Cytogenetic ‘FISH-ing’: The search for chromosomal aberrations in domestic animals

Rationale It is important for you to be able to review existing literature, from a wide range of sources, analyse this material in a specific context and draw conclusions from this. Task Fluorescence in situ hybridisation (FISH) is a widely used cytogenetic technique. The process involves the use of fluorescent probes; these are essentially fluorescently labelled short stretches of single stranded DNA with a high level of sequence complementarity to specific sections of a chromosome. Chromosomal DNA is traditionally denatured by heating and the probe DNA is then able to selectively hybridise to its complement (if it is present), followed by visualisation under a fluorescence microscope. FISH is an extremely versatile technique that was first used on in vitro fertilisation human embryos in preimplantation genetic diagnosis (PGD) cases in the early 1990s (Delhanty et al. 1993). The technique is effective in the diagnosis of diseases such as Down’s syndrome as well as some cancers (such as leukaemia), and it is widely used a comparative technique in evolutionary studies. This essay should focus on the application of ‘FISH-ing’ for chromosomal aberrations in domesticated animals (for example, livestock, horses, companion animals and avian species). Most of your information should be from peer reviewed scientific journals, with minimal use of textbooks. Figures, figure legends and references are excluded from words counts.