Meiotic segregation analysis in cows carrying the t(1;29) Robertsonian translocation

Cytogenetics was conceived in the late 1800s and nurtured through the early 1900s by discoveries pointing to the chromosomal basis of inheritance. The relevance of chromosomes to human health and disease was realized more than half a century later when improvements in techniques facilitated unequivocal chromosome delineation. Veterinary cytogenetics has benefited from the information generated in human cytogenetics which, in turn, owes its theoretical and technical advancement to data gathered from plants, insects and laboratory mammals. The scope of this science has moved from the structure and number of chromosomes to molecular cytogenetics for use in research or for diagnostic and prognostic purposes including comparative genomic hybridization arrays, single nucleotide polymorphism array-based karyotyping and automated systems for counting the results of standard FISH preparations. Even though the counterparts to a variety of human diseases and disorders are seen in domestic animals, clinical applications of veterinary cytogenetics will be less well exploited mainly because of the cost-driven nature of demand on diagnosis and treatment which often out-weigh emotional and sentimental attachments. An area where the potential of veterinary cytogenetics will be fully exploited is reproduction since an inherited aberration that impacts on reproductive efficiency can compromise the success achieved over the years in animal breeding. It is gratifying to note that such aberrations can now be tracked and tackled using sophisticated cytogenetic tools already commercially available for RNA expression analysis, chromatin immunoprecipitation, or comparative genomic hybridization using custom-made microarray platforms that allow the construction of microarrays that match veterinary cytogenetic needs, be it for research or for clinical applications. Judging from the technical refinements already accomplished in veterinary cytogenetics since the 1960s, it is clear that the importance of the achievements to date are bound to be matched or out-weighed by what awaits to be accomplished in the not-too-far future.

Section: Fluorescence In Situ Hybridizationsupporting

confidence: 75%

Veterinary cytogenetics: past and perspective

Basrur

Stranzinger²

2008

“…Some questions, very difficult to investigate in humans for technical and ethical reasons, as for instance the difference of segregation profiles between males and females, or the variability of segregation profiles between individuals having the same karyotype, or between sperm samples for the same individual, could be thoroughly documented (e.g. Pinton et al, 2005;Bonnet-Garnier et al, 2007). In Canada, the limited access to relevant foetal oocytes which precluded direct study of meiotic events in female carriers was overcome by the use of somatic cell nuclear transfer in cattle to study meiosis in a female carrying a sex-dependent fertilityimpairing X-chromosome abnormality (Rho et al, 2007).…”

Section: Discussionmentioning

confidence: 99%

Cytogenetic screening of livestock populations in Europe: an overview

Ducos

Révay

Kovács

et al. 2008

Self Cite

118

160

Clinical animal cytogenetics development began in the 1960’s, almost at the same time as human cytogenetics. However, the development of the two disciplines has been very different during the last four decades. Clinical animal cytogenetics reached its ‘Golden Age’ at the end of the 1980’s. The majority of the laboratories, as well as the main screening programs in farm animal species, presented in this review, were implemented during that period, under the guidance of some historical leaders, the first of whom was Ingemar Gustavsson. Over the past 40 years, hundreds of scientific publications reporting original chromosomal abnormalities generally associated with clinical disorders (mainly fertility impairment) have been published. Since the 1980’s, the number of scientists involved in clinical animal cytogenetics has drastically decreased for different reasons and the activities in that field are now concentrated in only a few laboratories (10 to 15, mainly in Europe), some of which have become highly specialized. Currently between 8,000 and 10,000 chromosomal analyses are carried out each year worldwide, mainly in cattle, pigs, and horses. About half of these analyses are performed in one French laboratory. Accurate estimates of the prevalence of chromosomal abnormalities in some populations are now available. For instance, one phenotypically normal pig in 200 controlled in France carries a structural chromosomal rearrangement. The frequency of the widespread 1;29 Robertsonian translocation in cattle has greatly decreased in most countries, but remains rather high in certain breeds (up to 20–25% in large beef cattle populations, even higher in some local breeds). The continuation, and in some instances the development of the chromosomal screening programs in farm animal populations allowed the implementation of new and original scientific projects, aimed at exploring some basic questions in the fields of chromosome and/or cell biology, thanks to easier access to interesting biological materials (germ cells, gametes, embryos ...).

“…Analysis of oocytes produced by sow carriers of the rcp(3; 15)(q27;q13) and the rcp(12; 14)(q13;q21) and comparison with the male meiotic products revealed significant differences between sexes (Pinton et al, 2005) demonstrating the difference of the male and female meiotic process. In the bovine species the study of 394 oocytes of 1/29 Robertsonian translocation female carriers revealed 21.83% of diploid oocytes and 5.19% of chromosomally unbalanced sets excluding diploidies (Bonnet-Garnier et al, 2008).…”

Section: Analysis Of the Meiotic Productsmentioning

confidence: 99%

Chromosomal abnormalities, meiotic behavior and fertility in domestic animals

Villagómez

Pinton²

2008

Self Cite

Since the advent of the surface microspreading technique for synaptonemal complex analysis, increasing interest in describing the synapsis patterns of chromosome abnormalities associated with fertility of domestic animals has been noticed during the past three decades. In spite of the number of scientific reports describing the occurrence of structural chromosome abnormalities, their meiotic behavior and gametic products, little is known in domestic animal species about the functional effects of such chromosome aberrations in the germ cell line of carriers. However, some interesting facts gained from recent and previous studies on the meiotic behavior of chromosome abnormalities of domestic animals permit us to discuss, in the frame of recent knowledge emerging from mouse and human investigations, the possible mechanism implicated in the well known association between meiotic disruption and chromosome pairing failure. New cytogenetic techniques, based on molecular and immunofluorescent analyses, are allowing a better description of meiotic processes, including gamete production. The present communication reviews the knowledge of the meiotic consequences of chromosome abnormalities in domestic animals.