Showing papers by "Alan J. Teale published in 1997"

A medium density genetic linkage map of the bovine genome

Abstract: A cattle genetic linkage map was constructed which covers more than 95 percent of the bovine genome at medium density Seven hundred and forty six DNA polymorphisms were genotyped in cattle families which comprise 347 individuals in full sibling pedigrees Seven hundred and three of the loci are linked to at least one other locus All linkage groups are assigned to chromosomes, and all are orientated with regards to the centromere There is little overall difference in the lengths of the bull and cow linkage maps although there are individual differences between maps of chromosomes One hundred and sixty polymorphisms are in or near genes, and the resultant genome-wide comparative analyses indicate that while there is greater conservation of synteny between cattle and humans compared with mice, the conservation of gene order between cattle and humans is much less than would be expected from the conservation of synteny This map provides a basis for high-resolution mapping of the bovine genome with physical resources such as Yeast and Bacterial Artificial Chromosomes as well as providing the underpinning for the interpolation of information from the Human Genome Project

Localization of genes controlling resistance to trypanosomiasis in mice.

Abstract: Tsetse fly-transmitted trypanosomes (Trypanosoma spp.) cause ‘sleeping sickness’ in man and have a serious impact on livestock-based agriculture in large areas of Africa1. Multigene control of variation in susceptibility to trypanosomiasis is known to occur in mice, where the C57BI/6 (B6) strain is relatively resistant and the A/J (A) and Balb/c (B) strains are susceptible2,3. Such resistance is also well described among several types of west African cattle4. We report here the results of genome-wide scans for genes controlling this trait in the B6 mouse using crosses with two different susceptible strains. Regions on mouse chromosomes 5 and 17 were found to be important in determining resistance in both crosses while an additional region on chromosome 1 showed evidence of involvement in only one cross. We confirmed the size of the effect due to chromosome 17 in F3 intercross populations fixed for alternative parental chromosomes. The three loci are of large effect and account for most of the genetic variation in both F2 populations. We propose that they be designated Tir1, Tir2 and Tir3.

Cloning and sequencing of the tnfa genes of three inbred mouse strains.

Abstract: The C57BL/6, BALB/c, and A/J inbred laboratory mouse strains often express different response phenotypes when challenged with a variety of infectious agents (Morrison et al. 1978; Bradley 1977; Hormmaeche et al. 1985). In view of the pivotal role of tumor necrosis factor Tnfa in innate immunity, we determined the nucleotide sequence of genomic Tnfa DNA of these three mouse strains. Genomic DNA of the three mouse strains C57BL/6, BALB/c, and A/J was obtained from the Jackson Laboratory (Bar Harbor, ME). The DNA was amplified by the polymerase chain reaction (PCR; Seiki et al. 1988) with primers designed from the promoter and the 3’ untranslated (UTR) regions of the published sequence of the C57BL/6 Tnfa gene (Semon et al. 1987). The PCR amplifications were carried out as described earlier (Maga and Richarson 1991). Figure 1 shows the PCR amplification products of the genomic DNAs of the three mouse strains. The amplified products were of the expected size [(approximately 3800 base pairs (bp)]. The PCR-amplified DNAs were cloned in the pMOS vector, using the pMOS Blue T-vector Kit (Amersham, Little Chalfont, England). The nucleotide sequence of the cloned DNA was determined on both strands of each product with the ficomole Sequencing Kit (Stratagene, La Jolla, CA). The complete DNA sequences of the clones were determined using internal primers for sequencing reactions based on the published sequence of the mouse Tnfa gene. Figure 2 shows the complete DNA sequence of the Tnfa genes of the three mouse strains. A number of sequence polymorphisms are apparent at different locations in the genes. Point mutations were found in the introns and exons. A major polymorphism differentiating all three mouse strains was revealed in the microsatellite (AC)n located in the promoter region. [This microsatellite was referred to as a poly(A) repeat by Semon and co-workers (1987)]. A 4 bp deletion was found in the first intron in the A/J strain by comparison with the BALB/c and C57BL/6, while a 3 bp deletion was found in the first intron in the C57BL/6 by comparison with the A/J and BALB/c sequences. A single point mutation in each of the first two exons differentiated the A/J from the other two strains. These mutations would specify Ile in the first exon and Thr in the second exon of the A/J gene and Thr and Ala in these exons, respectively, in the BALB/c and C57BL/6 strains. The polyadenylating signal and the TTATTTAT elements in the 3’UTR, which have been reported to reduce the stability of the mRNA (Shaw and Kamen 1986), are conserved among the three strains. The nucleotide sequence data reported in this paper have been submitted to the GenBank nucleotide sequence database and have been assigned the accession numbers U68414 (A/J), U68415 (BALB/C), and U68416 (C57BL/6)

Genetic mapping of bovine T‐cell receptor complex loci

Abstract: Thymic-derived lymphocytes (T cells) recognize and respond to antigens through the mediation of the T-cell receptor complex. Here we report polymorphism at each of the five loci that encode the different components of the T-cell receptor complex in cattle. These genes were mapped on the bovine genome by genetic linkage analysis in the International Bovine Reference Panel (IBRP). These mapping data provide additional type I markers for linking the bovine genetic map with the human and mouse maps and also permit investigation of the effect of T-cell receptor polymorphism on immune responsiveness and disease susceptibility.

Comparative mapping in cattle of genes located on human Chromosome 18

Abstract: Human Chromosome (Chr) 18 (HSA18) contains approximately85 million base pairs of DNA (Morton 1991). Thirty genes andpseudogenes have been mapped to HSA18 by somatic cell geneticsor in situ hybridization (Le Beau et al. 1993; Overhauser et al.1993; van Kessel et al. 1994). They include pituitary adenylcyclaseactivating peptide (ADCYAP1), laminin a chain (LAMA1), andmitochondrial NADH-ubiquinone reductase, 24 kDa subunit(NDUFV2) on the short arm, and transthyretin (TTR), B-cell lym-phoma 2 (BCL2), plasminogen activator inhibitor type 2 (PAI2),n-cadherin (CDH2), desmocollin type 2 (DSC2), ferrochelatase(FECH), cytochrome b5 (CYB5) and myelin basic protein (MBP)on the long arm (Fig. 1a). The murine homologs of HSA18 geneshave been mapped to at least four chromosomes as follows: Bcl-2and Planh2 genes are on MMU1, thymidylate synthase (Ts1) geneis on MMU5, Lama1 is on MMU17, and the rest are on MMU18(Mouse Genome Database 3.1, 1996).Two bovine genes—Yamaguchi sarcoma viral oncogene ho-molog 1 (YES1) and desmocollin type 1 (DSC1)—homologous toHSA18 loci have been mapped by in situ hybridization to Chr 24(Chowdhary et al. 1996), and ZOO-FISH analyses show thatHSA18 loci are located entirely on BTA24 (Hayes 1995; Toldo etal. 1995; Chowdhary et al. 1996). We report here the genomiclocalization of eight bovine genes homologous to HSA18 genesADCYAP1, CDH2, CYB5, DSC2, FECH, NDUFV2, PAI2, andTTR, using somatic cell genetics and linkage analysis in the In-ternational Bovine Reference Panel (IBRP).Oligonucleotide primers for PCR were designed on the basisof the published nucleotide sequences of sheep or cattle genesADCYAP1, CDH2, CYB5, DSC2, FECH, NDUFV2 and TTR, andwere used to amplify the corresponding DNA fragments frombovine total genomic DNA. Primers for PAI2 gene fragments weredesigned on the basis of a consensus sequence of the human andmurine genes. PCR amplification and single-strand conformationpolymorphism (SSCP) analysis were performed as described pre-viously (Agaba et al. 1996) except that the annealing and geltemperatures were optimized for each DNA fragment as shown inTable 1. The primers for PAI2 were allelic; that is, under optimumPCR conditions amplification of one allele from some individualswas favored over the alternative (null) allele, and, as expected,dominant inheritance was observed in informative IBRP families.Somatic cell hybrid mapping was achieved by PCR amplifica-tion of bovine sequences in a panel of 27 bovine × rodent somaticcell hybrids kindly provided by J. Womack of TexasA&MUniversity. In the case of the PAI2 gene, bovine fragments weredifferentiated from rodent fragments by SSCP analysis. Sevengenes, ADCYAP1, CDH2, CYB5, DSC2, FECH, PAI2 and TTR,segregated 100% concordantly with each other and with Chr 24,while the NDUFV2 gene segregated 100% concordantly with

Sensitivity of segregation analysis to data structure and transformation: a case study of trypanotolerance in mice.

Abstract: Sensitivity of segregation analysis for data structure and data transformation was studied using data from two trials in which mice were challenged at three months of age with a cloned isolate of Trypanosoma congolense and survival time was recorded. Data included records from three inbred strains (C57BL/6 (tolerant), A/J, and BALB/c (both susceptible)) and their crosses. Data were standardized and normalized using a modified power transformation. Segregation analysis was applied to both untransformed and transformed data to determine the genetic inheritance of trypanotolerance in these mice. Data from the two trials were analysed separately and combined. Four genetic models were compared; a one locus model, a polygenic model, a mixed model with common variance, and a mixed model with different variances for each major genotype. Even though the separate data sets and the combined data set all supported the hypothesis of a major gene (or a tightly linked cluster of genes) with different variances within each genotype, parameter estimates were highly sensitive to data transformation and several sets of parameter estimates gave similar likelihood values because of high dependency between parameters. Based on the results segregation analysis can be very sensitive to data structure in a crossbreeding design and to data transformation. Interpretation of the results can be misleading if the entire parameter space is not studied carefully.