V. Barbieri

Sister Chromatid Exchanges (SCE) in the Agerolese Cattle Population

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

XX/XY Chimerism in Cattle: Clinical and Cytogenetic Studies

The freemartin condition represents the most frequent form of intersexuality found in cattle, and occasionally in other species. Freemartinism arises when vascular connections occur between placentae of developing heterosexual twin foetuses, XX/XY chimerism develops, and ultimately there is masculinisation of the female tubular reproductive tract to varying degrees. The aim of this work was to report the clinical and cytogenetic studies performed in 28 cattle co-twins, 24 of which were cytogenetically chimeric (2n = 60, XX/XY), raised in the region of Campania (southern Italy). Clinical findings of the 16 freemartin females examined varied greatly, from a more female phenotype (normal body conformation with the presence of a blind-ending vagina and primordial ovarian and uterus structures) to a nearly male phenotype (body conformations with male traits and presence of primordial prepuce, penis and testicles). The 8 freemartin males, in spite of the presence of XX cells, had a normal body conformation and external genitalia and some of them were fertile. In addition to cytogenetic diagnosis we also verified chromosome fragility by testing for chromosome aberration (CA: aneuploidy, gaps, chromatid breaks, chromosome breaks and fragments) and sister chromatid exchange (SCE). Freemartins showed a higher percentage of aneuploid cells and significant statistical differences in mean values of gaps, chromatid breaks and chromosome breaks when compared with control animals. To our knowledge, this is the first time that chromosome instability has been evaluated by analyses of CA and SCE in freemartin cattle.

Chromosome instability in Mediterranean Italian buffaloes affected by limb malformation (transversal hemimelia).

For several years, a genetic disease called transversal hemimelia (TH), also known as congenital amputation, has been spreading in Mediterranean Italian buffalo. TH is characterized by the lack of limb distal structures, normally developing proximally to the malformed limb and being amputated at different points distally. A sample of 13 animals affected by TH was examined using the chromosome aberration (CA) test to better characterize chromosome instability already emerging in a preliminary study where we found a significantly higher difference (P < 0.001) in the mean rate of sister chromatid exchange/cell (8.80 +/- 3.19) performed in 10 malformed animals, when compared with the control (6.61 +/- 2.73). The percentage of aneuploid cells was higher in animals with TH (12.76) than in control animals (7.85). Mean gaps are greater in cells of animals with TH (6.62 +/- 2.38) than those found in the control (2.86 +/- 1.01) and similar results were obtained in chromatid breaks (0.13 +/- 0.31 and 0.07 +/- 0.06, respectively), chromosome breaks (0.11 +/- 0.27 and 0.06 +/- 0.13, respectively) and CAs excluding gaps (0.24 +/- 0.47 and 0.13 +/- 0.18, respectively). All these differences are statistically highly significant (P < 0.001).

Native cattle breeds of Southern Italy: karyological profile

Abstract Italian typical products of animal origin are strictly linked to native breeds. Their protection requires control of their reproductive and productive abilities. Hence the need for karyological studies to identify subjects with chromosome abnormalities linked to hypofertility or sterility. We report the results of karyological analyses carried out from January 2008 to December 2008 on 145 cattle of native breeds (Agerolese, Cinisara, Modicana and Podolica) reared in Southern Italy so as to evaluate and characterize the presence of chromosome abnormalities in subjects with normal phenotypes. Besides the 128 karyologically normal subjects (2n=60, XY and 2n=60, XX), 17 were carriers of rob (1;29) and one male was a carrier of cellular chimerism 2n=60, XX/XY. According to our data there is a high frequency of rob (1;29) in Cinisara and Podolica breeds while in Agerolese there was only one case of rob (1;29) and none in Modicana.

An improved characterization of horse (Equus caballus, 2n=64) chromosomes by using replicating G and R banding patterns

Abstract 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.

Comparison of genome stability in two pig breeds by using the sister chromatid exchange (SCE) test

Riassunto Confronto della stabilità genomica tra due razze suine mediante il test dello scambio intercromatidico (SCE). Il test dello “scambio intercromatidico” (SCE) è stato largamente impiegato per valutare il grado di stabilità del genoma di svariate specie sottoposte all’azione di sostanze mutagene (sia naturali che di sintesi) presenti nell’ambiente. Lo scopo di questo lavoro è stato quello di confrontare la stabilità del genoma di due razze suine, la Casertana, a rischio di estinzione (FAO, 1995), originaria della Regione Campania, allevata nella maggior parte dei casi allo stato semibrado, e la Large White Italiana, altamente selezionata, allevata in modo intensivo. Per ciascuna razza sono stati esaminati 15 soggetti di età inferiore a 8 mesi, e per ogni animale sono state studiate 35 metafasi. I valori della media e della deviazione standard di SCE sono stati nella Casertana di e nella Large White Italiana di 4,38±2,40.

Chromosome fragility in Freemartin cattle

Abstract 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).