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.

Comparative FISH mapping of river buffalo (Bubalus bubalis, BBU), sheep (Ovis aries, OAR), and cattle (Bos taurus, BTA)

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.

During the past four years several livestock farms (sheep, cattle and river buffalo) in the provinces of Naples and Caserta (southern Italy) have been unable to sell their milk and other dairy products due to the levels of dioxins (17 different types) present in the milk mass exceeding the value permitted [3 pg/g of fat, as human WHO 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD or dioxin) equivalent]. While some farms, especially those showing relatively low levels of dioxins, have managed to reduce the dioxins in the milk below the permitted threshold by changing the diet, many, especially sheep farms, have failed to do so. Indeed, about 12 000 head of cattle, river buffaloes and sheep have so far been culled. In the present study, 34 and 42 sheep from two herds raised in the province of Naples (Acerra municipality) and where high levels of dioxins (50.65 and 39.51 pg/g of fat, respectively) were found in the milk mass, were cytogenetically investigated and compared with 20 sheep (control) raised 80 km away from the exposed area. Increases of both chromosome abnormalities (gap, chromosome and chromatid breaks) (17 and 8 times higher in the two exposed herds, respectively) and sister chromatid exchanges (SCEs) were found in both herds when compared with the control, and the differences were highly significant (P < 0.001). No statistical differences were found when comparing the frequencies of aneuploid cells of exposed animals (16.4 and 17.8%) and control (17.9%). Furthermore, high levels of mortality and abnormal foetuses were recorded in one of the two farms when compared with the control.