Maintenance of a collection of isogenic strains

Scientific leaders: E. Quillet, F. Krieg, R. Guyomard, N. Dechamp (GABI - GenAqua)
Technical leaders: L. Goardon, F. Guyvarc’h, L.-A. Le Ven,
Contact : Edwige Quillet

Start date: 2000      Planned duration: > 15 years

INRA research unit partners

• GABI-GenAqua unit: creation and monitoring of strains
• Physiologists and nutritionists of the PHASE department (LPGP, NuMeA)
• Pathologists of the Animal Health department (VIM).

Access conditions: available in the framework of scientific collaboration with the INRA research unit GABI and, on a case-by-case basis, under certain conditions (material transfer agreement (MTA) regarding the use of animals and derived tissues or cells).

Objectives

The great plasticity of reproduction in fish allows the production of original genetic groups. In particular, gynogenesis (reproduction from maternal genetic material alone) allows the production in two generations of homozygous isogenic strains, which have many advantages in experimental approaches. The absence of genetic variability within the group facilitates analysis of certain characteristics difficult to measure at the individual level. It also simplifies genetic and genomic analyses. Once established, each strain can be maintained identically over generations, which permits direct comparison of observations made at different times.

Hybrid isogenic strains were also produced by crossing two closely related species, Oncorhynchusmykissand O. clarki. This hybridisation revealed a completely original reproductive system: production of diploid eggs with a genotype identical to that of the mother.

Experimental design

More than 20 strains (18 homozygous strains and 7 hybrid strains) are maintained at PEIMA. To ensure a regular supply of experimental batches, it is necessary to have breeders at each egg-laying season in most strains. Several cohorts of different ages (1 to 3 years) are thus present at the facility.

Because of their great phenotypic variability, including that in reproductive characteristics, each strain requires individual management. As a function of research objectives, the strains are used in pure form or crossed. Experiments can occur on site, or derived batches can be transported at the eyed-egg stage to other experimental units.