A. De Giovanni

Cattle rob(1;29) originating from complex chromosome rearrangements as revealed by both banding and FISH-mapping techniques

Sixteen carriers of rob(1;29) (one of which was homozygous) from six different breeds (four Italian and two Portuguese), two heterozygous carriers of rob(26;29), three river buffaloes and two sheep were cytogenetically investigated in this study by using banding and FISH-mapping techniques (the latter only in cattle and river buffalo). Single- and dual- colour FISH were used with bovine probes containing both INRA143 (mapping proximally to BTA29) and bovine satellite (SAT) DNA SAT I, SAT III and SAT IV (mapping at the centromeric regions of cattle chromosomes). The combined use of these probes, the comparison of rob(1;29) with the dicentric rob(26;29) and with both river buffalo and sheep chromosomes (biarmed pairs) allowed us to hypothezise that rob(1;29) originated from complex chromosomal rearrangements through at least three sequential events: (a) centric fusion with the formation of a dicentric chromosome; (b) formation of a monocentric chromosome with loss of SAT I from both BTA1 and BTA29, most of SAT IV from BTA29 and, probably, some repeats of SAT III from BTA1; (c) double pericentric inversion or, more probably, a chromosome transposition of a small chromosome segment containing INRA143 from proximal p-arms to proximal q-arm of the translocated chromosome.

A case of azoospermia in a bull carrying a Y-autosome reciprocal translocation

During normal cytogenetic investigations on the Chianina cattle (BTA) breed, a normal looking young bull was found to carry an abnormal Y chromosome which was a product of a reciprocal translocation between chromosomes Y and 9. This was revealed by both CBA- and RBG-banding techniques and was clearly confirmed by FISH-mapping analysis with IDVGA50 (which paints the complete Yq arm in a normal Y), as well as with AMD1, CGA, IGF2R (mapping to BTA9q16, BTA9q22 and BTA9q27→q28, respectively) and SRY (mapping to normal BTAYq23). Analysis on sperm from four different samples revealed azoospermia in the carrier, indicating that the rcp(Y;9) induces sterility in the bull.

Characterization of a balanced reciprocal translocation, rcp(9;11)(q27;q11) in cattle

Cytogenetic analysis of a phenotypically normal young bull from Marchigiana breed revealed the presence of an abnormal karyotype. The observation of longer and smaller chromosomes than BTA1 and BTA29, respectively in all metaphases suggested the presence of a reciprocal translocation. RBG-banding confirmed this hypothesis revealing the involvement of BTA9 and BTA11. FISH analyses using cattle-specific BAC clones (474A12 and 293G09 for BTA9; 035D03 for BTA11) identified rcp(9;11)(q27;q11) in the two regions affected. Moreover analyses performed on both parents established the ‘de novo’ origin of the anomaly. Comparison with human homologue sequences (HSA6q24.3→q25.3 for BTA9q27 and HSA2q11.1→q12.1 for BTA11q11) revealed that both breakpoint regions are gene rich as up to date at least 200 genes have been localized in these regions. Thus, further analyses are required to identify the sequences disrupted by the breakpoints and to verify their consequences on rcp carrier phenotype.

A new balanced autosomal reciprocal translocation in cattle revealed by banding techniques and human-painting probes

Three hundred and twenty-two (264 males and 58 females), randomly sampled Grey Alpine cattle individuals from Northeastern Italy, were investigated cytogenetically by both conventional chromosome staining and R-banding. Two hundred and eighty-one (87%) individuals had a normal karyotype and 41 (13%) carried chromosomal aberrations such as (a) rob(1;29) in two individuals, (b) rob(26;29) in 36 individuals, (c) XX/XY-chimerism in two individuals, and (d) an abnormally long chromosome in one individual. All these aberrations except (d) have been described before. GBG-, RBG-, CBA-banding and sequential GBG/CBA- and RBG/CBA-banding techniques revealed that the abnormally long chromosome was the result of a reciprocal translocation between chromosomes 1 (q21→qter) and 5 (q11→q33), as confirmed also by chromosome painting with human chromosome 3 and 12 probes. The dam of the carrier bull carried the same translocation, while the grandam showed a normal karyotype. Since the sire of the dam was not available for study, no conclusion about the origin of the chromosome translocation could be drawn. The carrier bull was eliminated because of poor fertility. The dam had three other calves, which all were chromosomally normal. On average the dam had to be served 2.5 times (breed average was 1.2) to be in calf.

A new case of reciprocal translocation in a young bull: rcp(11;21)(q28;q12)

Routine cytogenetic investigations of the Chianina cattle (BTA) breed revealed the presence of longer and smaller chromosomes than the largest (BTA1) and smallest (BTA29) chromosomes in the cells of a young, normal-looking bull used for reproduction. Application of both RBA-banding and Ag-NOR techniques, as well as the use of the FISH technique and specific molecular markers of both BTA11 (IL1B, ASS and LGB) and BTA21 (SERPINA and D21S45) established that these two abnormal chromosomes were the product of a reciprocal translocation between BTA11 and BTA21. Both der(11) and der(21) were C-band positive and the chromosome regions affected were rcp(11;21)(q28;q12). The young bull had a normal body conformation, including external genitalia, normal levels of testosterone (as in the control) and non-detectable levels of both 17 beta-estradiol and progesterone (as in the control). The animal never showed libido in the presence of both males and females in oestrus. After slaughter at 18 months, histological evaluation revealed normal organized testes, seminiferous tubules and epididymis but with poor proliferative germ cells consisting mainly of spermatogonia, middle pachytene spermatocytes and early spermatids with late spermatids and spermatozoa being very rare.

Chromosomal characterization of three centric fusion translocations in cattle using G-, R- and C-banding and FISH technique

Abstract Five cattle, two of the Podolian breed, two Grey Alpine, and one Chianina,all of which were heterozygous carriers of three centric fusion translocations(rob-l;29, rob-4;8, rob-25;27), underwent cytogenetic investigation. The use of G-, R- and C-banding patterns, combined with the FISH technique by using both type I molecular markers and some human chromosome painting probes, allowed the precise identification of chromosomes involved in the chromosomal abnormalities,compared to previous reports. While the chromosomes involved in the well known rob (1;29) were confirmed, BTA6 (not BTA4) was involved in the second translocation. Furthermore, BTA26 and BTA29 (not BTA25 and BTA27) were involved in the third translocation. C-banding patterns confirmed the mono-centric nature of rob (1;29) and revealed the dicentric nature of both rob(6;8) and rob(26;29). The importance of these marker chromosomes in bovid chromosome nomenclatures is also discussed.

(α′)4 corrections to the N=2 supersymmetric Born–Infeld action

Abstract We consider the N =2 supersymmetric Born–Infeld action and compute one-loop divergences quantizing the theory in N =1 superspace. We find that in the presence of non constant curvature the theory is not renormalizable. The structure of the ( α ′) 4 counterterm, proportional to derivatives of the curvature, is consistent with effective action calculations from superstring theory.

A new case of rob(14;17) in cattle

Robertsonian translocations, also called centric fusions, represent the most frequent chromosome anomalies in cattle, and rob(1;29) is the most widespread. However, centric fusions involving other chromosomes have been discovered in different cattle breeds. Here we report the appearance of a new case of rob(14;17) in an Italian cattle breed more than ten years after the first and only case had been observed, and we demonstrate the independent origin of this anomaly from the previous case.

Classical and molecular cytogenetic studies in some cattle breeds

Riassunto Studi di citogenetica classica e molecolare in alcune razze bovine. Sono riportati gli studi intrapresi per caratterizzare citogeneticamente alcune anomalie cromosomiche legate a sterilità o a ipofertilità in alcuni bovini di razza Chianina, Marchigiana, Romagnola, Maremmana Grigio Alpina e Podolica. Sono state impiegate sia tecniche di citogenetica classica (bandeggio cromosomico) che molecolare (tecnica FISH) con specifici marker molecolari per indagare le seguenti anomalie cromosomiche: fusioni centriche, traslocazioni reciproche e inversioni pericentriche. Studi con il marker molecolare INRA143, che mappa nella regione pericentromerica del cromosoma 29, hanno evidenziato chiari segnali di ibridazione nella parte prossimale del braccio q di tale traslocazione, supportando l’ipotesi che questa traslocazione si sia formata per fusione centrica dei cromosomi 1 e 29 e per inversione pericentromerica del cromosoma 29. Sono stati condotti studi su alcuni animali giovani, alcuni dei quali risultati sterili o ipofertili e portatori di traslocazioni reciproche e di un inversione pericentrica al cromosoma Y