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Fifty river buffalo (Bubalus bubalis, 2n=50) cows reared in two different provinces of Campania (southern Italy) underwent cytogenetic investigations to ascertain possible differences in their chromosome stability. One group (Caserta province) was under legal sequestration due to the presence in the milk mass of higher mean values of dioxins [21.79 pg/g of fat as sum of polychloro-dibenzo-dioxins (PCDDs), polychloro-dibenzo-furans (PCDFs) and dioxinlike polychlorobiphenyls (DL-PCBs)] than both those permitted (6.0 pg/g of fat asWHO-TEQ) and those (1.3 pg/g of fat as WHO-TEQ) observed in the control group raised in Salerno province. Two types of peripheral blood cell cultures were performed: without (normal cultures for the chromosome abnormality (CA) test: chromatid breaks, chromosome breaks, fragments) and with the addition of BrdU for the sister chromatid exchange (SCE) test). The CA test revealed a significantly (P

Cytogenetic maps are useful tools for several applications, such as the physical anchoring of linkage and RH maps or genome sequence contigs to specific chromosome regions or the analysis of chromosome rearrangements. Recently, a detailed RH map was reported in OAR1. In the present study, we selected 38 markers equally distributed in this RH map for identification of ovine genomic DNA clones within the ovine BAC library CHORI-243 using the virtual sheep genome browser and performed FISH mapping for both comparison of OAR1 and homoeologous chromosomes BBU1q-BBU6 and BTA1-BTA3 and considerably extending the cytogenetic maps of the involved species-specific chromosomes. Comparison of the resulting maps with human-identified homology with HSA2q, HSA3, HSA21 and HSA1q reveals complex chromosome rearrangements differentiating human and bovid chromosomes. In addition, we identified 2 new small human segments from HSA2q and HSA3q conserved in the telomeric regions of OAR1p and homoeologous chromosome regions of BTA3 and BBU6, and OAR1q, respectively. Evaluation of the present OAR1 cytogenetic map and the OAR1 RH map supports previous RH assignments with 2 main exceptions. The 2 loci BMS4011 and CL638002 occupy inverted positions in these 2 maps.

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.

International audience; 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.

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.

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.

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International audience; 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.

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Although several studies have been undertaken on river buffalo chromosomes,the clinical cytogenetics is relatively recent in this important bovid. Indeed,only when speci¢c research programs on females river buffaloes with reproductive disturbances and a collaborative work between cytogeneticists and veterinary practioners were undertaken,significant results will be obtained. In this study we summarize the results of a cytogenetic investigation performed during the last three years on females with reproductive problems and two males free-martin. Peripheral blood cultures were untreated and treated with BrdU and H-33258 six hours before harvesting to get normal and R-banded preparations,respectively. Slides were treated for CBA and R-banding techniques. Some specific cases were also treated for FISH-technique. Upon 59 investigated animals,of which 57 were females with reproductive problems and 2 were males free-martin, 14 (24%) were carriers of sex chromosome abnormalities. The following abnormalities were found in the females: (a) sex reversal syndrome (2n =50,XY) in two animals; (b) X-monosomy (2n =49,X0) in one animal; (c) X-trisomy (2n =51,XXX) in one animal; (d) free-martinism (2n =50,XY/XX with different frequencies of female and male cells among the animals) in 6 females; (e) a pronounced C-band polymorphism in the X-chromosomes of two females. Both rectal palpation in all females and direct observation of some reproductive organs (after the animal’s mating) revealed evident abnormalities in the internal reproductive organs.

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