Sperm nuclei analysis of 1/29 Robertsonian translocation carrier bulls using fluorescence in situ hybridization.

In 1964, Gustavsson and Rockborn first described the 1/29 Robertsonian translocation in cattle. Since then, several studies have demonstrated the negative effect of this particular chromosomal rearrangement on the fertility of carrier animals. During the last decade, meiotic segregation patterns have been studied on human males carrying balanced translocations using FISH on decondensed sperm nuclei. In this work, we have applied the 'Sperm-FISH' technique to determine the chromosomal content of spermatozoa from two bulls heterozygous for the 1/29 translocation and one normal bull (control). 5425 and 2702 sperm nuclei were scored, respectively, for the two heterozygous bulls, using whole chromosome painting probes of chromosomes 1 and 29. Very similar proportions of normal (or balanced) spermatozoa resulting from alternate segregation were observed (97.42% and 96.78%). For both heterozygous bulls, the proportions of nullisomic and disomic spermatozoa did not follow the theoretical 1:1 ratio. Indeed, proportions of nullisomic spermatozoa were higher than those of disomic sperma tozoa (1.40% vs 0.09% (bull 1) and 1.29% vs 0.15% (bull 2) for BTA1, and 0.65% vs 0.40% (bull 1) and 1.11% vs 0.63% (bull 2) for BTA29). The average frequencies of disomic and diploid spermatozoa in the normal bull were 0.11% and 0.05%, respectively.

Cleft palate associated with an unbalanced karyotype in piglets sired by a heterozygous carrier boar with a balanced constitutional reciprocal translocation.

The progeny of a commercial (Landrace x Duroc) x Large White boar contained a number of piglets with cleft palates. Chromosomal analyses of five affected piglets showed that they all had an identical unbalanced karyotype with partial monosomy of chromosome 16 and partial trisomy of chromosome 3, whereas the normal piglets in the litters had balanced karyotypes. The chromosomal imbalance was the direct result of a constitutional balanced reciprocal translocation carried by their heterozygote sire, described, according to the standard nomenclature, as t(3;16)(q23;q22).

A case of intersexuality in pigs associated with a de novo paracentric inversion 9 (p1.2; p2.2).

In several mammalian species, genetic defects can be responsible for the interruption of and/or the deviation from the sequential steps of normal gonadal differentiation, leading to a sex-reversal syndrome. In pigs, female-to-male sex-reversal conditions are particularly frequent, but their aetiologies remain unclear. Chromosomal abnormalities that co-occur with sex-reversal disorders can be useful in the identification of loci containing responsible or susceptibility genes. This report describes a female-to-male SRY-negative intersex pig with a de novo paracentric inversion of the short arm of one chromosome 9 (p1.2; p2.2). We have fine mapped the proximal chromosomal breakpoint of this rearrangement because it corresponded to a region potentially involved in the pig intersexuality. Fluorescent in situ hybridization (FISH) experiments carried out with Bacterial Artificial Chromosome (BAC) clones located within the critical region defined by genetic linkage analysis and ordered on the porcine RH map allowed us to locate the proximal breakpoint between markers SW2571 and SW539. Further investigations are currently in progress to find new markers inside this interval, in order to determine the BAC in which the break occurred.

Chromosomal abnormalities in hypoprolific boars.

Four new chromosomal rearrangements are reported in the domestic pig: 3 reciprocal translocations, rcp(4;12)(p13;q13) in a crossbred boar, rcp(1;7)(q17;q26) in a Large White purebred boar, rcp(1;6)(q17;q35) in a purebred synthetic paternal line boar, and a pericentric inversion inv(2)(p13q11) in a crossbred boar. The 1/7 reciprocal translocation and the pericentric inversion were detected in animals that had sired small litters. The effect of the 1/7 translocation was accurately determined: -4.5 piglets born per litter, i.e. -36%. Both the 1/6 and 1/7 reciprocal translocations were of maternal origin. All the chromosomal rearrangements were highlighted using GTG and/or RBG banding techniques. Chromosome painting experiments were also carried out to confirm the proposed hypotheses for the three reciprocal translocations.

A new reciprocal translocation in a subfertile bull.

Three bulls of the Montbéliarde breed that exhibited fertility rates lower than 30% following more than 400 artificial inseminations were examined. Semen quality (sperm motility and morphology) from these bulls was normal. Fertilizing ability estimated from in vitro embryo production results was studied for two of them. In vitro production rate was very low for one bull (A) and normal for the other (B). Cytogenetic analyses were carried out on the three bulls using chromosome banding techniques. These analyses revealed a reciprocal translocation (12;17)(q22;q14) in bull B. Based on family analyses, the hypothesis of a de novo origin of this rearrangement is proposed.

Chromosome banding studies in the Bateleur (Terathopius ecaudatus, Aves, Accipitridae).

The karyotype of the Bateleur (Terathopius ecaudatus) was studied with conventional and Ag-NOR staining, and using GTG and CBG banding. The karyotype organization is typically accipitrid, with satellites and few microchromosomes, close to the karyotypes of true vultures.

Five new cases of reciprocal translocation in the domestic pig.

Five new cases of reciprocal translocation in the domestic pig are described. Three of them, rep(3;5)(p1.3;q2.3), rep(6;13)(p1.5;q4.1) and rep(13;17)(q4.1;q1.1) were found in boars with decreased litter size. The remaining two were identified in animals karyotyped before reproduction: a young boar, rep(4;6)(q2.1;q2.8), and a gilt, rep(2;14)(q1.3;q2.7). A parental origin by inheritance of the translocations was established in cases 1, 4, and 5. A decrease in prolificacy of 43% and 34% was estimated in cases 1 and 3, respectively.

Nine new cases of reciprocal translocation in the domestic pig (Sus scrofa domestica L.).

Nine pigs with decreased litter size or sired by boars with decreased litter size were found to be reciprocal translocation carriers. Four Large White animals (two females and two males) demonstrated translocations involving chromosomes 1 and 9 (1p-;9p+), 11 and 13 (11q+;13q-), 3 and 13 (3;13)(p1.5;q3.1), and 15 and 17 (15;17)(q1.3;q2.1). Two Large White x Pietrain terminal boars demonstrated translocations involving chromosomes 11 and 16 (11;16)(p1.4;q1.4), and 6 and 14 (6;14)(q2.7;q2.1). The (9;15)(p2.4;q1.3) and (6;16)(q1.1;q1.1) translocations were found in a Large White x French Landrace boar, and in a commercial male line boar with decreased litter size, respectively. A Gascon breed boar with reduced prolificacy also had an abnormal karyotype, namely 38 XY, rcp(1;6)(q1.2;q2.2). Reduction in prolificacy was estimated accurately in cases 3, 5, 6, 7, and 9 (35%, 30%, 35%, 41%, and 56%, respectively). Rcp(1;6)(q1.2;q2.2) and rcp(6;16)(q1.1;q1.1) seemed to have been of de novo origin.

Characterization of reciprocal translocations in pigs using dual-colour chromosome painting and primed in situ DNA labelling.

We report the use of dual-colour chromosome painting to determine the exact nature of certain chromosome rearrangements observed in the pig (Sus scrofa domestica). The chromosomal abnormalities were detected by GTG- and RBG-banding techniques. The initially proposed interpretations were: (1) rcp(6;13)(p1.5;q4.1); (2) rcp(11;16)(p1.4;q1.4); (3) rcp(6;16)(p1.1;q1.1); (4) rcp(13;17)(q4.1;q1.1); (5) rcp(6;14)(q2.7;q2.1); (6) rcp(3;5)(p1.3;q2.3); (7) rcp(2; 14)(q1.3;q2.7); (8) rcp(15;17)(q1.3;q2.1). Hybridizations were carried out with biotin- and digoxigenin-labelled probes obtained by priming authorizing random mismatches polymerase chain reaction (PARM-PCR) amplification of porcine flow-sorted chromosomes. In some cases, i.e. (1), (4), (5), (6), (7) and (8), the fluorescence in situ hybridization (FISH) results allowed confirmation of the interpretations proposed with classical cytogenetic methods. Chromosome painting proved the reciprocity of the translocation in cases (1), (6) and (8), whereas modifications of the formula were proposed for case (2). Primed in situ DNA labelling (PRINS) experiments have also been carried out in case (3) using a primer specific for the centromeres of acrocentric chromosomes (first experiment) or a primer specific for the centromeres of a subset of meta- and submetacentric chromosomes including chromosome 6 (second experiment). It allowed us to demonstrate that the breakpoints occurred in the centromeric region of chromosome 16 and in the p. arm of chromosome 6, just above the centromere.

Molecular analysis of 60,XX pseudohermaphrodite polled goats for the presence of SRY and ZFY genes.

The polled mutation is characterized by a recessive, incompletely penetrant, hermaphroditic effect associated with the dominant genetic factor responsible for polledness in breeds of goat. The present study describes the external morphology, anatomy of the reproductive tract, histology, chromosomal constitution and Y chromosome screening of three intersex polled goats. The animals were tested for different Y-specific sequences, including SRY and ZFY. Using Southern blot and PCR amplification, no Y-derived sequences were detected in DNA from three 60,XX pseudohermaphrodite goats. This, therefore, excludes Y chromosome translocation and XX/XY chimaerism and mosaicism. This recessive mutation leading to sex reversal might be used to map and ultimately clone the autosomal genes implicated in the sex-determining pathway.

Does the 1/29 Robertsonian translocation affect the fertility of Blonde d'Aquitaine breed bulls?

The effects of the 1/29 translocation upon male fertility were studied by analysis of the results of 1,350,385 first artificial inseminations with the semen of Blonde d'Aquitaine or Coopelso-93 bulls (n=220). A binomial logit model was designed, taking into account the translocation of sire, breed of sire, breed of dam, year, AI center, and all interactions between translocation, and breed of sire, and breed of dam. Male fertility was not affected by the 1/29 translocation, and the nonreturn rates at 60 to 90 days of Blonde d'Aquitaine females inseminated with the semen of carrier bulls (135,632 first AI) or noncarrier bulls (585,949 first AI) were 74.88% and 74.75%, respectively.

A new case of Robertsonian translocation in cattle.

A new Robertsonian translocation was found in several animals of the Blonde d'Aquitaine breed. The fused chromosome analyzed by G- and R-banding results from the fusion of chromosomes 21 and 27. C-banding suggests that the fused chromosome is dicentric.

[Chromosomal structure or porcine lymphocytes effected by food additives]. / Structure chromosomique des lymphocytes du porc et additifs alimentaires.

Different concentrations of food additives were introduced in cultures of pig lymphocytes. No special chromosomal damage were induced by anticoccidians. On the contrary some antibiotics caused chromosomic anomalies. Chloramphenicol and furazolidone assayed in vitro and in vivo had also an antimitotic effect. The purpose of this work was to know the cytotoxic effect of some substances: a preliminary and cheap test could be a cytogenetic examination in vitro.