Cytogenetic screening of livestock populations in Europe: an overview

Abstract

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 ...).

A high incidence of leukocyte chimerism (60,XX/60,XY) in single born heifers culled due to underdevelopment of internal reproductive tracts

“…Unfortunately, knowledge on DSDs other than freemartinism in cattle is rather limited. Sex chromosome abnormalities responsible for DSD are not common in this species and X monosomy is almost absent, while cases of XXY, XYY, and XXX trisomies were reported rather rarely (Ducos et al 2008). There are very few reports on DSD females with a male karyotype (60,XY) and a lack of the SRY gene (Kawakura et al 1996;Payan-Carreira et al 2008).…”

Genetic health in Czech cattle population

“…Ducos et al (2008) published a survey of the cytogenetic screening of livestock populations in Europe. Developments in omics technologies may help overcome some limitations of traditional breeding programmes (Berry et al, 2011), but databases of phenotypes will be still necessary.The paper sums up the studies done in the Czech cattle population, and focuses on the various aspects of the genetic health.…”

A chromosome-wide QTL study on BTA29 affecting temperament traits in German Angus beef cattle and mapping of DRD4

“…The observed problems in parentage of this sire with DNA from blood could be clarified with DNA from semen. The most reported cytogenetic phenomena in cattle are XX/XY chimerism (Ducos et al, 2008;Peretti et al, 2008) and the Robertsonian translocation (Ducos et al, 2008;Iannuzzi et al, 2008;Vozdova et al, 2008). Therefore, blood chimersim can lead to mapping problems, especially in small populations, and therefore, exclusion and detection of chimera, at least in the sires of any research project, should be done, as it was already suggested for embryo transfer calves (Morris et al, 2009).…”