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The present review summarizes the basic cytogenetic information available pertaining to the most important Bovidae species, namely cattle, buffalo, sheep and goat, with the aim of tracing their evolutionary relationships and to provide – for the first time – the hypothetical ancestral karyotype of the Bovinae-Caprinae subfamilies, also in relation to the other nondomestic species which are included in this important taxonomic family. Evolution of the Bovinae-Caprinae autosomes and gonosomes is discussed on the basis of the most recent advances in chromosome banding, linkage studies, FISH-mapping and molecular information.

This paper describes the most common cytogenetic techniques we routinely adopt in our laboratories for producing high-resolution banding on prometaphase stage chromosomes, from synchronized or nonsynchronized blood cultures. Special emphasis is given to the FISH procedures applied to prometaphase chromosomes for mapping purposes. Each section includes historical information, basic principles for the given technique, its primary use in veterinary cytogenetics, and major limitations. Supplementary material (protocols and chemicals used) are available on our website. Even though these techniques mainly refer to the Bovidae, they can be easily extended and adapted to members of other taxa.

We analyzed chromosome aberrations (CAs), sister chromatid exchanges (SCEs), mitotic index (MI), and glucose 6‐phosphate dehydrogenase (G6PD) enzyme activity in human peripheral lymphocytes from three healthy donors exposed in vitro to different concentrations of gliphosate, vinclozolin, atrazine, and DPX‐E9636. The pesticides gliphosate, vinclozolin, and atrazine have been studied in a broad range of genetic tests with predominantly conflicting or negative results, whereas little is known about the genotoxicity of DPX‐E9636. In our experimental conditions, each chemical compound tested produced a dose‐related increase in the percent of aberrant cells and an increase of SCE/cell. Furthermore, at the highest concentrations of vinclozolin, atrazine, and DPX‐E9636, we observed a significant reduction of the mitotic index. The increase of G6PD activity in exposed lymphocyte cultures strongly indicated an induction of a pro‐oxidant state of the cells as an initial response to pesticide exposure. Environ. Mol. Mutagen. 32:39–46, 1998 © 1998 Wiley‐Liss, Inc.

Chromosomal homologies have been established between cattle (Bos taurus, 2n = 60) and eight species of spiral-horned antelope, Tribe Tragelaphini: Nyala (Tragelaphus angasii, 2n = 55male/56female), Lesser kudu (T. imberbis, 2n = 38male,female), Bongo (T. eurycerus, 2n = 33male/34female), Bushbuck (T. scriptus, 2n = 33male/34female), Greater kudu (T. strepsiceros, 2n = 31male/32female), Sitatunga (T. spekei, 2n = 30male,female) Derby eland (Taurotragus derbianus 2n = 31male/32female) and Common eland (T. oryx 2n = 31male/32female). Chromosomes involved in centric fusions in these species were identified using a complete set of cattle painting probes generated by laser microdissection. Our data support the monophyly of Tragelaphini and a clade comprising T. scriptus, T. spekei, T. euryceros and the eland species T. oryx and T. derbianus, findings that are largely in agreement with sequence-based molecular phylogenies. In contrast, our study suggests that the arid adaptiveness of T. oryx and T. derbianus is recent. Finally, we have identified the presence of the rob(1;29) fusion as an evolutionary marker in most of the tragelaphid species investigated. This rearrangement is associated with reproductive impairment in cattle and raises questions whether subtle distinctions in breakpoint location or differential rescue during meiosis underpin the different outcomes detected among these lineages.

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The effects of activation by 6-dimethylaminopurine (6-DMAP) and cycloheximide (CHX) on the development and chromosomal complement of sheep parthenogenetic and SCNT embryos were investigated. The results revealed that the blastocyst development of parthenogenetic embryos was significantly higher (P < 0.05) in 6-DMAP activated oocytes, compared to those activated with CHX (21.0 +/- 0.9 vs. 14.9 +/- 0.5, respectively). In contrast, the blastocyst frequencies did not significantly differ (P > 0.05) between the two activation treatment groups for SCNT embryos. The 6-DMAP or CHX treatment did not result in any significant difference in the blastocyst total cell number in either parthenote or SCNT embryos. The chromosomal analysis revealed that all the parthenogenetic embryos (100.0%) derived from 6-DMAP treatment, were chromosomally abnormal whereas in CHX-treated embryos, it was significantly lowered (93.6%, P < 0.05). Conversely, the proportions of chromosomally abnormal SCNT embryos did not significantly differ (P > 0.05) among the 6-DMAP and CHX- treated embryo groups (60.0% vs. 56.2%, respectively). This study demonstrated that oocyte activation agents such as DMAP and CHX have differing effects on meiotic or mitotic nuclei. The study also highlighted the feasibility of using bovine X and Y chromosome specific painting probes in sheep embryos.