F. Ciotola

Sex chromosome abnormalities and sterility in river buffalo

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.

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

Freemartinism in river buffalo: clinical and cytogenetic observations

During the last five years forty phenotypic female river buffalos with reproductive problems and two phenotypic male co-twins of females, raised in the provinces of Caserta and Salerno (southern Italy) underwent cytogenetic investigation. Of the 42 animals studied, 10 freemartins (8 females and 2 males) were found with variable percentages of male and female blood cells, the majority however showing similar percentages of both. Of the eight females, six showed normal body conformation, vagina and clitoris, while two showed some male traits (tight pelvis). The two males were apparently normal with only a reduced size of one testicle in one animal. Clinical observations performed in the internal reproductive organs of the female carriers by both rectal palpation (5 females) and direct observation after mating (3 females) revealed serious damages varying from complete lack of internal sex adducts (closed vagina) to hypoplasia of Müllerian ducts and absence (or atrophy) of ovaries. All freemartin females were sterile. To our knowledge, this is the first detailed description of freemartinism in river buffalo by combining clinical and cytogenetic analyses.

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.

Increased SCE levels in Mediterranean Italian buffaloes affected by limb malformation (transversal hemimelia)

In recent years some buffalo farms in Campania have reported the birth of calves with limb malformation, especially with transversal hemimelia. We investigated 20 Mediterranean Italian buffaloes (8 males and 12 females) from one day to six months of age, of which 10 were affected by transversal hemimelia (group 1) and 10 were healthy controls (group 2). The following clinical and radiological patterns were observed in the malformed animals: hind limbs amputated, the right amputated off the second tarsus bones and the left amputated off the proximal epiphysis metatarsus, and the right thoracic limb hypoplasic (1 female); left hind limb amputated off the proximal epiphysis metatarsus (2 females and 1 male); left hind limb amputated off the third tarsus bones (1 female); left hind limb amputated off the tibia (1 female and 1 male); left hind limb amputated off the distal epiphysis metatarsus (1 female); left hind limb amputated off the first phalanx (1 male); right hind limb amputated off the proximal epiphysis metatarsus (1 male). In their malformed limbs all the animals presented more or less developed outlines of claws. The mean rate of SCE/cell in animals with transversal hemimelia was 8.80 ± 3.19, that of the controls 6.61 ± 2.73. The difference was statistically significant (P < 0.001).

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).

Clinical, cytogenetic and molecular studies on sterile stallion and mare affected by XXY and sex reversal syndromes, respectively

Abstract Clinical, cytogenetic and molecular observations on a sterile stallion 2n = 65, XXY and a sterile mare 2n = 64, XY are reported. The XXY stallion was a pure case since all cells showed the same chromosome constitution. In the cells of mare XY, no SRY gene was found by both FISH- and molecular analyses. Both carriers show normal body conformation but were sterile because the stallion had no spermatozoa in the ejaculate, as revealed by microscope observation, and the mare showed the typical gonadal dysgenesis since both the uterus and ovaries were hypoplasic, as revealed by both rectal palpation and ultrasonic analysis. Although a mutation and / or deletion of SRY gene seems to be involved in the sex reversal, this syndrome is not yet fully understood. The possibility of other genes playing an important role in this syndrome and changes in the protein encoded by SRY are discussed.

Chromosomal expression and localization of aphidicolin-induced fragile sites in the standard karyotype of river buffalo (Bubalus bubalis)

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.

Molecular and Cytogenetic Studies in a Case of XX SRY-Negative Sex Reversal in an Arabian Horse

An 18-month-old Arabian foal characterized by a stallion-like appearance was submitted for cytogenetic and molecular genetics examinations due to abnormalities of external genitalia and the presence of ovotestis-like structures in the abdominal cavity. By RB-banding the animal showed the normal female equine karyotype (2n = 64,XX). Molecular analysis revealed the absence of the SRY and ZFY genes and the presence of ZFX, a typical female equine condition. The entire RSPO1 coding region was examined to exclude its involvement. Although a SNP was found in exon 3, it was not responsible for an amino acid substitution.

The 450-Band Resolution G- and R-Banded Standard Karyotype of the Donkey (Equus asinus, 2n = 62)

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.