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Hybridization of chromosome 3 (green) and 16 (red) BAC probes on decondensed sperm nuclei of the rob(3;16) heterozygous carrier bull. a Normal sperm nucleus: 3q/16q (alternate segregation). b Disomic sperm nucleus for chromosome 3: 3q/der(3q;16q) (adjacent segregation). c Nullisomic sperm nucleus for chromosome 3: 16q (adjacent segregation). d Disomic sperm nucleus for chromosome 16: 16q/der(3q;16q) (adjacent segregation). e Nullisomic sperm nucleus for chromosome 16: 3q (adjacent segregation). f Sperm nucleus resulting from the 3:0 segregation or diploid sperm nucleus: 3q/16q/der(3q;16q) or 3q/3q/16q/ 16q. Scale bar, 10 µm.
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Robertsonian translocations are the most frequent chromosomal rearrangements detected in cattle. Here, we report on the detection of a new Robertsonian translocation between chromosomes BTA3 and BTA16. This rob(3;16) was dicentric, suggesting that its occurrence was recent. FISH analysis of decondensed sperm nuclei revealed a relatively low rate of...
Citations
... Finally, the rob(18;21) carrier was within the normal range for both male fertility and juvenile mortality. Therefore, we assume that this bull produced only a low proportion of chromosomally unbalanced spermatozoa resulting from adjacent meiotic segregation, that is, possibly ∼≤5%, as previously reported, for example, for carriers of rob(1;29), rob(1;21), rob(7;21), and rob(3;16) (Tateno et al. 1994;Bonnet-Garnier et al. 2006;Barasc et al. 2019). ...
In this paper, we developed a highly sensitive approach to detect inter-chromosomal rearrangements in cattle by searching for abnormal linkage disequilibrium patterns between markers located on different chromosomes in large paternal half-sib families genotyped as part of routine genomic evaluations. We screened 5571 families of artificial insemination sires from 15 breeds and revealed 13 putative inter-chromosomal rearrangements, 12 of which were validated by cytogenetic analysis and long-read sequencing. These consisted of one Robertsonian fusion, 10 reciprocal translocations, and the first case of insertional translocation reported in cattle. Taking advantage of the wealth of data available in cattle, we performed a series of complementary analyses to define the exact nature of these rearrangements, investigate their origins, and search for factors that may have favored their occurrence. We also evaluated the risks to the livestock industry and showed significant negative effects on several traits in the sires and in their balanced or aneuploid progeny compared with wild-type controls. Thus, we present the most comprehensive and thorough screen for inter-chromosomal rearrangements compatible with normal spermatogenesis in livestock species. This approach is readily applicable to any population that benefits from large genotype data sets, and will have direct applications in animal breeding. Finally, it also offers interesting prospects for basic research by allowing the detection of smaller and rarer types of chromosomal rearrangements than GTG banding, which are interesting models for studying gene regulation and the organization of genome structure.
... He demonstrated that not only do chromosome abnormalities occur in domestic livestock, but they also have physiological effects on carrier animals with economic consequences [37] associated particularly with reproductive problems. Fertility reduction in carrier heterozygous bulls is caused by the production of unbalanced gametes (approximately 3.22% unbalanced sperms in a carrier bulls [38]) during meiosis (nullisomy or disomy for the chromosomes involved in the translocation) ( Figure 2). ...
... Rob(1;21), rob(23;26), rob (24;26), and rob(26;29) were reported by Arslan et al. [41] in Holstein cattle-cows with Repeat Breeder Syndrome usually connected with the infertility problem (Table 1). A finding of a new dicentric Robertsonian translocation rob(3;16) in a bull from the Montbéliarde dairy cattle breed with a significant interchromosomal effect (ICE) for two different autosomes, BTA17 and BTA20, was recently published [38]. The ICE could be probably caused by the general disorganization of the meiotic spindle during metaphases I and II. ...
Chromosomal aberrations and their mechanisms have been studied for many years in livestock. In cattle, chromosomal abnormalities are often associated with serious reproduction-related problems, such as infertility of carriers and early mortality of embryos. In the present work, we review the mechanisms and consequences of the most important bovine chromosomal aberrations: Robertsonian translocations and reciprocal translocations. We also discuss the application of bovine cell cultures in genotoxicity studies.
... Regarding the centromeric fusion, the proportion of meiotic products from adjacent segregation modes in M. gouazoubira is consistent with that reported in the literature for RT in domestic species such as bulls e 2.58%e5.42% [26,51], boars e 3.16% [25] and mice e 8.00%e11.50% [52]. ...
... The ICE is defined as a disturbance in meiosis, where rearranged chromosomes disrupt disjunction and distribution of other chromosome pairs not involved in the rearrangement, including also both sexual chromosomes, X and Y [20,53,54]. This was previously observed in human RT carriers with a high frequency of aneuploid sperm, and, recently, also in cattle, in heterozygous rob(3;16) carrier [20,51,54,55]. Although there is still controversy about whether this phenomenon would represent a factual reproductive genetic risk for carriers [20,51,53e56]. ...
The genus Mazama stands out among the Neotropical deer due to their wide intra and interspecific karyotypic diversification, which is associated with an accentuated chromosomal fragility. There are reports of heterozygous Robertsonian translocation (RT) carriers in a free-range population of Mazama gouazoubira (brown brocket deer), as well as in captive animals of this and other species of the genus. To analyze possible negative impacts of heterozygous chromosome rearrangements on reproductive fitness of the carriers, we performed an analysis of sperm meiotic segregation in four brown brocket bucks, carriers of a rob(4;16), and compared the results with those of a normal buck. We established a reliable FISH and sperm-FISH protocol for the brown brocket deer using bovine (Bos taurus; diploid number, 2n = 60) whole chromosome painting (WCP) and BAC probes. Using BAC probes, we revealed the presence of a paracentric inversion (PAI) of the fused chromosome 4 in two of the four analyzed RT carriers. The mean frequency of normal/balanced sperm in the translocation carriers was significantly lower than in the normal buck (94.78% vs 98.4%). The mean value of total unbalanced spermatozoa was almost doubled in the RT/PAI carriers (6.68%) when compared to RT carriers (3.76%), but the difference was not statistically significant. This study demonstrated the efficiency of FISH with bovine WCP and BAC probes in the characterization of chromosome rearrangements and gametic segregation patterns in brown brocket deer. Our results indicate a low to moderate increase in the rates of unbalanced meiotic segregation products in brown brocket bucks heterozygous for RT and RT/PAIs.
... 3.16%, and 8-11.5%, respectively) [64][65][66][67]. These findings may suggest a low negative effect on the reproductive fitness of heterozygous carriers of RT reported here for MAM, unlike that reported for several RT in humans where there is a wide variation in reproductive impact (0.2-49.1% of adjacent segregation products) [68]. ...
Chromosomal polymorphism plays a major role in speciation processes in mammals with high rates of karyotypic evolution, as observed in the family Cervidae. One remarkable example is the genus Mazama that comprises wide inter- and intra-specific chromosomal variability. To evaluate the impact of chromosomal polymorphisms as reproductive barriers within the genus Mazama, inter-specific hybrids between Mazama gouazoubira and Mazama nemorivaga (MGO × MNE) and intra-specific hybrids between cytotypes of Mazama americana (MAM) differing by a tandem (TF) or centric fusion (Robertsonian translocations—RT) were evaluated. MGO × MNE hybrid fertility was evaluated by the seminal quality and testicular histology. MAM hybrids estimation of the meiotic segregation products was performed by sperm-FISH analysis. MGO × MNE hybrids analyses showed different degrees of fertility reduction, from severe subfertility to complete sterility. Regarding MAM, RT, and TF carriers showed a mean value for alternate segregation rate of 97.74%, and 67.23%, and adjacent segregation rate of 1.80%, and 29.07%, respectively. Our results suggested an efficient post-zygotic barrier represented by severe fertility reduction for MGO × MNE and MAM with heterozygous TF. Nevertheless, RT did not show a severe effect on the reproductive fitness in MAM. Our data support the validity of MGO and MNE as different species and reveals cryptic species within MAM.
... While the original use of the term interchromosomal effect described the change in genome-wide exchange frequency in the presence of an inversion, more recent work in humans and other mammals has used the term to mean something entirely different: the nondisjunction of a normal pair of homologous chromosomes in the presence of a translocation involving other chromosomes (cf. Estop et al. 2000;Eichenlaub-Ritter 2005;Barasc et al. 2019). A PubMed search for "interchromosomal effect" in mid-2020 yielded 150 results. ...
The term interchromosomal effect was originally used to describe a change in the distribution of exchange in the presence of an inversion. First characterized in the 1920s by early Drosophila researchers, it has been observed in multiple organisms. Nearly half a century later, the term began to appear in the human genetics literature to describe the hypothesis that parental chromosome differences, such as translocations or inversions, may increase the frequency of meiotic chromosome nondisjunction. Although it remains unclear if chromosome aberrations truly affect the segregation of structurally normal chromosomes in humans, the use of the term interchromosomal effect in this context persists. This article explores the history of the use of the term interchromosomal effect and discusses how chromosomes with structural aberrations are segregated during meiosis.
The discovery of the Robertsonian translocation (rob) involving cattle chromosomes 1 and 29 and the demonstration of its deleterious effects on fertility focused the interest of many scientific groups on using chromosome banding techniques to reveal chromosome abnormalities and verify their effects on fertility in domestic animals. At the same time, comparative banding studies among various species of domestic or wild animals were found useful for delineating chromosome evolution among species. The advent of molecular cytogenetics, particularly the use of fluorescence in situ hybridization (FISH), has allowed a deeper investigation of the chromosomes of domestic animals through: (a) the physical mapping of specific DNA sequences on chromosome regions; (b) the use of specific chromosome markers for the identification of the chromosomes or chromosome regions involved in chromosome abnormalities, especially when poor banding patterns are produced; (c) better anchoring of radiation hybrid and genetic maps to specific chromosome regions; (d) better comparisons of related and unrelated species by comparative FISH mapping and/or Zoo-FISH techniques; (e) the study of meiotic segregation, especially by sperm-FISH, in some chromosome abnormalities; (f) better demonstration of conserved or lost DNA sequences in chromosome abnormalities; (g) the use of informatic and genomic reconstructions, in addition to CGH arrays, to predict conserved or lost chromosome regions in related species; and (h) the study of some chromosome abnormalities and genomic stability using PCR applications. This review summarizes the most important applications of molecular cytogenetics in domestic bovids, with an emphasis on FISH mapping applications.
After discovering the Robertsonian translocation rob(1;29) in Swedish red cattle and demonstrating its harmful effect on fertility, the cytogenetics applied to domestic animals have been widely expanded in many laboratories in order to find relationships between chromosome abnormalities and their phenotypic effects on animal production. Numerical abnormalities involving autosomes have been rarely reported, as they present abnormal animal phenotypes quickly eliminated by breeders. In contrast, numerical sex chromosome abnormalities and structural chromosome anomalies have been more frequently detected in domestic bovids because they are often not phenotypically visible to breeders. For this reason, these chromosome abnormalities, without a cytogenetic control, escape selection, with subsequent harmful effects on fertility, especially in female carriers. Chromosome abnormalities can also be easily spread through the offspring, especially when using artificial insemination. The advent of chromosome banding and FISH-mapping techniques with specific molecular markers (or chromosome-painting probes) has led to the development of powerful tools for cytogeneticists in their daily work. With these tools, they can identify the chromosomes involved in abnormalities, even when the banding pattern resolution is low (as has been the case in many published papers, especially in the past). Indeed, clinical cytogenetics remains an essential step in the genetic improvement of livestock.
