Science - November 27, 2008

POLES SELECT GENES FOR RESISTANT CARP

Carp will be on the Christmas dinner menu in Poland again next month. Traditionally, this bony fish is mainly farmed in Eastern Europe. So it is no coincidence that two Polish PhD researchers who graduated this week in Wageningen wrote their theses about improving resistance to disease among carp.

Carp will be on the Christmas dinner menu in Poland again next month.
Polish carp, farmed in semi-intensive ponds, are prey to a range of viruses, bacteria and parasites. The Polish Institute of Ichthyobiology and Aquaculture in Golysz, with which the Wageningen immunologists are collaborating, is looking for genetic selection methods for obtaining resistant carp.

PhD student Krzysztog Rakus researched two sets of genes, DAB 1 and DAB 3, which control the fish’s immune system. He found that the DAB 1 group appeared to contain the most genetic variety, which is a condition for successful genetic selection. And he also found a clear relation between certain DAB 1 genotypes and the carp’s resistance to diseases, which makes DAB 1 an excellent marker for future breeding programmes for this fish breed.

Rakus’s compatriot Patrycia Jurecka looked for genetic variation in carp to raise their resistance to the blood parasite Trypanoplasma borrel. This parasite competes with the carp for iron. The transport protein transferrin, which provides the fish’s cells with iron, plays a key role in this. Jurecka found four different gene combinations for transferrin. Type D of this protein seemed the most vulnerable to the parasite, which led to a high concentration of parasites in the carp’s blood. Jurecka has not yet found the ultimate marker for optimal immunity to the blood parasite, but her research does lay the foundations for the Polish institute to build on in breeding resistant carp.

Co-supervisor Geert Wiegertjes of the Cell Biology and Immunology chair group is interested in more than sustainable carp farming. ‘For us the carp is a sort of guinea pig for studying fish immune systems. The knowledge gained will now be applied to the popular zebra fish, whose immune system is very like the carp’s.’ / Albert Sikkema

Krzysztop Rakus and Patrycia Jurecka were awarded their PhDs on 24 November by Huub Savelkoul, Professor of Cell Biology and Immunology

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