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The present study reports on the incidence of X-Y aneuploidy in the sperm population of two indigenous cattle breeds reared in Italy for beef purposes, the Podolian and Maremmana. Totally, more than 50 000 sperm nuclei from 10 subjects (5 from each breed) have been fluorescent in situ hybridization (FISH) analyzed by using Xcen- and Y-chromosome-specific painting probes. In both breeds, the fraction of Y-bearing sperm was significantly higher (P < 0.01) compared with the X-counterpart. The rates of X-Y aneuploidy were 0.180% and 0.200%, respectively, in the Podolian and Maremmana. No significant interindividual differences were found. Average frequencies of disomic and diploid sperm were 0.149% and 0.031% in the former and 0.098% and 0.102% in the latter. Significant differences (P < 0.05) were found among the XX-XY and YY-disomy classes in both breeds, while diploidy classes were uniformly represented. In the Podolian breed, disomies were more frequent than diploidies (P < 0.05), whereas in the Maremmana they showed similar frequencies. In both breeds disomies arising from errors in meiosis I (X-Y disomies) were more represented than those arising in meiosis II (XX and YY), while this difference was not detected for diploidies. The present study provides specific information on the incidence of X-Y sperm aneuploidy in two indigenous breeds of cattle, in order to establish a breed-specific 'aneuploidy data-base' that could be used as reference for genetic improvement and future monitoring of the reproductive health of the breed.

A 4-year-old male horse of Friesian breed with normal body conformation, development and libido, and showing an evident ventral penis deviation with hypospadias, underwent both cytogenetic and genetic investigation. Although the karyotype showed normal male arrangement (2n = 64,XY), one telomere of horse (ECA) chromosome 1 was shorter than both the other one and those of a normal horse (control), as revealed by CBA- and RBA-banding, and by Ag-NOR and FISH-mapping techniques using telomere PNA probes. Genetic investigation of the SRY and MAMLD1 coding sequences revealed a normal SRY sequence and a mutation in the MAMLD1 gene sequence: a homozygous change (C>A) was found, leading to the synthesis of an isoleucine, instead of a leucine. Although it is difficult to find a strict correlation between hypospadias and the genetic defects revealed by this investigation, this study is the first to be performed in a hypospadic horse using both cytogenetic and genetic investigation.

Donkey chromosomes were earlier characterized separately by C-, G- and R-banding techniques. However, direct comparisons between G- and R-banding patterns have still not been carried out in this species. The present study reports this comparison at the 450-band level by using replication G- and R-banding patterns. Two sets of synchronized lymphocyte cultures were set up to obtain early (GBA+CBA-banding) and late (RBA-banding) BrdU incorporation. Slides were stained with acridine orange and observed under a fluorescence microscope. Reverse GBA+CBA- and RBA-banded karyotypes at the 450-band level were constructed. To verify G- and R-banding patterns in some acrocentric chromosomes, sequential GBA+CBA/Ag-NORs and RBA/Ag-NORs were also performed. The results of CBA-banding patterns obtained in 12 animals from 2 breeds showed a pronounced polymorphism of heterochromatin, especially in EAS1q-prox. Ideogrammatic representations of G- and R-banded karyotypes were constructed using only one common G- and R-banding nomenclature. In the present study both G- and R-banding patterns and relative ideograms are presented as standard karyotype for this species at the 450-band level.

The present study was undertaken to investigate aneuploidy rates in the sperm populations of 2 cattle (Bos taurus) breeds by using dual color fluorescent in situ hybridization (FISH) with Xcen and Y chromosome-specific painting probes, obtained by chromosome microdissection and DOP-PCR. Frozen semen from 10 Italian Friesian and 10 Italian Brown testing bulls was used for the investigation. For each bull, more than 5,000 sperm were analyzed, for a total of 52,586 and 51,342 sperm cells for the 2 breeds, respectively. The present study revealed – in both breeds – a preponderance of the Y-bearing sperm compared to the X-bearing sperm. Within each breed, a statistically significant variation in the various classes of aneuploidy (XX, YY and XY) was found: differences were found in the Friesian breed among the 3 diploidy classes, and in the Brown breed, among the 3 disomy classes (p < 0.05) as well as among the 3 diploidy classes (p < 0.01). However, the 2 breeds did not differ significantly in the overall mean rates of X-Y aneuploidy (disomy + diploidy) which amounts to 0.162% in the Italian Friesian and 0.142% in the Italian Brown. When meiosis I (MI) and II (MII) errors were compared, statistically significant differences (p < 0.01) were found in the disomy classes and in both breeds, whereas the differences between diploidy classes were not significant. Compared to humans, a lower level of aneuploidy has been found in the domestic species analyzed so far. The present study contributes to the establishment of a baseline level of aneuploidy in the sperm populations of 2 cattle breeds which could be used for monitoring future trends of reproductive health, especially in relation to environmental changes and mutagens.

The development of a completely annotated sheep genome sequence is a key need for understanding the phylogenetic relationships and genetic diversity among the many different sheep breeds worldwide and for identifying genes controlling economically and physiologically important traits. The ovine genome sequence assembly will be crucial for developing optimized breeding programs based on highly productive, healthy sheep phenotypes that are adapted to modern breeding and production conditions. Scientists and breeders around the globe have been contributing to this goal by generating genomic and cDNA libraries, performing genome-wide and trait-associated analyses of polymorphism, expression analysis, genome sequencing, and by developing virtual and physical comparative maps. The International Sheep Genomics Consortium (ISGC), an informal network of sheep genomics researchers, is playing a major role in coordinating many of these activities. In addition to serving as an essential tool for monitoring chromosome abnormalities in specific sheep populations, ovine molecular cytogenetics provides physical anchors which link and order genome regions, such as sequence contigs, genes and polymorphic DNA markers to ovine chromosomes. Likewise, molecular cytogenetics can contribute to the process of defining evolutionary breakpoints between related species. The selective expansion of the sheep cytogenetic map, using loci to connect maps and identify chromosome bands, can substantially contribute to improving the quality of the annotated sheep genome sequence and will also accelerate its assembly. Furthermore, identifying major morphological chromosome anomalies and micro-rearrangements, such as gene duplications or deletions, that might occur between different sheep breeds and other Ovis species will also be important to understand the diversity of sheep chromosome structure and its implications for cross-breeding. To date, 566 loci have been assigned to specific chromosome regions in sheep and the new cytogenetic map is presented as part of this review. This review will also summarize the current cytogenomic status of the sheep genome, describe current activities in the sheep cytogenomics research sector, and will discuss the cytogenomics data in context with other major sheep genomics projects.

Multi-copied gene families are prevalent in mammalian genomes, especially within the Y chromosome. Testis specific protein Y-encoded (TSPY) is present in variable copy number in many mammalian species. Previous studies have estimated that TSPY ranges from 50–200 copies in cattle. To examine TSPY localization on the Y chromosome we employed fluorescence in situ hybridization (FISH) and fiber-FISH. The results show a strong signal on the short arm of the Y chromosome (Yp). To investigate TSPY copy number we used relative real-time polymerase chain reaction (PCR) to analyze the DNA of 14 different cattle breeds. Variation both within and between breeds was observed. All breeds show significant variation in TSPY copy number among individual members. Brown Swiss (161 copies, CI = 133–195) had higher average levels of TSPY and Western Fjord Cattle (63 copies, CI = 45–86) had lower levels than some breeds. Overall, however, most breeds had a similar average TSPY copy number. The pooled average was 94 copies (CI = 88–100). The significance of the TSPY array remains uncertain, but as the function of TSPY is unraveled the purpose of the array may become clearer.

Few goat genome analysis projects have been developed in the last 10 years. The aim of this review was to compile and update all available cytogenetic mapping data, according to the last goat chromosome nomenclature, as well as human and cattle whole genome sequences. In particular, human regions homologous to most of the FISH-mapped microsatellites were identified in silico. This new goat cytogenetic map made it possible to refine delineation of conserved segments relative to the human and cattle genomic sequence. These improvements did not lead to detection of major new rearrangements within ruminants but confirmed the good conservation of synteny and the numerous intrachromosomal rearrangements observed between goats and humans.

WWOX (WW domain-containing oxidoreductase) is the gene mapping at FRA16D HSA16q23.1, the second most active common fragile site in the human genome. In this study we characterized at a detailed molecular level WWOX in the bovine genome. First, we sequenced cDNA from various tissues and obtained evidence in support of a 9-exon structure for the gene, similar to the human gene. Then, we recovered BACs using exon tags and annotated the gene to a >1-Mb genomic region of BTA18 using the Btau 4.0 genome assembly as a reference, thus resolving an issue related to exon 9, which is not included in the genomic annotation of the gene in the Entrez database. Finally, BACs spanning WWOX were used as FISH probes to obtain comparative mapping of the gene in Bos taurus, Bubalus bubalis, Ovis aries and Capra hircus to BTA18q12.1, BBU18q13, OAR14q12.1 and CHI18q12.1, respectively. Our data show that the chromosomal location of WWOX is conserved between man and 4 major domesticated species. Moreover, the annotation of the bovine gene also suggests a highly conserved genomic arrangement, including number and size of introns.

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.

Thirteen male river buffaloes, 119 females with reproductive problems (which had reached reproductive age but had failed to become pregnant in the presence of bulls) and two male co-twins underwent both clinical and cytogenetic investigation. Clinical analyses performed by veterinary practitioners revealed normal body conformation and external genitalia for most females. However, some subjects showed some slight male traits such as large base horn circumference, prominent withers and tight pelvis. Rectal palpation revealed damage to internal sex adducts varying between atrophy of Mullerian ducts to complete lack of internal sex adducts (with closed vagina). All bulls had normal karyotypes at high resolution banding, while 25 animals (23 females and 2 male co-twins) (20.7%) with reproductive problems were found to carry the following sex chromosome abnormalities: X monosomy (2 females); X trisomy (1 female); sex reversal syndrome (2 females); and free-martinism (18 females and 2 males). All female carriers were sterile. Copyright (C) 2008 S. Karger AG, Basel.

The present study reports on the chromosomal expression and localization of aphidicolin-induced fragile sites in the standard karyotype of river buffalo (Bubalus bubalis, 2n = 50) with the aim of establishing a ‘fragile site map’ of the species. Totally, 400 aphidicolin-induced breakages were analyzed from eight young and clinically healthy animals, four males and four females; these breakages were localized in 106 RBG-negative chromosome bands or at the band-interband regions. The number of breakages per chromosome did not vary statistically ‘among’ the animals investigated but the differences among individual chromosomes were highly significant thus indicating that the chromosomal distribution of the breakages is not random and appears only partially related to chromosome length. Fragile sites were statistically determined as those chromosomal bands showing three or more breakages. In the river buffalo karyotype, 51 fragile sites were detected and localized on the standardized ideogram of the species. The most fragile bands were as follows: 9q213 with 24 breakages out of 400; 19q21 with 16, 17q21 and inacXq24 with 15, 15q23 with 13 and 13q23 with 12 breaks, respectively. Previous gene mapping analysis in this species has revealed that the closest loci to these fragile sites contain genes such as RASA1 and CAST (9q214), NPR3 and C9 (19q19), PLP and BTK (Xq24-q25), OarCP09 (15q24), and EDNRB (13q22) whose mutations are responsible for severe phenotypic malformations and immunodeficiency in humans as well as in mice and meat quality in pigs. Further cytogenetic and molecular studies are needed to fully exploit the biological significance of the fragile sites in karyotype evolution of domestic animals and their relationships with productive and reproductive efficiency of livestock.

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.

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Milk production performance of dairy buffaloes from 9 herds was evaluated. There were a total of 1,858 305D milk production records containing 13,219 milk test records from 1997 to 2006 available for evaluation. Records were analyzed with general linear model to determine the effect of season, parity and age at calving on standard 305D milk yield. Parity, season of calving and age at calving affected milk yield significantly. Average 305D milk production increased significantly from 864 kg in 1997 to 1244 kg in 2006. Genetic evaluation of milk production traits was also done using the same data set. The model for analysis is a multi-trait full animal model. Only the first three lactations are included in the analysis. The first lactation is divided into three stages namely, 100D, 200D, 300D each being considered as three separate traits. The resulting values from the three traits are combined into one to get the first lactation estimated breeding values (EBV). The genetic correlations between traits were all positive ranging from 0.78 to 0.94 between 100D and 303D of the lactation and between the 2nd and third lactation respectively. Estimates of heritabilities used in the analysis were 0.36, 0.39, 0.30, 0.32, and 0.33, for 100D, 200D, 300D, 2nd lactation and 3rd lactation respectively. The average EBVs of cows were plotted against birth year. The trend was positive with 4 kg and 8.4 kg increase per birth year for the 1st and both the 2nd and 3rd lactation respectively. This positive trend is consistent and may be responsible for the increase in milk production performance of cows. Apparently, selection of replacement animals based on milk production performance of dams and use of imported semen from proven bulls was effective before EBV information on sires and dams are available in the Philippines. The use of EBVs in selection would increase the rate of genetic improvement in dairy buffalo population in the Philippines.

The present study provides specific cytogenetic information on prometaphase chromosomes of the alpaca (Lama pacos, fam. Camelidae, 2n = 74) that forms a basis for future work on karyotype standardization and gene mapping of the species, as well as for comparative studies and future genetic improvement programs within the family Camelidae. Based on the centromeric index (CI) measurements, alpaca chromosomes have been classified into four groups: group A, subtelocentrics, from pair 1 to 10; group B, telocentrics, from pair 11 to 20; group C, submetacentrics, from pair 21 to 29; group D, metacentrics, from pair 30 to 36 plus sex chromosomes. For each chromosome pair, the following data are provided: relative chromosome length, centromeric index, conventional Giemsa staining, sequential QFQ/C-banding, GTG- and RBG-banding patterns with corresponding ideograms, RBA-banding and sequential RBA/silver staining for NOR localization. The overall number of RBG-bands revealed was 391. Nucleolus organizer-bearing chromosomes were identified as pairs 6, 28, 31, 32, 33 and 34. Comparative ZOO-FISH analysis with camel (Camelus dromedarius) X and Y painting probes was also carried out to validate X-Y chromosome identification of alpaca and to confirm close homologies between the sex chromosomes of these two species.

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.

Fifty-one phenotypically normal Maronesa cattle (28 males and 23 females) from North-Portugal were studied to ascertain the frequency of SCEs in normal karyotypes and in karyotypes carrying rob (1;29). In the 1852 examined cells, the mean value of SCEs was 7.1 +/- 3.6. In the 841 cells from 23 normal karyotype animals the mean value of SCEs was 6.6 +/- 3.6; in the 611 cells from 17 heterozygous carriers of rob (1;29) the mean value of SCEs was 7.1 +/- 3.3; in 400 cells from 11 homozygous carriers the mean value of SCEs was 8.1 +/- 3.8. All these differences were highly significant (P < 0.001). No statistical differences were found between the mean values of SCEs in male (7.0 +/- 3.7) and female (7.1 +/- 3.5) cells in the total sampling. However, in 280 cells from two pairs of heterosexual twins, we found that the mean value of SCEs in female cells (7.9 +/- 3.0) was significantly higher than that in male cells (5.7 +/- 3.1).

The major histocompatibility complex (MHC) in humans is a polymorphic assemblage of over 70 genes which play key roles in the regulation of the immune response (TROWSDALE et al. 1991). The bovine MHC (bovine lymphocyte antigen, BoLA) was assigned to a rather broad region of cattle chromosome 23 (ql3-23) by sequential Q-banding and isotopic in situ hybridization (FRIES et al. 1986; HEDIGER et al. 1991). In the present study, we use sequential RBA-banding and fluorescent in situ hybridization

Peripheral blood lymphocytes were cultured and treated for early- and late-BrdU incorporation to perform replicating G- and R-banding patterns, respectively. Slides were treated for GBG-, RBA- and RBG-banding techniques. Improved banded karyotypes at early- (350 bands) and pro-metaphase (500 bands) stage were performed and GBG- and RBA-banded prometaphase karyotypes were presented for the first time on this species. All chromosomes, including the small acrocentrics, show clear and distinguishable G- and R-banding patterns. Chromosome identification followed the latest chromosome standard nomenclature (ISCNH 1997). This study is also our contribution to further standard karyotype attempts at the prometaphase stage.

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.

This study was undertaken to provide cytogenetic information about onset and sequence of RBA-band replication on the inactive X-chromosomes of cattle, river buffalo and goat. Blood cultures were synchronized overnight with thymidine after 48 hours of growth. The cell block was released with fresh medium and the cells allowed to grow in the presence of BrdU and H33258 for 1, 2, 4, 6, 8, 10, 12 and 14 hours, including 20 minutes colcemide. Results show that: (a) the onset of RBA-banding replication was 12 hours before mitosis in cattle and river buffalo, 14 hours in the goat; (b) the replication process was still ‘on’ in cattle and river buffalo one hour before mitosis, whereas it was ‘off’ in the goat; consequently the length of the G2 phase was less than one hour in cattle and river buffalo and one hour or slightly longer in the goat; (c) the first band undergoing replication was identified as band Xq31 in cattle, homologous to band Xq34-36 in river buffalo and Xq24 in the goat; (d) the second replicating band was the Xp22 in cattle, homologous to band Xq21 in river buffalo and Xq34 in the goat, respectively; (e) the sequence of RBA-band replication was quite similar between cattle and river buffalo, but reversed in the goat, due to the wide chromosomal rearrangements which differentiated the X-chromosome of Caprinae from that of Bovinae.

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).

L. Iannuzzi, G. P. Di Meo , H. Hayes 2 , A. Perucatti, D. Incarnato , M. Gautier 2 & A. Eggen 2 1 National Research Council (CNR), IABBAM, Via Argine 1085, 80147 Naples, Italy; Tel: +39-081-5964977; Fax: +39-081-5965291; E-mail: L.Iannuzzi@iabbam.na.cnr.it ; 2 Research Center, INRA, Laboratory of Genetics and Cytogenetics, Department of Animal Genetics, 78352 Jouy-en-Josa,s, France *Technical assistance and microscope image processing

The aim of the present study was to verify chromosome fragility in freemartin cattle using chromosome aberration (CA) and sister chromatid exchange (SCE) tests. A total of eighteen co-twins were investigated. Fourteen animals were identified as cytogenetically chimeric (2n=60, XX/XY) while 4 were classified as normal. Freemartin cattle showed a higher percentage of aneuploid cells (18.64%) and highly significant statistical differences (P < 0.001) in mean values of gaps (4.53 ± 2.05), chromatid breaks (0.26 ± 0.51), and significant statistical differences (P < 0.005) in mean values of chromosome breaks (0.12 ± 0.43) when compared to 10 control animals from single births (aneuploid cells, 11.20%; gaps, 2.01 ± 1.42; chromatid breaks, 0.05 ± 0.22; chromosome breaks, 0.02 ± 0.14).

A series of 31 marker genes (one per chromosome) were localized precisely to both Q- and R-banded bovine chromosomes by fluorescence in situ hybridization (FISH), as a contribution to the revised chromosome nomenclature of the three major domestic bovidae (cattle, sheep and goat). All marker genes except one (LDHA) are taken from the Texas Nomenclature of the cattle karyotype published in 1996. Homologous probes for each marker gene were obtained by screening a bovine BAC library by PCR with specific primer pairs. After labeling with biotin, each probe preparation was divided into two fractions and hybridized to bovine chromosomes identified either by Q or R banding. Clear signals and good quality band patterns were observed in all cases. Results of the two series of hybridizations are totally concordant both for Q and R band chromosome numbering and precise band localization. This work permits an unambiguous correlation between the Q/G- and R-banded 31 bovine chromosomes, including chromosomes 25, 27 and 29 which remained unresolved in the Texas Nomenclature (1996). Hybridization of the chromosome 29 marker gene to metaphase spreads from a 1;29 Robertsonian translocation bull carrier showed a positive signal on the short arm of this rearranged chromosome, confirming that the numbering of this long-known translocation in cattle is correct when referring to the Texas Nomenclature (1996). Taking into account that cattle, goat and sheep have very similar banded karyotypes, the data presented here will help to establish a definite and complete reference chromosome nomenclature for these species.

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

Cytogenetic investigations performed in eight Portuguese cattle breeds revealed the presence of rob(1;29) in both heterozygous and homozygous conditions in all, and five breeds, respectively, with variable percentages of carriers as follows: 41.0% in Arouquesa, 69.9% in Barrosa, 39.4% in Maronesa, 2.8% in Mirandesa, 8.5% in Marinhoa, 1.8% in Mertolenga, 21.3% in Raca Brava and 21.5% in Alentejana. CBA- and RBA-banding were performed to ascertain the chromosomes involved in the chromosome abnormality. A total of 1,626 animals were investigated. Reproductive parameters (number of calves per 100 cows) were higher in Mirandesa (80%) when compared with both Maronesa (75%) and Barrosa (70%) breeds, underlining that rob(1;29) reduces fertility in the carriers.

Commercially available human chromosome (HSA) painting probes were hybridized on river buffalo (Bubalus bubalis, 2n = 50) chromosomes by using FISH and R-banding techniques. Clear hybridization FITC-signals revealed extensive conservation of human chromosome regions in this species and demonstrated that human chromosome probes primarily paint euchromatic regions (R-bands). The present results are discussed in the light of previous gene mapping data obtained in river buffalo and ZOO-FISH data in cattle, and in relation to the standard bovine chromosome nomenclatures. In particular, HSA 8, HSA 10, HSA 11, and HSA 16+7 paint, respectively, BBU 1p, BBU 4p, BBU 5p, and BBU 24, which are homoeologous, respectively, to cattle chromosomes 25, 28, 29 and 27. Thus, these river buffalo chromosome arms can serve as markers to resolve discrepancies in the nomenclature of cattle and related species.

Summary Constitutive heterochromatin (HC = C-banding) distribution was studied in pig (Sus 5crofa) chromosomes from 20 animals belonging to Cinta Senese and Calabrese breeds raised in southern Italy. The use of CBG-banding, sequential GBG/CBA-banding and sequential GBGA/g- NOR/CBA-banding techniques allowed more detailed characterization of C-banding patterns in pig chromosomes (SSC). The following features were noticed: (a) all autosomes and the X-chromosome showed centromeric C-positive bands; (b) the entire q-arm and proximal part of the p-arm y chromosome were C-positive: (c) clear interstitial C-positive bands were noticed in SSC1q17, SSC3p14 and SSC16q21; (d) the nucleolus organizer (NO) chromosome 10 showed two distinct HC-blocks very far apart in both arms with large, polymorphic (different size) NORs between the chromosome pair, while NO-chromosome 8 showed only one C-positive band (the smallest) in the q-arms; (e) C-band polymorphism was observed between and within chromosome pairs also in relat...

Sheep (OAR), goat (CHI) and cattle (BTA) R-banded chromosome preparations, obtained from synchronized cell cultures, were used to FISH-map leptin (LEP) and solute carrier family 26 member 2 (SLC26A2) genes on single chromosome bands. LEP maps on OAR4q32 and CHI4q32, being the first assignment of this gene to these two species. SLC26A2 maps on BTA7q24, OAR5q24 and CHI7q24. This gene, too, was assigned for the fist time to both sheep and goat chromosomes, while it was more precisely localized on a single chromosome band in cattle. Improved cytogenetic maps of BTA4/OAR4/CHI4 were constructed and compared with HSA7 revealing five main conserved segments and complex chromosome rearrangements, including a centromere repositioning, differentiating HSA7 and BTA4/OAR4/CHI4.

Two genomic clones of the villin (VIL) gene were independently hybridized on river buffalo (Bubalus bubalis, BBU), sheep (Ovis aries, OAR) and goat (Capra hircus, CHI) chromosomes by using sequential fluorescence in situ hybridization (FISH) and R-banding (RBP- and RBA-banding). Clear hybridization signals revealed that VIL is located in BBU 2q33, OAR 2q33 and CHI 2q33. These chromosomes and chromosome bands are believed to be homologous and the VIL locus is the same as that previously found on cattle chromosome 2q43. VIL localization in these three species allows us tentatively to assign all cattle U17 to BBU and CHI 2q and to extend the physical map to OAR 2q.

Four bovine BAC clones (0494F01, 0069D07, 0060B06, and 0306A12) containing MUC1, as confirmed by mapping MUC1 on a RH3000 radiation hybrid panel, were hybridised on R-banded chromosomes of cattle (BTA), river buffalo (BBU), sheep (OAR) and goat (CHI). MUC1 was FISH-mapped on BTA3q13, BBU6q13, OAR1p13 and CHI3q13 and both chromosomes and chromosome bands were homoeologous confirming the high degree of chromosome homoeologies among bovids and adding more information on the pericentromeric regions of these species’ chromosomes. Indeed, MUC1 was more precisely assigned to BTA3 and assigned for the first time to BBU6, OAR1p and CHI3. Moreover, detailed and improved cytogenetic maps of BTA3, CHI3, OAR1p and BBU6 are shown and compared with HSA1.

F. Ciotola1, V. Peretti1,∗, G.P. Di Meo2, A. Perucatti2, L. Iannuzzi2 and V. Barbieri1 1Department of Animal Production and Food Inspection, Section B. Ferrara, Faculty of Veterinary Medicine, University of Naples Federico II, 80137 Naples, Italy; 2National Research Council (CNR), ISPAAM, Laboratory of Animal Cytogenetics and Gene Mapping, Naples, Italy ∗Correspondence: E-mail: vincenzo.peretti@unina.it

A mixture of five genomic clones spanning the alpha-S2 casein gene (CSN1S2) were mapped to river buffalo (Bubalus bubalis L.) and cattle (Bos taurus L.) chromosomes by fluorescence in situ hybridization (FISH) and R-banding. Clear probe hybridization signals were detected on river buffalo chromosome 7q, band 32, and the homologous cattle chromosome. These mapping data allow the indirect assignment of the entire cattle U15 syntenic group to river buffalo chromosome 7. The assignment of U15 to river buffalo chromosome 7 is discussed in the light of chromosomal nomenclature discrepancies involving the homologous cattle chromosome.

High-resolution chromosomal fluorescence in situ hybridization (FISH) and R-banding allowed the chromosomal localization of the β-defensin gene cluster (DEFB@) to chromosome band 1p12 in the river buffalo (Bubalus bubalis, 2n = 50) and to band 24q13 in sheep (Ovis aries, 2n = 54), according to standard nomenclatures. The localizations permitted the tentative assignment of the entire bovine syntenic group U25 to these chromosomes. A FISH mapping control on cattle chromosomes confirmed the localization of DEFB@ in the homoeologous chromosome and chromosome band. Comparisons were made between river buffalo chromosome 1p and the homoeologous cattle chromosome on standard karyotypes; the results are discussed in light of gene assignments, extensive chromosome band conservation among the Bovidae, and inconsistencies in domestic cattle chromosome nomenclatures.

SUMMARYConstitutive heterochromatin (HC) distribution among river buffalo (Bubalus bubalis L., 2n = 50) chromosomes was analyzed by using both the CBA- technique and GBA + CBA technique. CBA-banding revealed the presence of HC in the centromeric regions of all the chromosomes of the 15 animals we investigated. The five biarmed pairs showed very small HC-blocks, the remaining autosomes and the X- chromosomes showed pronounced HC-blocks with a high degree of HC-variation among them. The Y-chromosome showed a variable C-banding pattern on the basis of the different degree of chromosomal denaturation. A C-positive and heteromorphic band was also found at the telomere of chromosome 4p. The simultaneous visualization of fluorescent C and G-bands (GBA + CBA technique) in 10 animals allowed us to study the HC-distribution among and within chromosome pairs. Chromosomes showing HC-polymorphism between chromosome pairs were number 6 (6/10 animals), 11 (5/10 animals), 19 (5/10 animals) and 24 (7/10 animals).

G- and R-banded chromosomes of 14 Gentile di Puglia sheep (Ovis aries L., 2n = 54) from southern Italy were compared at the 450-band level (ISCNDA, 1989). GTG-, GBG-, RBG-, and RBA-banding techniques were employed on slides obtained from blood cell cultures that had incorporated BrdU either early or late in the replication cycle. The banding comparison improved the characterization of sheep chromosomes and allowed the construction of G- and R-banded idiograms using only one common banding nomenclature. Detailed descriptions of some disputed chromosomes are reported.

Summary Bovine BAC clones containing the 31 genes, referred to as the Texas markers used earlier to definitively assign the 31 bovine syntenic groups (U) to cattle chromosomes, were mapped by fluorescent in situ hybridization to sheep and goat R-banded chromosomes according to ISCNDB2000. All 31 markers were localized on homoeologous chromosomes and chromosome bands of the two species in agreement with previous localizations obtained both in cattle and river buffalo, definitively confirming chromosome homoeologies between Caprinae and Bovinae. In addition, we have extended physical maps of sheep and goat as 11 genes (HSD3B1, INHBA, CSN10, IGF2R, PIGR, MAP1B, DSC1, ELN, TNFRSF6, CGN1, IGF2) and 14 genes (SOD1, HSD3B1, CSN10, IGF2R, RB1, TG, PIGR, MAP1B, IGH@, LTF, DSC1, TNFRSF6, CGN1, IGF2) were assigned for the first time to goat and sheep chromosomes, respectively.