The thyroglobulin gene is syntenic with the MYC and MOS protooncogenes and carbonic anhydrase II and maps to chromosome 14 in cattle

First steps: bovine genomics in historical perspective

The vision of Morris Soller was instrumental in launching the field of bovine genomics. This study is a review of the early years of bovine gene mapping leading up to the sequencing and assembly of the bovine genome in 2009. A historical perspective of parasexual, linkage and physical mapping is provided with a focus on the contribution of these maps to the eventual assignment and orientation of genes and sequence to cattle chromosomes.

Synteny mapping of human chromosome 8 loci in cattle

Four genes having homologous loci on the short arm of human chromosome 8 have been mapped to two different bovine syntenic groups. The gene coding for the tissue-type plasminogen activator mapped with GSR, a human chromosome 8 marker, of syntenic group U14 while lipoprotein lipase and the medium and light neurofilament polypeptide genes were shown to be syntenic with the human chromosome 9 marker GGTB2 of syntenic group U18.

Anchoring of bovine chromosomes 4, 6, 7, 10, and 14 linkage group telomeric ends via FISH analysis of lambda clones

We report the placement of 34 new microsatellite (ms) markers, isolated from a lambda phage genomic clone library, on the bovine genetic map by linkage to published markers. Five of these markers lie at or near the ends of linkage groups and are used to establish chromosomal coverage and orientation. Fluorescence in situ hybridization (FISH) analysis demonstrates that the linkage groups on the U.S. Meat Animal Research Center (MARC) map extend to the telomeric region of Chromosomes (Chrs) 7 and 10. Linkage groups on Chrs 4, 6, and 14 appear to be less inclusive.

Construction of a bovine chromosome 19 linkage map with an interspecies hybrid backcross

Interspecific hybrid backcross animals from a Bos taurus x Bos gaurus F1 female were used to construct a linkage map of bovine Chromosome (Chr) 19. This map includes eight previously unmapped type I anchor loci, CHRNB1, CRYB1, GH1, MYL4, NF1, P4HB, THRA1, TP53, and five microsatellite markers, HEL10, BP20, MAP2C, ETH3, BMC1013, from existing linkage maps. The linkage relationship was determined to be centromere-HEL10-18.8cM-NF1-4.0cM-CRYB1-11 .2cM-(BP20, CHRNB1, TP53)-4.0cM-(MAP2C, GH1, MYL4, THRA1)-14.4cM-P4HB-11.2cM-ETH3-4. 0cM-BMC1013. It was previously revealed that bovine Chr 19 contains the largest known conserved autosomal synteny among human, bovine, and mouse. This study has shown that gene orders within this segment are not conserved among the three species. We propose structural changes in an ancestral mammalian chromosome to account for these differences. This is the first interspecific hybrid backcross used in bovine linkage studies, and it has proven to be an effective tool for incorporating bovine type I loci into the linkage map even with the small sample size presently available. This resource will facilitate the generation of comparative linkage maps that address gene order and effectively predict the locations of unmapped loci across species.

Nonrandom chromosomal abnormalities in bovine lymphoma

Despite detailed knowledge of the genetic map of the bovine leukemia virus (BLV), the mechanism whereby BLV infection results in transformation and B-lineage restriction of tumors is poorly understood. The aim of this study was to gain new insight into pathogenetic mechanisms of BLV-induced tumorigenesis by determining the karyotypes of BLV-associated lymphomas in cattle. Metaphases in cells from lymphoid tumors from 20 mature dairy cows were banded and analyzed after short-term, unstimulated culture. Nineteen out of twenty cases exhibited clonal abnormalities, 17 cases were hyperdiploid, and 16 cases had extremely complex chromosomal changes. Recurrent chromosomal anomalies were identified and there was clear evidence for the evolution of increasing chromosomal instability in 12 cases. The most common abnormalities were the acquisition of additional small chromosomes (23-29); trisomy of chromosomes 5 and 7, and Robertsonian translocations and isochromosome rearrangements involving chromosomes 10, 12, 23, and 26. Monosomy X, trisomy X, and translocations involving the X chromosome were also detected. Chromosomes 2, 3, 4, 6, 8, 9, 11, 13, 14, 19, and 21 were infrequently involved in either structural or numerical changes. Structural rearrangements of chromosomes 10, 12, 23, and 26 may reflect primary abnormalities occurring relatively early in transformation, whereas trisomy 5 may be an extremely common secondary abnormality. While comparison of these findings with the current bovine gene map raises intriguing possibilities for pathogenetic mechanisms, further studies are needed before hypothetical mechanisms linking chromosomal abnormalities with BLV-induced transformation can be made.

Anchored reference loci for comparative genome mapping in mammals

Recent advances in gene mapping technologies have led to increased emphasis in developing representative genetic maps for several species, particularly domestic plants and animals. These maps are being compiled with two distinct goals: to provide a resource for genetic analysis, and to help dissect the evolution of genome organization by comparing linkage relationships of homologous genes. We propose here a list of 321 reference anchor loci suitable for comparative gene mapping in mammals and other vertebrate classes. We selected cloned mouse and human functional genes spaced an average of 5-10 centiMorgans throughout their respective genomes. We also attempted to include loci that are evolutionarily conserved and represented in comparative gene maps in other mammalian orders, particularly cattle and the domestic cat. We believe that the map may provide the basis for a unified approach to comparative analysis of mammalian species genomes.

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.

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.

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.

Mapping HSA 3 loci in cattle: additional support for the ancestral synteny of HSA 3 and 21

Homologs to genes residing on human chromosome 3 (HSA 3) map to four mouse chromosomes (MMU) 3, 6, 9, and 16. In the bovine, two syntenic groups that contain HSA 3 homologs, unassigned syntenic groups 10 (U10) and 12 (U12), have been defined. U10 also contains HSA 21 genes, which is similar to the situation seen on MMU 16, whereas U12 apparently contains only HSA 3 homologs. The syntenic arrangement of other HSA 3 homologs in the bovine was investigated by physically mapping five genes through segregation analysis of a bovine-hamster hybrid somatic cell panel. The genes mapped include Friend-murine leukemia virus integration site 3 homolog (FIM3; HSA 3/MMU 3), sucrase-isomaltase (SI) and glutathione peroxidase 1 (GPX1) (HSA 3/MMU ?), murine leukemia viral (v-raf-1) oncogene homolog 1 (RAF1; HSA 3/MMU 6), and ceruloplasmin (CP; HSA 3/MMU 9). FIM3, SI, and CP mapped to bovine syntenic group U10, while RAF1 and GPX1 mapped to U12.

Evidence for the evolutionary origin of human chromosome 21 from comparative gene mapping in the cow and mouse

To determine the extent of conservation between bovine syntenic group U10, human chromosome 21 (HSA 21), and mouse chromosome 16 (MMU 16), 11 genes were physically mapped by segregation analysis in a bovine-hamster hybrid somatic cell panel. The genes chosen for study span MMU 16 and represent virtually the entire q arm of HSA 21. Because the somatostatin gene (SST), an HSA 3/MMU 16 locus, was previously shown to be in U10, the transferrin gene (TF), an HSA 3/MMU 9 marker, was also mapped to determine whether U10 contains any HSA 3 genes not represented on MMU 16. With the exception of the protamine gene PRM1 (HSA 16/MMU 16), all of the genes studied were syntenic on bovine U10. Thus, all homologous loci from HSA 21 that have been studied in the cow are on a single chromosome. The bovine homolog of HSA 21 also carries several HSA 3 genes, two of which have homologous loci on MMU 16. The syntenic association of genes from the q arm of HSA 3 with HSA 21 genes in two mammalian species, the mouse and the cow, indicates that HSA 21 may have that contained genes now residing on HSA 3. Additionally, the syntenic association of TF with SST in the cow permits the prediction that the rhodopsin gene (RHO) is proximal to TF on HSA 3q.