate that bFas is a single-copy gene that contains 9 exons and spans approximately 31.5 kb. The 5'-flanking region lacks conventional TATA and CCAAT elements, but contains several putative regulatory elements, including multiple copies of Sp1, AP-2, E-box, and N-box consensus sites. Linkage analysis of two (CA) dinucleotide repeat microsatellites within intron 1 and physical assignment by fluorescence in situ hybridization (FISH) placed the bFas gene on bovine chromosome 26. Collectively, these data provide a basis for understanding the regulatory mechanisms that control bFas gene expression.

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