Free Access
Genet. Sel. Evol.
Volume 35, Number 4, July-August 2003
Page(s) 353 - 368
Genet. Sel. Evol. 35 (2003) 353-368
DOI: 10.1051/gse:2003028

Selection against genetic defects in conservation schemes while controlling inbreeding

Anna K. Sonessona, b, Luc L.G. Janssa and Theo H.E. Meuwissena

a  Institute of Animal Science and Health (ID-Lelystad), PO Box 65, 8200 AB Lelystad, The Netherlands
b  Current adress: AKVAFORSK (Institute of Aquaculture Research Ltd), PO Box 5010, 1432 Ås, Norway

(Received 9 April 2002; accepted 15 January 2003)

We studied different genetic models and evaluation systems to select against a genetic disease with additive, recessive or polygenic inheritance in genetic conservation schemes. When using optimum contribution selection with a restriction on the rate of inbreeding ( $\Delta$F) to select against a disease allele, selection directly on DNA-genotypes is, as expected, the most efficient strategy. Selection for BLUP or segregation analysis breeding value estimates both need 1-2 generations more to halve the frequency of the disease allele, while these methods do not require knowledge of the disease mutation at the DNA level. BLUP and segregation analysis methods were equally efficient when selecting against a disease with single gene or complex polygene inheritance, i.e. knowledge about the mode of inheritance of the disease was not needed for efficient selection against the disease. Smaller schemes or schemes with a more stringent restriction on $\Delta$F needed more generations to halve the frequency of the disease alleles or the fraction of diseased animals. Optimum contribution selection maintained $\Delta$F at its predefined level, even when selection of females was at random. It is argued that in the investigated small conservation schemes with selection against a genetic defect, control of $\Delta$F is very important.

Key words: genetic defects / selection / inbreeding / conservation

Correspondence and reprints: Anna K. Sonesson

© INRA, EDP Sciences 2003