The facilities of the Experimental Units provide the phenotypes necessary for the study of genetic determinism of traits and gene regulation. Since many collaborations are implicated, they are important assets to European research. The facilities provide genotype models, specific, large sized multiple generation genetic systems as well as the equipment and know-how that are necessary to produce the desired phenotypes. Studies led often with many partners are both fundamental and targeted. They concern agronomic traits but also biomedical models. They often have an impact on the industry at different levels from the identification of criteria and tool selection to the transfer of original genotypes.
On the contrary to traditional experiments that intend to decrease individual variability (considered to be residual) by using animals that are standardised as much as possible, genetic experiments use this individual information to try to identify what information is of genetic origin from that which is not, or what information is due to a particular gene or combination of genes.
These experiments often involve a large number of animals and several generations. They require all steps of breeding, in particular reproduction.
These important programmes that last several years are conceived, performed, analysed and valorised in collaboration with experts of the functions studied (physiologists, pathologists or technologists). They often have several objectives. Even though quantitative geneticists are often in charge of the technical aspects, these experiments are often pluridisciplinary and involve different research teams.
The main experimental programmes performed in our units are the following :
Selection experiments aimed at producing terminal strains, by selecting a population for a particular trait over several generations. The strains may be closed or open, therefore externalising the selection effort in commercial populations. These experiments allow the identification of the genetic determinism of a trait, the estimation of its relation with other traits, including the physiological components, and provide animal models for partnerships with other fields of study.
Genotype comparisons are easier to perform (breed or line comparisons). For the study of genes or gene combinations, the scientist tries to build genotypes with a constant genetic basis.
QTL detection programmes are led by crossbreeding or with intra breed crosses over several generations. In crossbreeding, either divergent selected lines or populations that are very different for a trait are studied. Since breeding populations are rarely from the same paternal family, the experiments include many individuals (500 to 1000) and involve a specific family structure. Either a particular trait is studied or many, therefore involving the evaluation of many phenotypes.
Fine mapping experiments of genes logically follow QTL detection programmes. By crossbreeding more advanced generations, researchers intend to produce descendants of selected parents in order to gather combinations in the chromosomal regions studied.
Genotype-environment interactions involve experiments that use several genotypes in different environments. This variability of the environment can be obtained using several breeding sites or different types of breeding management or the environment can be controlled.
Occasionally, other studies are performed in addition to research programmes in order to treat a specific question.
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