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Chez les Mammifères, la différenciation sexuelle résulte d’une cascade complexe dont le premier acteur est le gène SRY, porté par le chromosome Y, qui masculinise la gonade indifférenciée. Cependant, certains individus, en l’absence de SRY, présentent un développement testiculaire et une réversion du sexe. Chez la chèvre, par exemple, la réversion du sexe d’individus XX en l’absence du gène SRY ou d’autres séquences du chromosome Y est étroitement liée à l’absence de corne (mutation motte) puisqu’aucun recombinant n’a jamais été observé. Ce syndrome, nommé PIS pour Polled Intersex Syndrome, est causé par des mutations dans un ou deux gènes autosomiques que nous avons localisés dans un premier temps à proximité de deux marqueurs microsatellites d’origine bovine sur le chromosome 1 caprin. Les cartes génétique, cytogénétique et physique de la région ont ensuite été construites à l’aide, d’une part, de banques d’ADN issues de chromosome 1 trié, des bandes 1q42, 1q43 et 1q44 microdisséquées et de grands fragments (BAC) et, d’autre part, de la cartographie comparée avec les gènes ou EST (expressed sequence tags) localisés dans la région humaine homologue. Ces différentes approches ont permis de localiser le gène PIS au sein d’un contig de 1,5 Mb, dans une région de 100 kb autour d’un marqueur microsatellite.

Although susceptibility to scrapie is largely controlled by the PrP gene, the role of other genes that affect scrapie resistance in sheep is now confirmed. Following the detection of quantitative trait loci (QTL) on chromosomes 6 and 18 in a half-sib family with an ARQ/VRQ susceptible PrP genotype, the whole pedigree of a naturally infected flock was investigated to confirm these QTL regions in different PrP genotypes. The present study has allowed us to confirm the QTL on chromosome 18, and to demonstrate the QTL effects in several PrP genotypes.

International audience

We report an extended river buffalo (Bubalus bubalis, 2n = 50; BBU) cytogenetic map including 388 loci, of which 68 have been FISH-mapped on autosomes in the present study. Ovine and caprine BAC clones containing both type I loci (known genes) and type II loci (simple sequence repeats (SRs), microsatellite marker, sequence-tagged sites (STSs)), previously assigned to sheep chromosomes, have been localized on R-banded river buffalo chromosomes (BBU), which expands the cytogenetic map of this important domestic species and increases our knowledge of the physical organization of its genome. The loci mapped in the present study correspond to loci already localized on homoeologous cattle (and sheep) chromosomes and chromosome bands, further confirming the high degree of chromosome homoeologies among bovids. The comparison of the integrated cytogenetic maps of BBU2p/BBU10 and BBU5p/BBU16 with those of human chromosomes (HSA) 6 and 11, respectively, identified, at least, nine conserved chromosome segments in each case and complex rearrangements differentiating river buffalo (and cattle) and human chromosomes.

Summary Whole-genome radiation hybrid (RH) panels have been constructed for several species, including cattle. RH panels have proven to be an extremely powerful tool to construct high-density maps, which is an essential step in the identification of genes controlling important traits, and they can be used to establish high-resolution comparative maps. Although bovine RH panels can be used with ovine markers to construct sheep RH maps based on bovine genome organization, only some (c. 50%) of the markers available in sheep can be successfully mapped in the bovine genome. So, with the development of genomics and genome sequencing projects, there is a need for a high-resolution RH panel in sheep to map ovine markers. Consequently, we have constructed a 12 000-rad ovine whole-genome RH panel. Two hundred and eight hybrid clones were produced, of which 90 were selected based on their retention frequency. The final panel had an average marker retention frequency of 31.8%. The resolution of this 12 000-rad panel (SheepRH) was estimated by constructing an RH framework map for a 23-Mb region of sheep chromosome 18 (OAR18) that contains a QTL for scrapie susceptibility.

Presented herein is an updated sheep cytogenetic map that contains 452 loci (291 type I and 161 type II) assigned to specific chromosome bands or regions on standard R-banded ideograms. This map, which significantly extends our knowledge of the physical organization of the ovine genome, includes new assignments for 88 autosomal loci, including 74 type I loci (known genes) and 14 type II loci (SSRs/microsatellite marker/STSs), by FISH-mapping and R-banding. Comparison of the ovine map to the cattle and goat cytogenetic maps showed that common loci were located within homologous chromosomes and chromosome bands, confirming the high level of conservation of autosomes among ruminant species. Eleven loci that were FISH-mapped in sheep (B3GAT2, ASCC3, RARSL, BRD2, POLR1C, PPP2R5D, TNRC5, BAT2, BAT4, CDC5L and OLA-DRA) are unassigned in cattle and goat. Eleven other loci (D3S32, D1S86, BMS2621, SFXN5, D5S3, D5S68, CSKB1, D7S49, D9S15, D9S55 and D29S35) were assigned to specific ovine chromosome (OAR) bands but have only been assigned to chromosomes in cattle and goat.

Comparative FISH-mapping among Y chromosomes of cattle (Bos taurus, 2n = 60, BTA, submetacentric Y chromosome), zebu (Bos indicus, 2n = 60, BIN, acrocentric Y chromosome but with visible small p-arms), river buffalo (Bubalus bubalis, 2n = 50, BBU, acrocentric Y chromosome), sheep (Ovis aries, 2n = 54, OAR, small metacentric Y chromosome) and goat (Capra hircus, 2n = 60, CHI, Y-chromosome as in sheep) was performed to extend the existing cytogenetic maps and improve the understanding of karyotype evolution of these small chromosomes in bovids. C- and R-banding comparison were also performed and both bovine and caprine BAC clones containing the SRY, ZFY, UMN0504, UMN0301, UMN0304 and DYZ10 loci in cattle and DXYS3 and SLC25A6 in goat were hybridized on R-banded chromosomes by FISH. The main results were the following: (a) Y-chromosomes of all species show a typical distal positive C-band which seems to be located at the same region of the typical distal R-band positive; (b) the PAR is located at the telomeres but close to both R-band positive and ZFY in all species; (c) ZFY is located opposite SRYand on different arms of BTA, BIN, OAR/CHI Y chromosomes and distal (but centromeric to ZFY) in BBU-Y; (d) BTA-Y and BIN-Y differ as a result of a centromere transposition or pericentric inversion since they retain the same gene order along their distal chromosome regions and have chromosome arms of different size; (e) BTA-Y and BBU-Y differ in a pericentric inversion with a concomitant loss or gain of heterochromatin; (f) OAR/CHI-Y differs from BBU-Y for a pericentric inversion with a major loss of heterochromatin and from BTA and BIN for a centromere transposition followed by the loss of heterochromatin.

Four microsatellite-containing bovine cosmids have been regionally localized by fluorescence in situ hybridization to bovine R-banded chromosome 29 (BTA29) and to the 1;29 translocated chromosomes. PCR-analyses of a somatic hybrid cell panel assigned the four microsatellites to synteny group U7. One of the cosmids (IDVGA7) has been previously mapped to G-banded BTA25 allowing to assign U7 to this chromosome. Hence, it is concluded that G-banded BTA25 corresponds to R-banded BTA29. The occurrence of other misleading nomenclatures for small bovine chromosomes is discussed.

In dairy goats and ewes the use of equine Chorionic Gonadotropin (eCG) as a convenient hormone for the induction of ovulation is necessary for out-of-season breeding and artificial insemination (AI). Treatment for induction and synchronization of ovulation consists of a progestagen delivered by vaginal sponge, followed by an eCG injection. In some females, the first injection of eCG induces a humoral response with high concentrations of anti-eCG antibodies in contrast to other females displaying a very low concentration of anti-eCG antibodies. Females eliciting a low response were also poor responders after the following treatments. Conversely, high responders at the first treatment systematically yielded high immune responses upon the following treatment. By a molecular genetic approach using microsatellites we showed that the anti-eCG immune response phenotypes were associated with MHC class II polymorphism. Females with high residual antibody concentrations at the time of eCG injection exhibited a much lower kidding rate than other females did. Lower fertility of these females, inseminated at a fixed time after eCG treatment (43H for goats and 55H for ewes), might be due to the delay in estrus occurrence and the pre ovulatory LH surge. Consequently, under field conditions old females selected for AI are only those with low residual anti-eCG antibody concentrations and old females with high residual antibody concentration are culled from AI breeding because of their low fertility during the previous year. So we have undertaken comparative studies to establish if the anti-eCG immune response is correlated with the global immunity in animals.

Our on-going goal is to improve and update the comparative genome organization between cattle and man but also among the most detailed mammalian species genomes i.e. cattle, mouse, rat and pig. In this work, we localized 195 genes in cattle and checked all human/bovine non-concordant localizations found in the literature. Next, we compiled all the genes mapped in cattle, goat, sheep and pig (2,166) for which the human ortholog with its chromosomal position is known, added corresponding data in mouse and rat, and ordered the genes relatively to the human genome sequence. We estimate that our compilation provides bovine mapping information for about 89% of the human autosomes. Thus, a near complete, overall and detailed picture of the number, distribution and extent of bovine conserved syntenies (regardless of gene order) on human R-banded autosomes is proposed as well as a comparison with mouse, rat and pig genomes.

Sixty-four genomic BAC-clones mapping five type I (ADCYAP1, HRH1, IL3, RBP3B and SRY) and 59 type II loci, previously FISH-mapped to goat (63 loci) and cattle (SRY) chromosomes, were fluorescence in situ mapped to river buffalo R-banded chromosomes, noticeably extending the physical map of this species. All mapped loci from 26 bovine syntenic groups were located on homeologous chromosomes and chromosome regions of river buffalo and goat (cattle) chromosomes, confirming the high degree of chromosome homeologies among bovids. Furthermore, an improved cytogenetic map of the river buffalo with 293 loci from all 31 bovine syntenic groups is reported.

FOXL2 loss of function in goats leads to the early transdifferentiation of ovaries into testes, then to the full sex reversal of XX homozygous mutants. By contrast, Foxl2 loss of function in mice induces an arrest of follicle formation after birth, followed by complete female sterility. In order to understand the molecular role of FOXL2 during ovarian differentiation in the goat species, putative FOXL2 target genes were determined at the earliest stage of gonadal sex-specific differentiation by comparing the mRNA profiles of XX gonads expressing the FOXL2 protein or not. Of these 163 deregulated genes, around two-thirds corresponded to testicular genes that were up-regulated when FOXL2 was absent, and only 19 represented female-associated genes, down-regulated in the absence of FOXL2. FOXL2 should therefore be viewed as an antitestis gene rather than as a female-promoting gene. In particular, the key testis-determining gene DMRT1 was found to be up-regulated ahead of SOX9, thus suggesting in goats that SOX9 primary up-regulation may require DMRT1. Overall, our results equated to FOXL2 being an antitestis gene, allowing us to propose an alternative model for the sex-determination process in goats that differs slightly from that demonstrated in mice.

Forty autosomal type I loci earlier mapped in goat were comparatively FISH mapped on river buffalo (BBU) and sheep (OAR) chromosomes, noticeably extending the physical map in these two economically important bovids. All loci map on homoeologous chromosomes and chromosome bands, with the exception of COL9A1 mapping on BBU10 (homoeologous to cattle/goat chromosome 9) and OAR9 (homoeologous to cattle/goat chromosome 14). A FISH mapping control with COL9A1 on both cattle and goat chromosomes gave the same results as those obtained in river buffalo and sheep, respectively. Direct G- and R-banding comparisons between Bovinae (cattle and river buffalo) and Caprinae (sheep and goat) chromosomes 9 and 14 confirmed that a simple translocation of a small pericentromeric region occurred between the two chromosomes. Comparisons between physical maps obtained in river buffalo and sheep with those reported in sixteen human chromosomes revealed complex chromosome rearrangements (mainly translocations and inversions) differentiating bovids (Artiodactyls) from humans (Primates).

Le développement des techniques de biologie moléculaire a permis la mise en évidence d’une très importante variabilité de l’ADN tant au niveau chromosomique (remaniements) qu’au niveau nucléotidique (mutations ponctuelles). Les différentes sources de variabilité sont décrites. Les mécanismes potentiellement impliqués dans la genèse de ces polymorphismes sont passés en revue.

International audience; In order to simultaneously integrate linkage and syntenic groups to the ovine chromosomal map, a sheep bacterial artificial chromosome (BAC) library was screened with previously assigned microsatellites using a sheep-hamster hybrid panel and genetic linkage. Thirty-three BACs were obtained, fluorescently labelled and hybridised on sheep-goat hybrid metaphases ($2{\rm n} = 57$). This study allowed us, (i), to anchor all linkage groups on sheep chromosomes, (ii), to give information on the probable position of the centromere on the linkage map for the centromeric chromosomes, (iii), to contradict the previous orientation of the ovine X linkage group by the mapping of BMS1008 on OARXq38. Concerning our somatic cell hybrid panel, this study resulted in the assignment of all the previously unassigned groups to ovine chromosomes and a complete characterisation of the hybrid panel. In addition, since hybridisations were performed on a sheep-goat hybrid, new marker/anchoring points were added to the caprine cytogenetic map.; Ancrage cytogénétique de la carte de liaison et des groupes de synténie par utilisation d'une banque de BAC ovine. Afin d'intégrer, la carte génétique et les groupes de synténies à la carte chromosomique ovine, nous avons criblé, à l'aide de microsatellites, une banque ovine de chromosomes artificiels de bactéries (BAC). Les microsatellites utilisés font partie de la carte de liaison ovine et ont été localisés précédemment dans notre panel d'hybrides somatiques hamster-mouton. Nous avons isolé 33 clones BAC, marqués en fluorescence et hybridés sur métaphase d'un hybride chèvre-mouton ($2{\rm n} = 57$). Les résultats de cette étude ont apporté plusieurs informations. Au niveau de la carte génétique, ces localisations ont permis l'ancrage des groupes de liaison sur les chromosomes ovins et de donner la position la plus probable du centromère sur les groupes de liaison correspondant aux chromosomes métacentriques. De plus, pour le chromosome X, la localisation du microsatellite BMS1008 a permis de corriger l'orientation du groupe de liaison. Au niveau de notre panel d'hybrides somatiques hamster-mouton, ces résultats ont permis d'assigner cytogénétiquement tous les groupes de synténies à un chromosome ovin, aboutissant à une caractérisation approfondie du panel. Enfin, en utilisant des métaphases d'hybride chèvre-mouton pour les hybridations in situ, nous avons pu ajouter de nouveaux marqueurs et points d'ancrages sur la carte chromosomique caprine.

Comparative FISH mapping of river buffalo (Bubalus bubalis, BBU), sheep (Ovis aries, OAR), and cattle (Bos taurus, BTA) X chromosomes revealed homologies and divergences between the X chromosomes in the subfamilies Bovinae and Caprinae. Twenty-four and 17 loci were assigned for the first time to BBU X and OAR X, respectively, noticeably extending the physical map in these two species. Seventeen loci (four of which for the first time) were also FISH mapped to BTA X and used for comparative mapping studies on the three species, which show three morphologically different X chromosomes: an acrocentric (BBU X), an acrocentric with distinct short arms (OAR X), and a submetacentric (BTA X). The same order of loci were found on BTA X and BBU X, suggesting that a centromere transposition, with loss (cattle) or acquisition (river buffalo) of constitutive heterochromatin, differentiated the X chromosomes of these two bovids. Comparison of bovine (cattle and river buffalo) and caprine (sheep) X chromosomes revealed at least five common chromosome segments, suggesting that multiple transpositions, with retention or loss of constitutive heterochromatin, had occurred during their karyotypic evolution.

L. Iannuzzi l , G. P. Di Meo l , A. Perucatti l , L. Schibler 2 , D. Incarnato, L. Ferrara, T. Bardaro 3 & E. P. Cribiu 1 National Research Council (CNR), IABBAM, Via Argine 1085, 80147 Naples, Italy: Fax: +39-081-5965291; E-mail: L.Iannuzzi@ iabbam.na.cnr.i t ; 2 Research Center, INRA, Laboratory of Genetics and Cytogenetics, Department of Animal Genetics, 78352 Jouy-en-Josas, France; E-mail: cribiu@jouy.inra.fr ; 3 National Research Council (CNR), IIGB, Naples, Italy

The regional characterization of a previously obtained hamster-sheep hybrid panel is reported. Using data available from ruminant maps (sheep, cattle, and goat), we have selected a set of 300 markers and have analyzed them by PCR in this hybrid panel. Results obtained for 204 markers show the presence of all sheep chromosomes (including gonosomes) in entire or fragmented form. Analysis of syntenies has given 130 types of answer defining segments of variable sizes. This study has led to the regional characterization of this panel and provides comparative data on a set of bovine and caprine markers. With the level of characterization now achieved for this hybrid panel, the regional assignment of new genes or markers to sheep chromosomes can be rapidly obtained. Finally, this panel will help to collect new data for comparative mapping of domestic animals and to highlight the conservation of syntenic groups between closely related species, that is, sheep, cattle, and goat.

We report the use of dual-colour chromosome painting to determine the exact nature of certain chromosome rearrangements observed in the pig (Sus scrofa domestica). The chromosomal abnormalities were detected by GTG- and RBG-banding techniques. The initially proposed interpretations were: (1) rcp(6;13)(p1.5;q4.1); (2) rcp(11;16)(p1.4;q1.4); (3) rcp(6;16)(p1.1;q1.1); (4) rcp(13;17)(q4.1;q1.1); (5) rcp(6;14)(q2.7;q2.1); (6) rcp(3;5)(p1.3;q2.3); (7) rcp(2; 14)(q1.3;q2.7); (8) rcp(15;17)(q1.3;q2.1). Hybridizations were carried out with biotin- and digoxigenin-labelled probes obtained by priming authorizing random mismatches polymerase chain reaction (PARM-PCR) amplification of porcine flow-sorted chromosomes. In some cases, i.e. (1), (4), (5), (6), (7) and (8), the fluorescence in situ hybridization (FISH) results allowed confirmation of the interpretations proposed with classical cytogenetic methods. Chromosome painting proved the reciprocity of the translocation in cases (1), (6) and (8), whereas modifications of the formula were proposed for case (2). Primed in situ DNA labelling (PRINS) experiments have also been carried out in case (3) using a primer specific for the centromeres of acrocentric chromosomes (first experiment) or a primer specific for the centromeres of a subset of meta- and submetacentric chromosomes including chromosome 6 (second experiment). It allowed us to demonstrate that the breakpoints occurred in the centromeric region of chromosome 16 and in the p arm of chromosome 6, just above the centromere.

A bovine bivariate flow karyotype has been established from a primary fibroblast cell culture carrying a 4;10 Robertsonian translocation. From 27 to 36 populations could be resolved by flow cytometry although the anticipated number was 31. Separation of chromosomal pairs into two populations explains this high resolution and confirms the high level of heteromorphism previously observed. We used a PARM-PCR (Priming Authorizing Random Mismatches) procedure for the production of paint probes from flow-sorted chromosome fractions. These probes were used for chromosome identification by fluorescence in situ hybridization (FISH) on R-banded metaphase spreads. We present the localization of all the bovine chromosome types on the flow karyotype. Twenty-two chromosome types including the translocated chromosome were sorted as pure fractions.

Chantier qualité spécifique "Auteurs Externes" département de Génétique animale : uniquement liaison auteur au référentiel HR-Access; International audience; Natural mutations in the LIPH gene were shown to be responsible for hair growth defects in humans and for the rex short hair phenotype in rabbits. In this species, we identified a single nucleotide deletion in LIPH (1362delA) introducing a stop codon in the C-terminal region of the protein. We investigated the expression of LIPH between normal coat and rex rabbits during critical fetal stages of hair follicle genesis, in adults and during hair follicle cycles. Transcripts were three times less expressed in both fetal and adult stages of the rex rabbits than in normal rabbits. In addition, the hair growth cycle phases affected the regulation of the transcription level in the normal and mutant phenotypes differently. LIPH mRNA and protein levels were higher in the outer root sheath (ORS) than in the inner root sheath (IRS), with a very weak signal in the IRS of rex rabbits. In vitro transfection shows that the mutant protein has a reduced lipase activity compared to the wild type form. Our results contribute to the characterization of the LIPH mode of action and confirm the crucial role of LIPH in hair production.

Contents: The effects of a 6/15 Robertsonian translocation on growth and reproductive performance were investigated. One carrier Saanen buck was compared with 36 non-carrier Saanen sires. No significant effect was observed on daily growth, libido, or siminal characteristics. Fertility rate and prolificacy of the carrier and normal males were 58.3% and 1.53 ± 0.79 (m ± sd) vs 48.9% and 1.36 ± 0.58 respectively (p > 0.05). Kidding rate and prolificacy of 30 normal and 32 heterozygous daughters of this carrier buck were 60% vs 59% (p > 0.05) and 1.47 ± 0.57 vs 1.34 ± 0.48 (p > 0.05) respectively. Normal does always demonstrated a higher prolificacy (p > 0.05) independent of breeding pratices and service rank. Inhalt: Einflus der 6/15 Robertsonschen Translokation bei Saanenziegen Es wurde der Einflus einer 6/15 Robertsonschen Translokation auf Wachstum und Fortpflanzung sleistung untersucht. Ein Tragertier (Saanenbock) wurde mit 36 Nichttragern verglichen. Es wurden keine Effekte hinsichtlich taglichen Wachstums, Libido und Spermacharakteristika festgestellt. Befruchtungsprozentsatz und Nachkommenrate des Tragertieres und der normalen Bocke war 58,3% und 1,53 ± 0,79 gegenuber 1,36 ± 0,58 (p ±0,05). Ablammrate und Nachkommensrate von 30 normalen und 32 heterozygoten Tochtern des Tragerbocks betrugen 60% gegenuber 59% (p ± 0.05) und 1,47 ± 0,57 gegenuber 1,34 ± 0,48 (p ± 0,05). Normale Ziegen zeigen hohere Nachkommensraten (p ± 0,05) unabhangig von Bedeckungspraxis und Besamungsfolge.

The cytogenetic study of 224 AI Saanen and Alpine he-goats revealed the presence of a Saanen animal carrying a Robertsonian translocation. The chromosomes involved in this translocation were determined using G (GTG) and C (CBG) banding techniques. The chromosomes in question were identified as chromosomes 6 and 15., L’étude cytogénétique de 224 boucs d’insémination artificielle de races Saanen et Alpine a permis de mettre en évidence la présence d’un animal de race Saanen porteur d’une translocation robertsonienne. Les chromosomes impliqués dans cette translocation ont été déterminés à l’aide des techniques de marquage G (GTG) et C (CBG). Les chromosomes concernés sont le 6 et le 15.

Although susceptibility to scrapie is largely controlled by the PRNP gene, we have searched for additional genomic regions that affect scrapie incubation time in sheep, using two half-sib families with a susceptible PRNP genotype and naturally infected by scrapie. Quantitative trait loci were detected on OAR6 and OAR18.

Contents Synaptonemal complex analysis of a58, XY, t(1;29),t(9;23) bull showed the presence of two separated trivalent figures, and the absence of association of these trivalents with the sex vesicle. The results of this study confirm that in bulls carrying Robertsonian translocations, there is no “abnormal” behaviour of synaptonemal complexes at pachytene. Inhalt: Analyse des synaptonemalen Komplexverhaltens bei einem Bullen, der eine 1;29 und 9,23 Robertsonsche Translokation aufweist Die synaptonemale Komplexanalyse eines 58,Xt(1;29), t(9;23) Bullen zeigte zwei separate trivalente Konfigurationen. Es fehlte die Verbindung dieser Trivalente mit den Geschlechtsvesikeln. Die Ergebnisse der Arbeit bestatigen, daβ Bullen, die Trager einer Robertsonschen Translokation sind, kein abnormales Verhalten des synaptonemalen Komplexes in Pachyten aufweisen.

Although the European rabbit (Oryctolagus cuniculus) is used both in agronomics and in research, genomic resources for this species are still limited and no microsatellite-based genetic map has been reported. Our aim was to construct a rabbit genetic map with cytogenetically mapped microsatellites so as to build an integrated genetic and cytogenetic map. A reference population of 187 rabbits comprising eight three-generation families with 10-25 offspring per family was produced. One hundred and ninety-four of 305 previously identified microsatellites were included in this study. Of these, 158 were polymorphic with two to seven alleles. The map reported here comprises 111 markers, including 104 INRA microsatellites, five microsatellites from another source and two phenotypic markers (angora and albino). Ninety markers were integrated into 20 linkage groups. The remaining 21 microsatellites mapped to separate linkage groups, 19 with a precise cytogenetic position and two with only a chromosomal assignment. The genetic map spans 2766.6 cM and covers 20 rabbit chromosomes, excluding chromosomes 20, 21 and X. The density of this map is limited, but we used it to verify the location of angora and albino on chromosomes 15q and 1q, respectively, in agreement with previously published data. This first generation genetic/cytogenetic map will help gene identification and quantitative trait loci mapping projects in rabbit.

Routine cytogenetic investigations of the Chianina cattle (BTA) breed revealed the presence of longer and smaller chromosomes than the largest (BTA1) and smallest (BTA29) chromosomes in the cells of a young, normal-looking bull used for reproduction. Application of both RBA-banding and Ag-NOR techniques, as well as the use of the FISH technique and specific molecular markers of both BTA11 (IL1B, ASS and LGB) and BTA21 (SERPINA and D21S45) established that these two abnormal chromosomes were the product of a reciprocal translocation between BTA11 and BTA21. Both der(11) and der(21) were C-band positive and the chromosome regions affected were rcp(11;21)(q28;q12). The young bull had a normal body conformation, including external genitalia, normal levels of testosterone (as in the control) and non-detectable levels of both 17 beta-estradiol and progesterone (as in the control). The animal never showed libido in the presence of both males and females in oestrus. After slaughter at 18 months, histological evaluation revealed normal organized testes, seminiferous tubules and epididymis but with poor proliferative germ cells consisting mainly of spermatogonia, middle pachytene spermatocytes and early spermatids with late spermatids and spermatozoa being very rare.

International audience; A medium-density map of the horse genome (Equus caballus) was constructed using genes evenly distributed over the human genome. Three hundred and twenty-three exonic primer pairs were used to screen the INRA and the CHORI-241 equine BAC libraries by polymerase chain reaction and by filter hybridization respectively. Two hundred and thirty-seven BACs containing equine gene orthologues, confirmed by sequencing, were isolated. The BACs were localized to horse chromosomes by fluorescent in situ hybridization (FISH). Overall, 165 genes were assigned to the equine genomic map by radiation hybrid (RH) (using an equine RH(5000) panel) and/or by FISH mapping. A comparison of localizations of 713 genes mapped on the horse genome and on the human genome revealed 59 homologous segments and 131 conserved segments. Two of these homologies (ECA27/HSA8 and ECA12p/HSA11p) had not been previously identified. An enhanced resolution of conserved and rearranged chromosomal segments presented in this study provides clarification of chromosome evolution history.

The INRA and the CHORI-241 horse BAC libraries were screened by hybridization with DNA probes and/or directly by PCR with primers designed in consensus sequences of genes localized at the end of each human chromosome. BAC clones were retrieved and 36 could be FISH mapped after the expected gene was confirmed in each BAC by sequencing. Our results show that 16 BACs can be considered to be at telomeric or centromeric positions in the horse and 15 were found at the boundary of actually defined conserved segments even-though often located within conserved syntenic fragments between horse and human. There is no straightforward relation between the end position of a marker in human and its end position in the horse. A gene was first anchored to ECA27 by FISH mapping. The localization of these markers expands the cytogenetic map of the horse and will serve as anchors for the integrated and future physical maps. It should also help to better understand the different chromosomal rearrangements that occurred during evolution of genomes derived from a common ancestral karyotype.

In order to increase the number of markers on the horse cytogenetic map and expand the integration with the linkage map, an equine BAC library was screened for genes and for microsatellites. Eighty-nine intra-exon primers were designed from consensus gene sequences in documented species. After PCR screening, 38 clones containing identified genes were isolated and FISH mapped. These data allowed us to refine the available Zoo-FISH results, to define ten new conserved cytogenetic segments and expand two others, thus leading to the identification of a total of 26 conserved segments between horse and human. Interestingly, a new homeology segment was detected between ECA6p and HSA2q. Screening BAC clones for dinucleotide repeats led to the isolation of 33 microsatellites. Ten of the clones each contained at least a polymorphic microsatellite and one specific gene. The success of the approach in the production of integrative anchor loci and their potential use in localization and analysis of traits of interest by the candidate gene and positional cloning approach, are discussed.

X and Y specific probes were identified in order to apply the fluorescent in situ hybridization (FISH) technique to bovine spermatozoa. For Y chromosome detection, the BRY4a repetitive probe, covering three quarters of the chromosome, was used. For X chromosome detection, a goat Bacterial Artificial Chromosome (BAC) specific to the X chromosome of bovine and goats and giving a strong FISH signal was used. Each probe labeled roughly 45% of sperm cells. The hybridization method will be useful for evaluating the ratio of X- and Y- bearing spermatozoa in a sperm sample and consequently can be used to evaluate the efficiency of sperm sorting by different techniques such as flow cytometry.

During normal cytogenetic investigations on the Chianina cattle (BTA) breed, a normal looking young bull was found to carry an abnormal Y chromosome which was a product of a reciprocal translocation between chromosomes Y and 9. This was revealed by both CBA- and RBG-banding techniques and was clearly confirmed by FISH-mapping analysis with IDVGA50 (which paints the complete Yq arm in a normal Y), as well as with AMD1, CGA, IGF2R (mapping to BTA9q16, BTA9q22 and BTA9q27-->q28, respectively) and SRY (mapping to normal BTAYq23). Analysis on sperm from four different samples revealed azoospermia in the carrier, indicating that the rcp(Y;9) induces sterility in the bull. Copyright 2002 S. Karger AG, Basel

Sixteen male Podolian cattle, two sires and their 14 male offspring, were investigated cytogenetically on the basis of a female-like phenotype found in one of them. Eleven male offspring, including the one with female traits, and one of the two sires were found to carry an abnormal Y chromosome which originated from a pericentric inversion of the proximal half of the Yq arm (Yq11→q12.2), as demonstrated by both banding and FISH mapping techniques with Y-specific molecular markers.

The purpose of this study was to increase the number of genes assigned by in situ hybridization to equine chromosomes and thus the number of links for comparative mapping with other species. Forty-four new sequences were added to the horse cytogenetic map by FISH mapping of BAC clones containing genes (35) or ESTs (9). Three approaches were developed: use of horse BAC clones screened with (i) horse EST primers, (ii) interspecific consensus intraexonic primers, and (iii) use of goat BAC containing genes previously localized on goat chromosomes. Present data suggest that the second approach is the most promising. A total of 46 segments containing one or several genes could be compared, among which 40 loci could be included in 16 synteny groups between human and horse, displaying one ordered segment and several breaking points along chromosomes. All single BAC localizations confirm the most recent mapping data. Twenty-six out of 31 chromosomes now contain a gene mapped by in situ hybridization, and 14 new arm-to-arm segment homologies were revealed.

Cytogenetic localization of 24 BACs containing type I (genes and ESTs) and type II (microsatellites) markers were used to construct cytogenetic maps of caprine (CHI) and bovine (BTA) X chromosomes. Comparison of these two maps revealed that the distal region of the goat X long arm (CHI Xq38→q42) was located inside the bovine X chromosome, between PGK1 (BTA Xq25) and DVEPC137 (BTA Xq12). The marker order was globally conserved without any pericentric inversion, as previously postulated in the literature. The caprine centromere was found between DVEPC053 and DVEPC102 (belonging to the same band in the bovine X: BTA Xq41), whereas the bovine centromere was between DVEPC076 and DVEPC132, belonging to the same region of the caprine X chromosome (CHI Xq31→q33). The pseudoautosomal region was situated at the tip of the bovine X long arm and on the tiny short arm of the caprine X chromosome. In the non-pseudoautosomal (NPA) region, the synteny of coding sequences was well conserved between the human species and the two ruminant species, but the gene order was dramatically divergent. It is suggested that the 24 BACs of this study could constitute a new tool to measure phylogenetic distances between different mammalian species by comparing chromosome rearrangements inside the NPA region of the X.

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Thirty-six new horse microsatellites (11 from plasmid libraries and 25 from a cosmid library) were isolated and characterized on a panel of four horse breeds. Thirty were found to be polymorphic with heterozygosity levels ranging between 0.20 and 0.87. Twenty-two of the cosmids were physically mapped to R-banded single horse Chromosomes (Chrs) 1, 3, 4, 9, 11, 12, 13, 15, 18, 19, 21, 22, 23 and three to pericentromeric regions. Furthermore, linkage analysis between a selection of 42 DNA markers, including those presented in this study, and 16 conventional markers of the horse hemotype was performed on six paternal half-sib horse families. Five linkage groups were detected, of which four were assigned to Chr 10, 11, 15, and 18. This work increased by one-third the number of published polymorphic DNA markers suitable for horse mapping and approximately doubled the number of known linkage groups. Our cosmids labeled 14 out of the 31 horse autosomes. Moreover, the physical anchoring of part of these markers will orient linkage and synteny groups on the chromosomes and will contribute to their assignment.

Contrary to other genetic disorders, the genetic study of sex determination anomalies in humans stumbles over the difficulty in observing large pedigrees. In goats, abnormalities in sex determination are intimately linked to a dominant Mendelian gene coding for the "polled" (hornless) character, which could render this species an interesting animal model for the rare human cases of SRY-negative XX males. In this report, we describe genetic linkage between the polled/intersex synchome (PIS) and four microsatellite markers of the distal region of goat Chromosome 1 (CHI1), quite distinct from the bovine "polled" region. According to comparative mapping data, no sex-determining gene has been described so far in homologous regions in the human. This genetic localization constitutes a first step towards identifying a new autosomal sex-determining gene in mammals.

The karyotype of the addax (Addax nasomaculatus, 2n = 58) has been investigated by RBG and CBG banding techniques. All chromosomes are acrocentric except the first pair of autosomes, which is submetacentric. The X chromosome is the largest acrocentric, and the Y chromosome is a medium sized acrocentric. According to the standard conventions used for cattle and goat, p- and q-arms of the pair of submetacentric autosomes correspond, respectively, to chromosomes # 27 # 1. The comparison of banding patterns of chromosomes in addax and four other species of the subfamily Hippotraginae reveals several common features and a high degree of homoeology with caprine and bovine karyotypes.

The extent and distribution of conserved chromosomal segments between pig and cattle chromosomes were established using hybridization of porcine chromosome painting probes on bovine metaphases. A total of 44 segments of conserved synteny were identified, resulting in a nearly complete coverage of the bovine karyotype. This study provides new data on chromosome evolution of mammals.

Numerous loci can be amplified by PARM-PCR on 300 sorted chromosomes in low-stringency conditions (annealing at 30 degrees C during the two first cycles) to produce a probe that can be used in FISH painting experiments. We demonstrate that, depending on the primer chosen for the amplification, patterns of different quality can be obtained. In order to design a primer that allows amplification of coding sequences, we have shown that motifs of at least seven glutamic acid repeats (GAG or GAA codons) are present in human proteins more frequently than expected. Moreover, these repeats do not correspond to triplet expansion and can be conserved between species. Using probes prepared from sorted chromosomes with (GAG)7 primer, we were able to achieve homologous FISH painting on human, porcine, ovine, and bovine species, and bidirectional heterologous FISH painting between human and porcine species. As an example, using probes for human Chromosome (Chr) 19 and porcine Chrs 1 and 6, we clearly defined the regional homologies existing between those chromosomes.

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A genetic map of bovine Chromosome (Chr) 11 (BTA11, synteny group U16) has been constructed from 330 animals belonging to 21 families, which constitute the international bovine reference panel (IBRP). This map is based on 13 polymorphic microsatellite markers, two of which were chosen in previously published maps. Three markers have been isolated from cosmids. Two of the three cosmids have been physically localized by fluorescence in situ hybridization (FISH), to anchor the genetic map on the chromosome. In addition, a biallelic polymorphism in the β-lactoglobulin gene (LGB) has been genetically positioned relative to the microsatellite markers. The most probable order of the markers is: cen-INRA044-BM716-INRA177-(TGLA 327, INRA198, INRA131)-INRA111-INRABERN169-(INRA115, INRA032)-INRA108-INRABERN162-INRA195-LGB. T The total linkage group spans 126 cM, which probably corresponds to most of the chromosome length. The average intermarker distance is about 10.5 cM, allowing the potential detection of a genetic linkage with any Economic Trait Loci (ETL) of this chromosome.

Chantier qualité GA; Background: MicroRNA (miRNA) are negative regulators of gene expression, capable of exerting pronounced influences upon the translation and stability of mRNA. They are potential regulators of normal mammary gland development and of the maintenance of mammary epithelial progenitor cells. This study was undertaken to determine the role of miR-30b on the establishment of a functional mouse mammary gland. miR-30b is a member of the miR-30 family, composed of 6 miRNA that are highly conserved in vertebrates. It has been suggested to play a role in the differentiation of several cell types.[br/] Methodology/Principal Findings: The expression of miR-30b was found to be regulated during mammary gland development. Transgenic mice overexpressing miR-30b in mammary epithelial cells were used to investigate its role. During lactation, mammary histological analysis of the transgenic mice showed a reduction in the size of alveolar lumen, a defect of the lipid droplets and a growth defect of pups fed by transgenic females. Moreover some mammary epithelial differentiated structures persisted during involution, suggesting a delay in the process. The genes whose expression was affected by the overexpression of miR-30b were characterized by microarray analysis.[br/] Conclusion/Significance: Our data suggests that miR-30b is important for the biology of the mammary gland and demonstrates that the deregulation of only one miRNA could affect lactation and involution.

A genetic map of bovine Chromosome (Chr) 11 (BTA11, synteny group U16) has been constructed from 330 animals belonging to 21 families, which constitute the international bovine reference panel (IBRP). This map is based on 13 polymorphic microsatellite markers, two of which were chosen in previously published maps. Three markers have been isolated from cosmids. Two of the three cosmids have been physically localized by fluorescence in situ hybridization (FISH), to anchor the genetic map on the chromosome. In addition, a biallelic polymorphism in the beta-lactoglobulin gene (LGB) has been genetically positioned relative to the microsatellite markers. The most probable order of the markers is: cen-INRA044-BM716-INRA177-(TGLA327, INRA198, INRA131)-INRA111-INRABERN169-(INRA115, INRA032)-INRA108-INRABERN162-INRA195-LGB. The total linkage group spans 126 cM, which probably corresponds to most of the chromosome length. The average intermarker distance is about 10.5 cM, allowing the potential detection of a genetic linkage with any Economic Trait Loci (ETL) of this chromosome. Seven of these markers have been previously published by Vaiman and coworkers (1994), two will be published as part of a set of markers (Eggen et al. in preparation), two are described in this paper, and two (BM716, TGLA327) were chosen from the published maps of BTA11 in order to integrate our data with existing maps. All these markers were assigned to synteny group U16 by use of a previously characterized panel of hamster/bovine somatic hybrid cell lines (Guérin et al. 1994).(ABSTRACT TRUNCATED AT 250 WORDS)

Summary One cosmid containing a microsatellite (INRA144, D9S14) was assigned to bovine synteny group U2 by somatic cell genetics and localized to bovine chromosome 9q25 by fluorescent in situ hybridization. These results permitted the assignment of one more synteny group to a bovine chromosome. There are now 22 out of 31 bovine synteny groups which are related to a chromosome. The mapping data have been entered in the BovMap database, Jouy-en-Josas, France.