Veterinary medicine. Molecular genetics arrives on the farm.
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Animals↗
Biomedical subjects
J E Womack
Publications and source records attributed to J E Womack.
Somatic cell mapping of T-cell receptor CD3 complex and CD8 genes in cattle.
Bovine genes encoding T-cell receptor, CD3, and CD8 molecules have been mapped to syntenic groups using bovine x rodent hybrid somatic cells. T-cell receptor alpha and delta chains were assigned to bovine syntenic group U5, and the beta and gamma genes were syntenic with each other and with markers on U13. CD3E and CD3D genes were syntenic with each other and located to bovine syntenic group U19. CD8 was most concordant with markers of syntenic group U16, although the concordancy was only 85% and the assignment must be regarded as tentative. The comparative gene maps of human chromosome 7, bovine syntenic group U13, and mouse chromosomes 6 and 13 suggest extensive evolutionary conservation.
Animals↗
RASA contains a polymorphic microsatellite and maps to bovine syntenic group U22 on chromosome 7q2.4-qter.
The bovine gene for the p21ras protein activator (RASA) includes in its 5' untranslated region a (TG)n repeat. Analysis of this (TG)n repeat by PCR amplification of genomic DNA revealed a four-allele polymorphism. A cDNA probe was used to assign RASA to the region 2.4-qter of bovine Chromosome (Chr) 7 by in situ hybridization. PCR analysis of a panel of somatic hybrid lines allowed the assignment of RASA to the unassigned syntenic group 22 (U22) and thus localizes U22 on Chr 7.
Animals↗
Syntenic mapping and chromosomal localization of bovine alpha and beta interferon genes.
The previous assignment of bovine alpha-(IFNA) and beta-(IFNB) interferon gene families to syntenic group U18 was confirmed with additional cDNA probes and a bovine-rodent hybrid somatic cell panel representing all 29 bovine autosomal syntenic groups. Fluorescent in situ hybridization (FISH) localized these genes to bovine Chromosome (Chr) 8 band 15 and demonstrates that with biotinylated plasmids, as few as five tandemly arrayed sequences can be detected by conventional fluorescent microscopy. This technique can be applied to physical mapping of other multicopy genes in domestic animals.
Animals↗
Somatic cell mapping of the bovine interferon-alpha receptor.
The bovine interferon-alpha receptor (BoIFN-alpha R) mediates the activity of bovine IFN-alpha s and IFN-beta. In addition, human IFN-alpha s have uniformly high biological activity on bovine cells. A 32P-labeled derivative of human recombinant IFN-alpha A (HuIFN-alpha A-P1) binds well and can form a characteristic 130-kDa complex on bovine cells, but not on hamster cells. We have, therefore, analyzed the binding and covalent crosslinking of [32P]HuIFN-alpha A-P1 to a panel of bovine-hamster somatic cell hybrids. Binding to several bovine-hamster hybrid cell lines was strong (about 30-50% of that seen with bovine MDBK cells) and specific. The binding correlated uniquely with bovine syntenic group U10. In several of the hybrid lines, the ability of human IFN-alpha B to enhance the expression of endogenous MHC class I molecules correlated with the binding results. We thus conclude that the bovine IFN-alpha R structural gene (locus designation IFNAR) localizes to syntenic group U10. This group includes a number of other genes whose homologs map to human Chromosome (Chr) 21.
Animals↗
Assignment of eight loci to bovine syntenic groups by use of PCR: extension of a comparative gene map.
The polymerase chain reaction (PCR) has been combined with hybrid somatic cell technology to extend the bovine physical map. Eight bovine loci--glycoprotein hormone alpha (CGA), coagulation factor X (F10), chromogranin A (CHGA), low-density lipoprotein receptor (LDLR), human prochymosin pseudogene (CYM), oxytocin (OXT), arginine-vasopressin (ARVP), and cytochrome oxidase c subunit IV pseudogene (COXP)--were assigned to bovine syntenic groups with this approach. CGA was assigned to bovine syntenic group U2, F10 to U27, CHGA to U4 [bovine Chromosome (Chr) 21], LDLR to U22, CYM to U6, OXT and ARVP to U11, and COXP to U3 (bovine Chr 5). Seven of these genes, CGA, F10, CHGA, LDLR, OXT, ARVP, and CYM, further delineate regions of chromosomal conservation on human Chrs 6, 13, 14, 19, 20, 20, and 1, respectively. CHGA, OXT, and ARVP are unmapped in the mouse. Comparative mapping predicts the mouse CHGA will map to Chr 12, and mouse OXT and ARVP will map to mouse Chr 2. Furthermore, human CYM is predicted to be sublocalized to 1p32-q21. The primers developed for these eight loci will be useful for the development of hybrid somatic cell panels in the future as well as establishing a collection of bovine expressed sequence tags.
Animals↗
Comparative mapping of IGHG1, IGHM, FES, and FOS in domestic cattle.
The immunoglobulin genes have not been genetically characterized as thoroughly in cattle as in other mammals, particularly humans and mice. Comparative gene mapping in mammals suggests that the bovine immunoglobulin heavy chain genes, IGHG4 and IGHM might be syntenic with the FOS oncogene. Interestingly, however, when these genes were assigned to bovine syntenic groups utilizing a panel of bovine: hamster hybrid somatic cells, IGH genes were shown to be syntenic with the FES oncogene rather than FOS. In this study IGH and FES were assigned to Bos taurus chromosome 21 while FOS was assigned to chromosome 10. In addition, bovine-specific immunoglobulin-like sequences were observed in the hybrid somatic cells, and one, IGHML1, was mapped to bovine syntenic group U16. The probes used for somatic-cell mapping were also used to screen a small number of cattle of several different breeds for restriction fragment length polymorphisms. IGHG4 and IGHM were shown to be highly polymorphic, while FOS and FES were not.
Animals↗
Somatic cell mapping of bovine EC-SOD and SOD1L loci.
cDNA probes of human extracellular superoxide dismutase (EC-SOD) and bovine superoxide dismutase 1 (SOD1) genes were hybridized to Southern blots containing genomic DNAs from cow-rodent somatic cell lines segregating bovine chromosomes. The SOD1 probe identified two loci: the coding locus (SOD1), which mapped to bovine U10; and a related locus (SOD1L), which mapped to U11. EC-SOD mapped to bovine U15. The mapping of EC-SOD to human chromosome 4, and our mapping of EC-SOD to U15, further defines a region of extensive syntenic conservation between humans and domestic cows.
Animals↗
Syntenic conservation of HSP70 genes in cattle and humans.
A phage library of bovine genomic DNA was screened for hybridization with a human HSP70 cDNA probe, and 21 positive plaques were identified and isolated. Restriction mapping and blot hybridization analysis of DNA from the recombinant plaques demonstrated that the cloned DNAs were derived from three different regions of the bovine genome. One region contains two tandemly arrayed HSP70 sequences, designated HSP70-1 and HSP70-2, separated by approximately 8 kb of DNA. Single HSP70 sequences, designated HSP70-3 and HSP70-4, were found in two other genomic regions. Locus-specific probes of unique flanking sequences from representative HSP70 clones were hybridized to restriction endonuclease-digested DNA from bovine-hamster and bovine-mouse somatic cell hybrid panels to determine the chromosomal location of the HSP70 sequences. The probe for the tandemly arrayed HSP70-1 and HSP70-2 sequences mapped to bovine chromosome 23, syntenic with glyoxalase 1, 21 steroid hydroxylase, and major histocompatibility class I loci. HSP70-3 sequences mapped to bovine chromosome 10, syntenic with nucleoside phosphorylase and murine osteosarcoma viral oncogene (v-fos), and HSP70-4 mapped to bovine syntenic group U6, syntenic with amylase 1 and phosphoglucomutase 1. On the basis of these data, we propose that bovine HSP70-1,2 are homologous to human HSPA1 and HSPA1L on chromosome 6p21.3, bovine HSP70-3 is the homolog of an unnamed human HSP70 gene on chromosome 14q22-q24, and bovine HSP70-4 is homologous to one of the human HSPA-6,-7 genes on chromosome 1.
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Syntenic assignments of visual transduction genes in cattle.
To establish syntenic relationships of phototransduction genes, we have mapped the genes encoding the alpha-, beta-, and gamma-subunits of rod cGMP phosphodiesterase (PDE) (PDEA, PDEB, PDEG), the alpha'-subunit of cone PDE (PDEA2), and the rod cGMP-gated channel (CNCG) to bovine syntenic groups. The rod cGMP PDE alpha-, beta-, and gamma-subunit genes map to bovine syntenic groups U22, U15 (chromosome 6), and U21 (chromosome 19), respectively. The rod cGMP-gated channel gene also maps to syntenic group U15, and the bovine cone alpha'-subunit gene maps to U26 (chromosome 26). With the exception of the cone PDE alpha'-subunit gene, which has not been mapped in other mammals, all of these genes have been assigned to conserved chromosomal regions shared among bovine, human, and mouse. A compilation of currently known syntenic assignments and predictions regarding future assignments of phototransduction genes in human, mouse, and cattle is presented.
3',5'-Cyclic-GMP Phosphodiesterases↗
Linkage relations between A2M, HOX3, INT1, KRAS2, and PAH on bovine chromosome 5.
There is a high level of conservation between human chromosomes and bovine syntenic groups. One such comparison is between human chromosome 12 and bovine chromosome 5, where at least 16 loci have been shown to be conserved in an homologous segment. However, the degree of conservation of order of the loci on bovine chromosome 5 is unknown, and in general the conservation of order in comparisons between humans and cattle can only be speculated. We have estimated the recombination fractions between five of the loci that were previously published as mapping to bovine chromosome 5 by a combination of in situ hybridization and analysis of bovine-rodent somatic cell hybrid lines to determine whether order has been conserved in the homologous segment of bovine chromosome 5 and human chromosome 12. Recombination fractions were estimated in reference pedigrees of cattle. The loci were A2M, GSNL, HOX3, INT1, KRAS2, and PAH. Restriction fragment length polymorphisms for all loci were defined by screening a panel of eight restriction endonucleases. The linkage between loci was estimated using the lod score method, and all possible pairwise comparisons were made. A preliminary map was created by joining together loci that showed the smallest recombination fractions and the largest lod scores. A multipoint analysis was performed to estimate support for the most likely order. This order shows the relative inversion of some of the loci. Moreover, the distance spanned in cattle is less than a quarter the distance spanned in humans. Together, these data indicate that several chromosomal evolutionary events have occurred in the homologous segment shared by humans and cattle.
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Synteny mapping in the bovine: genes from human chromosome 5.
In an effort to generate a more complete bovine syntenic map of Type I comparative anchor loci, seven homologs to genes found on HSA5 were mapped using a panel of bovine x rodent hybrid somatic cells. Five HSA5 genes, CSF2, RPS14, PDGFRB, FGFA, and CSF1R, were assigned to bovine syntenic group U22 (chromosome 7), while two others, C9 and HGMCR, mapped to U10 and U5, respectively. Previous studies had assigned the HSA5 marker SPARC to bovine syntenic group U22. The mapping of genes spanning the length of HSA5 in cattle and also in mouse permits syntenic comparisons between prototypic genomes of three mammalian orders, providing insight into the evolutionary history of this region of the ancestral mammalian genome.
Acyl Coenzyme A↗
Synteny mapping in the bovine: genes from human chromosome 4.
Genes homologous to those located on human chromosome 4 (HSA4) were mapped in the bovine to determine regions of syntenic conservation among humans, mice, and cattle. Previous studies have shown that two homologs of genes on HSA4, PGM2 and PEPS, are located in bovine syntenic group U15 (chromosome 6). The homologous mouse genes, Pgm-1 and Pep-7, are on MMU5. Using a panel of bovine x hamster hybrid somatic cells, we have assigned homologs of 11 additional HSA4 loci to their respective bovine syntenic groups. D4S43, D4S10, QDPR, IGJ, ADH2, KIT, and IF were assigned to syntenic group U15. This syntenic arrangement is not conserved in the mouse, where D4s43, D4s10, Qdpr, and Igj are on MMU5 while Adh-2 is on MMU3. IL-2, FGB, FGG, and F11, which also reside on MMU3, were assigned to bovine syntenic group U23. These data suggest that breaks and/or fusions of ancestral chromosomes carrying these genes occurred at different places during the evolution of humans, cattle, and mice.
Animals↗
Somatic cell mapping, polymorphism, and linkage analysis of bovine prolactin-related proteins and placental lactogen.
The bovine prolactin gene family includes novel members expressed in the fetal placenta that are distinct from placental lactogen. In this study, we investigated the genetic organization of four members of this gene family (PRP1, PRP3, PRP6, and PRP10) as well as placental lactogen (PL). Using a bovine-rodent hybrid somatic cell panel, all five genes were assigned to bovine chromosome 23, which contains prolactin and the major histocompatibility group (BOLA). Restriction fragment length polymorphisms were detected by all probes in breeding populations with the restriction enzyme MspI, whereas no polymorphisms were detected with BamHI. EcoRI, HindIII, TaqI, and PstI produced polymorphic fragments with some but not all of the probes tested. A PRP10 polymorphism, which is apparently the result of a insertion/deletion event, detected polymorphism frequency differences between Bos indicus and Bos taurus. No recombinational events were observed with these probes and prolactin using linkage analysis involving 91 American Holsteins. The bovine prolactin gene family was incorporated into a linkage group containing CYP21. Our studies demonstrate that members of the bovine prolactin gene family have a close physical association with each other, and all members demonstrate genetic variability in the breeding population.
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Ovine and bovine dinucleotide repeat polymorphism at the MAF46 locus.
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Animals↗
New allelic fragment for the growth hormone-TaqI marker in cattle.
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Alleles↗
New allelic fragments for parathyroid hormone-MspI in cattle.
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Alleles↗
Statistical associations between restriction fragment length polymorphisms and quantitative traits in beef cattle.
Data on 41 traits from 677 animals produced in a five-breed diallel were matched with genotypes for five marker-loci provided by restriction fragment length polymorphisms to detect quantitative effects associated with the markers, following three different designs based on inbred lines, half-sib families, and on assumptions of the markers being quantitative trait loci (QTL). Three growth hormone-TaqI alleles, B, C, and D, in high frequencies in this sample of the Brahman breed, were associated with decreases in birth weight, as a maternal trait (P < .01), and decreases in shoulder width at birth (P < .05). Among F2 Angus-Brahman and Brahman-Hereford cows, homozygotes for the B, C, or D alleles gave birth to calves 4.0 kg lighter than cows homozygous for the A allele, an effect that amounts to the magnitude of the corresponding breed difference in the diallel, and represents one phenotypic SD. A putative cytoplasmic effect seems to interact (P = .02) with this effect on maternal birth weight. Also, at birth, F2 calves homozygous for the B, C, or D alleles were .8 cm narrower at the shoulders than those homozygous for the A allele, after adjusting for birth weight. Significant associations (P < .05) between the parathyroid hormone-MspI marker and measures of body size were detected, as well as an effect on weaning weight (P = .03) as a maternal trait, whose magnitude (17.5 kg) equals the Brahman vs Angus and Hereford breed difference, as quantified in the diallel, and represents .8 of a phenotypic SD. No significant associations were found for three other marker-loci (prolactin-MspI, osteonectin-EcoRI, and keratin VI-MspI). Restriction fragment length polymorphisms have the potential to provide new insights and useful applications to animal breeding, but, as in this work, small sample sizes, extreme susceptibility to Type I errors, and different types of possible confounding obfuscate the conclusions that can be drawn from studies of limited scope and less than ideal planning.
Alleles↗