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The present study reports on the frequency of X-Y aneuploidy in the sperm population of two minor cattle breeds reared in Italy, namely Modicana and Agerolese, which are listed in the "Anagraphic Register of autochthonous cattle populations with limited distribution". More than 50 000 sperm nuclei from 11 subjects (5 and 6, respectively for each breed) have been analyzed by the fluorescent in situ hybridization with the Xcen and Y-chromosome specific painting probes. The fraction of X- and Y-bearing sperm was close to the 1:1 ratio in the Modicana breed, whereas in the Agerolese the Y-fraction was significantly higher (P < 0.002) compared to the X-counterpart. The mean rates of X-Y aneuploidy were 0.510 and 0.466%, respectively, in the two breeds; no significant differences were found among individual bulls within each breed. Average frequencies of disomic and diploid sperm were 0.425 and 0.085% in the former and 0.380 and 0.086% in the latter. In both breeds, (a) disomy was significantly more frequent than diploidy (P < 0.01), (b) YY disomy was significantly (P < 0.001) more frequent than XY or XX; (c) MI errors (XY disomy) were significantly (P < 0.01) less represented than MII (XX + YY disomy). Compared to the dairy (Italian Friesian and Brown) and meat (Podolian and Maremmana) breeds previously analyzed, the "minor" breeds investigated in the present study showed a significantly (P < 0.002) higher rate of X-Y aneuploidy (0.486 vs. 0.159 and 0.190%, respectively). Considering all the breeds analyzed -so far- and assuming no significant interchromosomal effect, the baseline level of aneuploidy in the sperm population of the species Bos taurus was estimated as 5.19%. Establishing the baseline level of aneuploidy in the sperm population of the various livestock species/breeds engaged in animal production could reveal useful for monitoring future trends of their reproductive health, especially in relation to management errors and/or environmental hazards., (Copyright © 2012 Elsevier Inc. All rights reserved.)

In vitro-matured metaphase II (MII) oocytes with corresponding first polar bodies (I pb) from two indigenous cattle (Bos taurus) breeds have been investigated to provide specific data upon the incidence of aneuploidy. A total of 165 and 140 in vitro-matured MII oocytes of the Podolian (PO) and Maremmana (MA) breeds, respectively, were analyzed by fluorescence in situ hybridization using Xcen and five chromosome-specific painting probes. Oocytes with unreduced chromosome number were 13.3% and 6.4% in the two breeds, respectively, averaging 10.2%. In the PO, out of 100 MII oocytes + I pb analyzed, two oocytes were nullisomic for chromosome 5 (2.0%) and one disomic for the same chromosome (1.0%). In the MA, out of 100 MII oocytes + I pb, one oocyte was found nullisomic for chromosome 5 (1.0%) and one was disomic for the X chromosome (1.0%). Out of 200 MII oocytes + I pb, the mean rate of aneuploidy (nullisomy + disomy) for the two chromosomes scored was 2.5%, of which 1.5% was due to nullisomy and 1.0% due to disomy. By averaging these data with those previously reported on dairy cattle, the overall incidence of aneuploidy in cattle, as a species, was 2.25%, of which 1.25% was due to nullisomy and 1.0% due to disomy. The results so far achieved indicate similar rates of aneuploidy among the four cattle breeds investigated. Interspecific comparison between cattle (Xcen-5 probes) and pig (Sus scrofa domestica) (1-10 probes) also reveal similar rates. Further studies are needed that use more probes to investigate the interchromosomal effect. Establishing a baseline level of aneuploidy for each species/breed could also be useful for improving the in vitro production of embryos destined to the embryo transfer industry as well as for monitoring future trends of the reproductive health of domestic animals in relation to management errors and/or environmental hazards., (Copyright © 2012 Elsevier Inc. All rights reserved.)

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., (Copyright © 2011 Elsevier Inc. All rights reserved.)

The current study was undertaken to investigate the aneuploidy rates in in vitro-matured meiosis II (MII) oocytes and corresponding first polar bodies in two dairy cattle (Bos taurus) breeds by using dual-color fluorescent in situ hybridization (FISH). A total of 159 and 144 in vitro-matured MII oocytes of the Italian Friesian and Italian Brown breeds, respectively, were obtained according to the standard methods and analyzed by FISH using "Xcen" and "5" chromosome-specific painting probes, produced by chromosome microdissection and Degenerate Oligonucleotide Primer- Polymerase Chain Reaction (DOP-PCR). Oocytes with unreduced chromosome number were 10.1% and 16.7% in the two breeds, respectively. To avoid bias due to possible artifacts, the aneuploidy rates were determined by analyzing only oocytes with the corresponding polar bodies. In the Italian Friesian, 100 of 143 (69.9%) secondary MII oocytes showed clear MII plates with corresponding first polar bodies and were scored for aneuploidy detection; one oocyte was "nullisomic" for chromosome X (1.0%) and one "disomic" for chromosome 5 (1.0%). In the Italian Brown, 100 of 120 (83.3%) MII oocytes with corresponding first polar bodies were analyzed; one oocyte was nullisomic (1.0%) and one was disomic (1.0%), both for chromosome 5. Totally, 303 oocytes were analyzed, 40 of which showed an unreduced chromosome complement (13.2%); of 200 MII oocytes with the corresponding first polar bodies, the aneuploidy rate (nullisomy+disomy) for the two chromosomes scored was 2%. Assuming that each chromosome is equally involved in aneuploidy, it results that in cattle oocytes matured in vitro, at least 30% of the oocytes (1x30 haploid chromosomes) should be aneuploid. Premature separation of sister chromatids (PSSC) was also observed in 2% of the oocytes in the Italian Friesian breed involving chromosome 5 and in 1% of the Italian Brown breed involving the X chromosome. Estimation of the "baseline" level of aneuploidy in the in vitro-matured oocytes of the various domestic animal species and breeds is, to our opinion, a useful reference for improving the in vitro production of embryos as well as for monitoring future trends of the reproductive health of the species/breeds engaged in zootechnical productions, especially in relation to management errors and environmental hazards., (Copyright 2010 Elsevier Inc. All rights reserved.)

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., ((c) 2009 S. Karger AG, Basel.)

South American camelids have been poorly genetically investigated and little information is available in llamas (Lama glama) regarding the diversity of the caseins at the protein and gene level. Exon skipping and duplication events previously reported in the αS1-casein gene (CSN1S1) led us to investigate the genetic variability at this locus. Seventy-two positive clones for the αS1-casein transcripts were analyzed and randomly sequenced. The comparative analysis of the sequences revealed 2 transitions, c.366A>G and c.690T>C, at the 10th nucleotide of exon 12 and 94 bp of exon 19, respectively. These SNP are responsible for 2 amino acid changes, Ile→Val in position 86 and Tyr→His in position 194 of the mature protein. Both polymorphisms clarify the genetic events behind the protein variants A and B. This result was confirmed by isoelectric focusing analysis of llama milk samples. Quick methods based on PCR-RFLP and allele-specific PCR were set up for allelic discrimination in a population of 128 animals. Based on genotyping results, 4 haplotypes were observed and the estimated frequencies indicated B as the most common haplotype (0.629) in the investigated population. These data add knowledge to the genetic variability of a species little investigated, and open opportunity for new investigation in the field of milk protein for South American camelids, including the possibility, in the future, to select alleles with favorable characteristics. [ABSTRACT FROM AUTHOR]